# Why the love for high distortion drivers?



## jimbno1 (Apr 14, 2008)

I was wondering why the big love for high distortion drivers such as Dynaudio, HAT, and Morel mids, Ribbon tweeters, Maggies, etc. At least based off Zaph's testing of some of these speakers. I know everyone says let your ears decide, but why do our ears (some anyway) prefer distorted speakers? 

It has been some time since I have heard 3-way Dynaudio setup but to tell the truth the last time I did I was completely underwhelmed. The car was professionally tuned by a well respected shop. I can say the same for a buddy of mine's 3-way Morel setup (not professionally tuned). I actually preferred his previous Boston speakers. 

All that being said I wished I had never sold my set of Morel 3-ways with the dome mid. I thought they sounded very good in testing them, especially with the mid off-axis.

I am as guilty as anyone in this regard since I have planar dynamic home speakers. They are more akin to BG speakers than true ribbons though, and I am not sure how much distortion they actually have, but i would suspect it is much higher than a convential dome tweeter. 

I don't want to start a flame war with the Morel and Dynaudio enthusiasts. Although I do want to hear what makes these speakers special in their opinion. I am searching for a logical explanation.


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## BigRed (Aug 12, 2007)

I don't recall zaph testing the hybrid drivers.....can you point me to that review please?


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## TREETOP (Feb 11, 2009)

High distortion drivers go well with vinyl recordings and tube amplifiers, right? :inout:


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## PureDynamics (Nov 3, 2007)

Where are these tests you talk about?


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## methodsound (Oct 1, 2009)

What speakers are you recommending as an alternative?


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## Dryseals (Sep 7, 2008)

jimbno1 said:


> I was wondering why the big love for high distortion drivers such as Dynaudio, HAT, and Morel mids, Ribbon tweeters, Maggies, etc. At least based off Zaph's testing of some of these speakers. I know everyone says let your ears decide, but why do our ears (some anyway) prefer distorted speakers?
> 
> It has been some time since I have heard 3-way Dynaudio setup but to tell the truth the last time I did I was completely underwhelmed. The car was professionally tuned by a well respected shop. I can say the same for a buddy of mine's 3-way Morel setup (not professionally tuned). I actually preferred his previous Boston speakers.
> 
> ...


It's quite simple, cool name, high price, must be good, has to be better than some el cheapo speakers.

Hearing is a learned thing. If you play a musical instrument, you'll know what I'm talking about. Ever since I've been in this game, if you pay more for it, it has to sound better, if it looks cooler, it has to sound better.

Some one a few days back asked what should they look for in a speaker, simple question and a complete lack of response. Why, because no one knows???

I find it funny that some one will draw down on the specs for an amp, but drop twice the money on speakers without any real world spec on them. All the T/S parameters tell you is low level response. The most importamt part of your system and you can't even get a distortion chart on them???

The manufacturers have the data for all kinds of things, but if they published it, they would loose sales.

I have tested some of the "golden girls" of speakers and for the most part they do not perform any where near their cost. But that plays right into the same thing as the manufacturers of home speakers. They drop $150 worth of raw drivers into them, give them a pretty box and charge you mega bucks for them. But they sure do look pretty and they have a name that sounds like they should be the best.


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## rommelrommel (Apr 11, 2007)

Psychoacoustics?

Last setup I ran was Elate 3 ways although...


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## Gilbert (Oct 21, 2009)

Why not ask the manufacturer?? To explain the phenomenon? I really think it has to do with "EGO", bragging rights, you name it they (the manufacturers) know. They definitely have the buyer psychological profile down pat.
Most of us don't have a trained ear.. So my 2 cents is because they sound good to me and that is what really matters, not numbers, not specs... but how well do they sound to you. It would be a great test, to offer a top line speaker, in a Jensen box and let people test them and see what they think. Then give them the same speaker in the Morel or DynAudio box and lets hear what they have to say..
I bet you some will swear by that topline brand and bad mouth the supposedly Jensen speaker. Its in their heads.......


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## thehatedguy (May 4, 2007)

Cars are not houses. We have much more problems with our listening environment than a house.

I wouldn't get too caught up in reading these tests. You may have the ultra wizz engineered speaker...on paper. But it might sound like poop.


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## jimbno1 (Apr 14, 2008)

To Big Red's point Zaph did not test the HAT drivers. npdang did a test of the Legatia 3 versus the Trius. 
http://www.diymobileaudio.com/forum/member-product-reviews/2974-legatia-3-vs-trius-3-a.html

npdang quote below:

It's very easy to see that the Trius has significantly lower non-linear distortion than the Legatia. Second and third order distortion were generally at least -15db lower, and fourth order and higher products much lower as well. The tests were taken at about 96dbspl @1m. A fairly difficult level for such small drivers to produce full range.

Response from Scott Buwalda
Rob:

I couldn't agree more. We have had great success using our Legatia's into the 140 Hz region. And despite the distortion on paper, the focussed imaging and staging provided from one set of drivers far outweighs potential pitfalls. All of the fundamental vocal cues through one pair of drivers really can't be beat...

Scott


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## Dryseals (Sep 7, 2008)

thehatedguy said:


> Cars are not houses. We have much more problems with our listening environment than a house.
> 
> I wouldn't get too caught up in reading these tests. You may have the ultra wizz engineered speaker...on paper. But it might sound like poop.


I disagree, distortion is distortion. Our sound field can be made better, but it takes work, time and analyzing the whys.

To say our listening enviroment can't be made to be that of a home is to admit defeat before we start.

All the testing does is give us a better start and handle on what we enjoy. I would never purchase equipment based on what some one would say is good enough.


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## thehatedguy (May 4, 2007)

Distortion isn't distortion. Not all of it is audible or matters to how we perceive sound.

And to say that our listening environment can't be made like a home isn't defeatist...it is being a realist.


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## armen818 (Sep 18, 2009)

this is going to be a stupid Q, but who makes Trius 3 speakers??

is it this??
TG9FD-10-04 TG/TC 3½″ Full Range Vifa Datasheet



BTW: i really like npdang's reviews and comparisons of speakers


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## chipss (Nov 13, 2009)

Dryseals, thanks for the post.

I have prided myself as understanding how a speaker works and reading specs…that said, I know I am still learning…

I admit, I do not know anything about distortion charts, how to interpret the chart or data, or anything about them.



I understand to a lesser degree about speaker distortion in guitar amp speakers, the huge differences in speakers there, same amp and cab completely different tone with a speaker change, such as an old vintage Jensen distorts a great deal, cone break up…and all… is great for blues tones, a vintage jbl can be way clean and great for country tones, or cleaner tones…

I would think my car stereo should be as clean as I can get it….and then from there deal with Psychoacoustics.

I sure would like to know more about speaker distortion and chart reading.


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## methodsound (Oct 1, 2009)

Legatia 3 versus the Trius.
[url said:


> http://www.diymobileaudio.com/forum/member-product-reviews/2974-legatia-3-vs-trius-3-a.html[/url]
> 
> npdang quote below:
> 
> It's very easy to see that the Trius has significantly lower non-linear distortion than the Legatia. Second and third order distortion were generally at least -15db lower, and fourth order and higher products much lower as well. The tests were taken at about 96dbspl @1m. A fairly difficult level for such small drivers to produce full range.


Since both drivers were tested at 96db / full range, I would ask if cone area would be a factor? The Sd of the Trius is 36.32cm^2 and the Legatia L3 is 27.33cm^2. The smaller cone would have to play with higher excursion then the larger one in order to reach the 96db mark right?


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## ChrisB (Jul 3, 2008)

Dryseals said:


> To say our listening enviroment can't be made to be that of a home is to admit defeat before we start.


Several audiophiles, as well as myself, will disagree with this statement. In the home, one can build a solid, super dead to the world room, and set up the most expensive equipment known to man.

In a car that will never happen. First, you have glass, next you have plastic/fiberglass/wood etc. panels that are all going to cause reflections and resonate at weird frequencies. Of course, driving a vehicle 70 MPH down the interstate OR during a torrential downpour will adversely impact the vehicle's listening environment with extraneous noise. So will other vehicles passing you by. What is the average noise floor to overcome in a vehicle again? What about cabin gain?

Sorry, no one can convince me that a car can be made as good as a home for a listening environment. I won't even get into the theories required for accurate stereophonic reproduction, but I will say that most recordings WERE NOT engineered to be reproduced in a vehicle.


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## methodsound (Oct 1, 2009)

06BLMUSTANGGT said:


> Several audiophiles, as well as myself, will disagree with this statement. In the home, one can build a solid, super dead to the world room, and set up the most expensive equipment known to man.
> 
> In a car that will never happen. First, you have glass, next you have plastic/fiberglass/wood etc. panels that are all going to cause reflections and resonate at weird frequencies. Of course, driving a vehicle 70 MPH down the interstate OR during a torrential downpour will adversely impact the vehicle's listening environment with extraneous noise. So will other vehicles passing you by. What is the average noise floor to overcome in a vehicle again? What about cabin gain?
> 
> Sorry, no one can convince me that a car can be made as good as a home for a listening environment. I won't even get into the theories required for accurate stereophonic reproduction, but I will say that most recordings WERE NOT engineered to be reproduced in a vehicle.


+1:thumbsup:

But I will point out that a car has one advantage: Your listening position in the room is fixed.


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## emperorjj1 (Sep 10, 2008)

TREETOP said:


> High distortion drivers go well with vinyl recordings and tube amplifiers, right? :inout:


LOL :bowdown::bowdown::bowdown::bowdown:


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## The J (Oct 27, 2009)

I've heard the term "clinical" used to describe some speakers (well, headphones actually). As far as I could tell the term means that the speaker was "too accurate", removing the fun or joy of listening to anything on them. So then does such a derogatory term imply that there is distortion that we find enjoyable or that music can be distorted in a good way?

Maybe high-end speakers have simply managed to distort our audio in a good way...? :shrug:


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## diegoejea (May 11, 2009)

I am an owner of dynaudio mw162, audio & telecomunincations engineer, and sound enthusiast for the last 15 years.

I don´t want to defend any driver I don´t like. I only look for the highest sound quality for my car, and I always try to critizice the equipment I buy, regardless its cost. I have thrown away DLS Nobelium, and other supposed Hi End systems.

My dynaudio driver, is the best sounding, cristal clear midbass driver I have ever had. For sure, it has flaws. One of them is its capability to play midrange sound (500 Hz and upper). He plays it loud (like subwoofers do with 100-200 Hz freqs), but he has not enough acceleration capabilities to play them as cristal clear sounding, real, sharp, as a smaller driver would do. But it happens to all woofers. Some of them are sharp higher, others are lower. but all of them are not as good for midrange as the real sound has to be. 

For bass and midbass, these mw162 are incredible, amazing. The sound is extremely controlled, clean and quiet. You can ear the silence between transients. For sure there are better midwoofers. But, let´s don´t say these drivers are liked by us because the high distortion results obtained by somebody. 


What I can say is, why are you giving so much importance to these distorsion results? 

Even supposed those distorsion measures are taken in perfect conditions and following a right procedure (I can´t say anything about the proc because I haven´t read how these people do it. Al leats one sign of it is well done, would be everybody who does the test, get the same figures and results... but I am afraid sometimes not...), even supposed these distortion measures are accepted, why are they the only thing to evaluate the sound quality of the speaker? Is this a new fashion?

On the one hand, to get a good sounding speaker, a *faithful* transductor (Fidelity), there are much more things to take in consideration, to measure (not showed in the specifications sheets the manufacturers give to us), but needed to design, to create a loudspeaker.

On the other hand, is not possible to evaluate distorsion results just by the plot or figures. Is needed to apply Psychoacoustics to know which distortion has more final effect to the ear. For sure a speaker with 0 distortion is a perfect speaker (regarding distortion, what doesn´t mean it is perfect at other "skills" a speaker must have), but a speaker with "4" distortion is not better than other with "7" (just to say invented simple quantities), we have to evauate it psychoacoustically. You can get a speaker with very low distortion, but the characteristics of the remaining distortion can be more harmful (because the brain´s interpretation of the sound = psychoacoustics)

I wanted to say my opinion. I sometimes read your forum from here, from Spain. Sometimes looks like this distortion measurements are a new fashion at DIY to evaluate a loudspeaker, but a speaker has a lot of other important specifications to predict its actual behaviour. 

This is the best DIY car audio forum I have found. Congratulations for your creation.

Best Regards from Spain


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## chipss (Nov 13, 2009)

that defines Psychoacoustics I would say, nice second order harmonics, or any type of boost button, and the way humans hear things...

a system that is pretty darn flat f/R wise, once I heard it was a complete suprise to me....

I would not want my cars speakers to sound as flat as my nearfeilds, 
anymore than I would want to bounce tracks or master with a tube amp...
diffrent tools for diffrent jobs...

I still would like to know more about reading these charts ....and if they mesure second and thrird order harmonics in any way?

edit: I see they do? not sure how I missed that, 




The J said:


> I've heard the term "clinical" used to describe some speakers (well, headphones actually). As far as I could tell the term means that the speaker was "too accurate", removing the fun or joy of listening to anything on them. So then does such a derogatory term imply that there is distortion that we find enjoyable or that music can be distorted in a good way?
> 
> Maybe high-end speakers have simply managed to distort our audio in a good way...? :shrug:


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## sqnut (Dec 24, 2009)

06BLMUSTANGGT said:


> Several audiophiles, as well as myself, will disagree with this statement. In the home, one can build a solid, super dead to the world room, and set up the most expensive equipment known to man.
> 
> In a car that will never happen. First, you have glass, next you have plastic/fiberglass/wood etc. panels that are all going to cause reflections and resonate at weird frequencies. Of course, driving a vehicle 70 MPH down the interstate OR during a torrential downpour will adversely impact the vehicle's listening environment with extraneous noise. So will other vehicles passing you by. What is the average noise floor to overcome in a vehicle again? What about cabin gain?
> 
> Sorry, no one can convince me that a car can be made as good as a home for a listening environment. I won't even get into the theories required for accurate stereophonic reproduction, but I will say that most recordings WERE NOT engineered to be reproduced in a vehicle.


++. Yet car audio can be made to sound really, really good. Sure it will not be at par with high end home audio, but it will come close to home upper midfi, under the right circumstances. Check out the top 5 sq cars. 

Measuring how a speaker sounds based purely on distortion figures, may not be the right way. Point is, there is so much of other crap happening viz, reflections, ambient noises that raise noise floor, cancellations, phase issues and the fact that different frequencies are louder from each side etc etc. Given these inherent issues, does it really matter if the speaker has 10% distortion or 5%? 

The fact that inspite of all this car audio can be made to sound nice is an achievement by itself. Tuning+install far outweigh 'equipment/brand', in car audio.


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## chipss (Nov 13, 2009)

so can I just buy my speakers from wallmart now? sure is cheeper, if I can just get past the cheesy gimmicy looks....

10% ??? feel the same way about your HU and amps? hummmmm


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## chipss (Nov 13, 2009)

now that makes a great point....diffrent cone area ...an apple vs orange...lol




methodsound said:


> Since both drivers were tested at 96db / full range, I would ask if cone area would be a factor? The Sd of the Trius is 36.32cm^2 and the Legatia L3 is 27.33cm^2. The smaller cone would have to play with higher excursion then the larger one in order to reach the 96db mark right?


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## less (Nov 30, 2006)

thehatedguy said:


> Cars are not houses. We have much more problems with our listening environment than a house.
> 
> I wouldn't get too caught up in reading these tests. You may have the ultra wizz engineered speaker...on paper. But it might sound like poop.


Couldn't have said it better...

I'd add that there is no replacement for personal experience - and as a person who has tried a huge variety of respected and some lesser known drivers in my quest for the best sound possible, I'd recommend trying to get into a situation where you can here as many drivers as possible installed in a similar manner as what you plan to do in your vehicle prior to purchase - or do what I did and simply try them all. 

Another good technique is finding a mentor who's tastes you understand and respect... then take their recommendations.

I currently use expensive drivers... and of course people will say that is because of my ego, but I don't think that is the case. I personally installed and tested: Focal K2p and Utopia drivers, Rainbow Platinum and Profi drivers, Hiquphon Tweeters, ID subs, several different varieties of ADS drivers and more, but one only has so much time. To me, it made more sense to trust the recommendations of friends and buy drivers that I'd heard had worked well for others than to spend months/years buying every new hot driver that people got stoked about on the forums for its value... 

I ended up using Scanspeak drivers because they sound the best I've found in my current installation and I am able to set them up using the midrange to cover a huge segment of the spectrum keeping the image intact and stable - a philosphy which I've found to work well for me. Sure, there are trade offs - such as the 12m only having average distrotion ratings - but if you listen to them in a good installation covering a wide range - you will likely agree that the advantages of the setup outweigh the advantage of chosing another driver that might have a little better distortion rating in some test. 

Distortion isn't distortion... it comes in many flavors and is often below the threshold of human hearing anyhow... (and for what its worth - ever since I changed out my old ADS tweeters to a set of Dyn da28afs *widely acclaimed), I've lost all interest in Dyn drivers. Unfair? Perhaps, but that is the way it is for me anyhow =)

Good luck finding something that makes you happy. I found the Rainbow Profi set to be the best all around passive set for the money and for ease of use and while they have their weaknesses, if I had to go simple again... thats what I'd be doing.

Just my 2 cents...


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## diegoejea (May 11, 2009)

Hi less,

To take advantage of your big experience with different drivers, which tweeter is the deffinitive for you?

About the thread, I say that sound quality is measurable, of course. But these distortion measures are not the only ones to predict how a driver will sound! I reccomend you not to assume this, You have to know that the sound of a driver depends on more things! Not only distorsion! (Besides, there are some types of distortion). Is not that simple like people would like...

Dear less, I would appreciate if you say your favourite tweeter!


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## chipss (Nov 13, 2009)

Distortion is what it is, and is defined.

Distortion can be pleasing, even order harmonics’ or not pleasing odd order harmonics,
, cone break up, hummm many things…
but that’s my the perception of sound, and that is also defined, as Psychoacoustics.


But Psychoacoustics do not change what distortion is, I just don’t understand you guys here…

Distortion: Anything that alters the musical signal. There are many forms of distortion, some of which are more audible than others. Distortion specs are often given for electronic equipment which are quite meaningless. As in all specifications, unless you have a thorough understanding of the whole situation, you will not be able to make conclusions about the sonic consequences

psychoacoustics n. (used with a sing. verb) The study of the perception of sound.


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## k-ink (Dec 20, 2009)

I've had loads of expensive systems at home. But now I am back to relatively cheap Dynaudio speakers. I love their relaxed, smooth presentation. After various high end setup's I have no desire to change.


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## jimbno1 (Apr 14, 2008)

I appreciate all the well thought out responses. Obviously there are other factors than distortion when choosing speakers. Freq response, Impedence curves, TS parameters. Since we cannot all listen to every speaker we are interested in, we have to have some way of predicting their performance. 

I agree finding a mentor to guide you is a good idea. But for some of us this forum fills the role of a mentor. 

Yes there are significant challenges inherient in the auto environment. Perhaps the noise floor and reflections in a car renders speaker distortion insignificant. But that does not explain why these same high distortion speakers are just as popular for home use as in car audio. 

As some others have postulated I wonder if some distortion is pleasing to the human ear and enhances the listening process. 

Thanks again for your responses. I think I have learned something.


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## JayinMI (Oct 18, 2008)

One thing I don't seem to have seen touched on (in so many words) is what I've heard referred to as "daddy syndrome."

Much like when people build they're own sub enclosure, and then say "Wow! I'm hearing things I never heard before. This must be better!" 
Doesn't mean it's _right_. Just because you can hear something with brand X speakers you couldn't with Brand Y speakers, doesn't necessarily mean it's better in all circumstances.

As far as the car environment, it seems to me that competition cars are judged in as close a manner of a room in a house as possible. Car running at idle. Not driving down the freeway. Windows closed. 

This is one of the reasons I can't see spending thousands on car speakers for a car I drive everyday. It seems to me that large changes in distortion precentages might not be audible at highway speeds, or in normal around-town driving.

Everyone has their opinions, and you aren't going to change people's minds on most things....it's like Chevy vs. Ford.

Personally, I think people put WAY to much emphasis on specs. Everyone hears differently, so I'd be more inclined to listen to a variety of speakers and see what I thought without looking at the specs.

I generally use the info I find here to get a good idea of the quality of something, and then listen to it for myself. I figure if the general consenus is that something is very good, then it is a good _starting point._ 

It's easier to make good equipment sound good, then crap equipment.

Jay


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## Dryseals (Sep 7, 2008)

In some ways I find this very funny, so many want to down play distortion in the speaker and I'm sure when they look at their amp, they want the smallest number possible.

So what do I look for when building a system? On the amp the same as you guys, got to have those top notch specs. But then why would I settle for not having the same in my speaker.

Distortion does come in many flavors from many sources, but in a sound reproduction device, I would consider distortion our enemy. Any alteration of the original signal is classified as distortion, correct? And in a sound quality forum, I would think that most would be tring to recreate that original sound in it's most purest form, nothing added or taken away. Non-linear distortion being extra freqs added to the original and linear being a deviation from flat.

If I were to come here and post that I think my factory speakers sound just great, I would have folks hammering me from every angle. But that's the stance you're asking me to take when you defend your speakers, the end result, wether the sound is appealing to you or not.

OK, lets say I take that position. But now I have to ask the why's. 
Why care about time alignment. It's a big thing today, one of those little machines can set you back several hundred dollars. And then spend hours trying to set the speakers in a position to give us the best time alignment

Why care about eq levels, enough so that we buy equipment to adjust them and equipment to measure so we can set them? I know we all look at those eqs and say not enough bands, I need that 1/3 octave eq for my needs. The old bass and treble should do me just fine.

If I can't hear certian distortion, then why worry about the amp that produces it, mainly the sub woofer. Xmax is a number many want to toss out there, bigger is better right? But even the manufacturers know that when approaching Xmax, distortion can be well over 10%. But would any of you settle for an amp that advertized [email protected] of 10%., you'd chunk it in the trash. So what's the point of a high dollar amp that doesn't offer any more than an amp at half the price. Can you hear the difference? Most say they can, what's that term.... clean, Hmmm, clean, distortion free. So an amp that has .1% THD you can notice over one that has .001% but can't tell 10% in a speaker so I'm not to worry about it. I'm getting so confused.

I could go on for a long time about this, I've only had forty something years of listening to the logic in the audio world. Your ears can and will lie to you. You can chose to accept it for what it is or strive to make them more honest. The only way to make them more honest is to learn what it is you are listening for and correct that sound. How do you do that, take the time to really listen. I'm lucky, we have a house full of musical instruments, I consider the piano to be the best learning tool, I can't play it but the wife can. If I can tweak my system to reproduce the piano sound faithfully, then I know it's sounding very close to correct. 

So I'm not going to accept a speaker that adds a fair amount of distortion into my system because it will "color" the sound. I like that term "color", the first time I ever heard it to describe a speaker, I got this image of a little kid with crayons creating his work of art on his moms wall. Kind of the way I feel about a speaker coloring the sound. His work of art looks great to him, but his mom is not going to feel the same way.

Bottom line is, we can measure the speaker performance and the manufacturer will give us some of that data, you wouldn't settle for a midbass driver that had a big slump in the spl curve at 100hz. So why should I settle for a speaker that has a high rate of distortion in that same area. You will hear it in some shape or form, the spl curve doesn't show it and you'll spend days trying to figure out were the problem is. You see these posts on a regular basis, my brand X driver does this, and a million responses to help them figure it out, but that's where the distortion measurements come into play. Driver X may have a nice flat looking curve, but the non-linear distortion may be very high in the area he's trying to use them and is changing what it is he wants to hear, for some, they like it, for others they won't.

But knowing where these numbers is the best way to start building a system. Too bad the manufacturers won't publish them but they do know that harmonic distortion in a lot of speakers gives them a nice sound quality that some folks enjoy. But put that piano player in the passenger seat and he'll have visions of a kid with crayons.


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## thehatedguy (May 4, 2007)

The only distortion you should be worrying about in speakers is non-linear distortion. Complex tones and music will mask a lot of distortion artifacts.

And if you are so worried about distortion, you shouldn't be using direct radiating cones/domes in the first place. Compression drivers have distortion levels that are on orders of magnitudes lower than cones/domes.


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## Scott Buwalda (Apr 7, 2006)

I will add to invoke discussion...

Quantify the testing procedure on anyone's third-party website. Is it both accurate and precise? (look up these definitions if you need to refresh your memory) The distortion testing on said third-party websites is almost always done without any crossovers, typically at an amplitude considerably higher than anyone would consider playing these drivers without a crossover, amongst several other variables not being adequately controlled. Example: a 27cm^2 diaphragm driver being played full range, with no baffle, in a non-studio or non-anechoic environment with undefined room modes, with the possibility of resonant modes, undefined power compression and room standards, with no microphone calibration procedure, at 96 dB full range. 

Yes, I believe distortion will be manifested in this type of environment.

Speaker distortion is a misunderstood topic without first understanding the premise of the testing procedures employed.

Put a 3” or 4” driver, any driver, with a highpass at 250 Hz at 24 dB/octave and play it within its intended power band, and watch the distortion plummet to the point of making it virtually an irrelevant topic by comparison of any number of other, more important issues.

Use your ears. Combined with the brain and its library of sounds, the interaural system God gave us all is going to be the most refined testing equipment available to us.

Scott


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## less (Nov 30, 2006)

This is a very good thread on a number of levels and exposes us all to some different ways for us to look at things. I can't speak for everyone, but I surely do change my opinion on things at times when presented with a logical and compelling argument... its called learning and I hope most of you aren't so married to your opinons as JayinMI believes.

One of the points I was trying to make was that everything is relative and when asked to choose between distortion levels and some other factors, distortion in drivers might not be the most important stat. For an example, pick up the autosound 2000 test disc number five and listen to the distortion tracks where they start at .3% and goes to 30% then tell me of its importance compared to other important factors. You might be very surprised and be able to put this more into perspective. (Yes, I understand that this only demonstrates a single form of distortion and that others are more objectionable)

I also believe that we all have our own idea of what sounds good. I'll send a pm to the person who asked about my favorite drivers... but it is strictly my opinion based on my particular preferences, vehicle and installation.

Good discussion.

Less


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## thehatedguy (May 4, 2007)

Dr. Geddes-

"the biggest being my and many others that have shown that nonlinearities in loudspeakers are just not that audible"

"As I said, I can show that the effect is there, I just havn't correlated it with subjective impressions. On the other hand all attempts to correlate nonlinearity to subjective impressions have failed - and thats been tried on many ocasions. Many people just don't want to accept that this is true. Even Klippel has tried to do this kind of correlation and failed. What he uses for his audible demonstrations are gross nonlinearites the type of which no competent designer would ever use. Its not a valid demo."


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## RBeachTL (Jul 21, 2008)

Scott Buwalda said:


> I will add to invoke discussion...
> 
> Quantify the testing procedure on anyone's third-party website. Is it both accurate and precise? (look up these definitions if you need to refresh your memory) The distortion testing on said third-party websites is almost always done without any crossovers, typically at an amplitude considerably higher than anyone would consider playing these drivers without a crossover, amongst several other variables not being adequately controlled. Example: a 27cm^2 diaphragm driver being played full range, with no baffle, in a non-studio or non-anechoic environment with undefined room modes, with the possibility of resonant modes, undefined power compression and room standards, with no microphone calibration procedure, at 96 dB full range.
> 
> ...


What Scott says here is very much in line with my experience. When testing either speakers or amps at the edges of their performance envelope then distortion becomes a limiting factor. What is more important, is the amount of back-off required to achieve acceptable performance. We normally plot distortion (either total or 3rd order) as a function of back-off and we do this for families of frequency responses. Also measuring distortion with tones can be overly pessimistic as real world performance with a complex modulated signal often produces very different distortion outputs.


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## Scott Buwalda (Apr 7, 2006)

RBeachTL said:


> Measuring distortion with tones can be overly pessimistic as real world performance with a complex modulated signal often produces very different distortion outputs.


^ read carefully - the above is a very important observation. I never listen to 0 dBF tones at 96 dB through a 3" cone speaker with no crossover---does anyone else?

Scott


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## chad (Jun 30, 2005)

Scott Buwalda said:


> ^ read carefully - the above is a very important observation. I never listen to 0 dBF tones at 96 dB through a 3" cone speaker---does anyone else?
> 
> Scott


Everyone here seems to think that they do... you gotta set your **** with a DMM Scott, don't you know, all the cool kids to it


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## Scott Buwalda (Apr 7, 2006)

LOL @ DMM. 

Scott


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## lycan (Dec 20, 2009)

careful guys, don't be too quick to dismiss "test tones"

There's a VERY good reason why we use signle sinewaves to test audio equipment. The high-brow explanation is that sinewaves are eigenfunctions of linear, time-invariant systems (i know) ... and the mid-brow reason is that Fourier established (by way of a theorem, kind hard to argue with) that _any_ signal can be expressed as a combination of ... you guessed it ... sinewaves.

This is HUGE. It allows us to test, and characterize, audio equipment (including processors, amps, speakers, etc) with a set of "fundamental" or "basis" signals ... in the form of sinewaves ... without testing each driver (for example) with Lou Reed, Frank Sinatra, Brittney Spears, Pearl Jam, etc etc. And we can feel comfortable that our testing is _still_ comprehensive.

An extension of the same principle, for nonlinearities: imagine a non-linear system to be adequately described by a simple, frequency-independent polynomial (not the case for speakers, ultimately, but it's a start!). It can be shown that a few selected sinewaves will allow us to determine the polynomial coefficients, which means that we've learned all we need to desribe how the _nonlinear_ system will respond to _any_ complex signal, of _any_ amplitude.

The short version is this : we ALL listen to "test tones" ... not one at a time, mind you, but in combination that we call music  If a system doesn't respond well to a single tone, it's hard to imagine that adding more tones will help 

More later ... gotta run ...

P.S. Of course this does NOT mean that I advocate testing a driver outside it's useful frequency band. So the presence of a crossover, or simply restricting the test tones to the appropriate bandwidth (same as crossover) makes infinite sense.


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## Patrick Bateman (Sep 11, 2006)

jimbno1 said:


> I was wondering why the big love for high distortion drivers such as Dynaudio, HAT, and Morel mids, Ribbon tweeters, Maggies, etc. At least based off Zaph's testing of some of these speakers. I know everyone says let your ears decide, but why do our ears (some anyway) prefer distorted speakers?
> 
> It has been some time since I have heard 3-way Dynaudio setup but to tell the truth the last time I did I was completely underwhelmed. The car was professionally tuned by a well respected shop. I can say the same for a buddy of mine's 3-way Morel setup (not professionally tuned). I actually preferred his previous Boston speakers.
> 
> ...


People like high distortion loudspeakers because they sound better.

Here's an example of what I mean:

A few years ago I had an opportunity to "talk shop" with Dr Earl Geddes, and I purchased a flight to Colorado, where he was demonstrating his loudspeakers. I hung out in the demo room for the better part of the weekend, and watched a lot of people listen to the demo. I really think that demo made an impact on a handful of people. For instance, a well known writer for audio magazines named Lynn Olson spent a great deal of time in that demo room, and he's used some of the technology in his own projects. I personally bought a set of those speakers, and I am also using ideas from there on this forum and others.

But here's the funny part - I'd say that over half of the people who listened to the demo dismissed it in a matter of seconds.

And that's the funny thing about low-distortion speakers. They sound odd at first, because we're _accustomed to distortion._ I would even argue that many companies use distortion in the same way that a chef uses spices, to make a speaker sound more "exciting" or "different." (When a signal is distorted it sounds louder by the way.)

But that isn't high fidelity. I personally listen to my speakers for 6-12 hours every day, and there's no way I could tolerate distortion with that kind of regular use.

At the audio show Geddes ran into a peculiar problem, that people often _prefer_ speakers with audible coloration. This problem bugs me too, because I'm always a bit reluctant to demo my car. The system in my car doesn't sound particularly exciting, because it has very low distortion, and basically plays music without getting in the way. But that type of presentation doesn't "grab you by the balls."

Basically, coloration can be very exciting during a three minute demo, but becomes extraordinarily fatiguing over time.


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## Mooble (Oct 21, 2007)

Someone please torture me with some high distortion Revelator or Esotar II drivers all day long! If only I could be so lucky!


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## Patrick Bateman (Sep 11, 2006)

Scott Buwalda said:


> Speaker distortion is a misunderstood topic without first understanding the premise of the testing procedures employed.
> 
> Put a 3” or 4” driver, any driver, with a highpass at 250 Hz at 24 dB/octave and play it within its intended power band, and watch the distortion plummet to the point of making it virtually an irrelevant topic by comparison of any number of other, more important issues.
> 
> ...


Scott,

Here's something which is often overlooked, and can be used to improve the performance of small loudspeakers:

When we build loudspeakers for the home, we typically use VERY rigid enclosures. For instance, I have a set of Polk home speakers that uses cross braced MDF, and the enclosure is as solid as a rock. And these aren't megabuck "audiophile" speakers - they're about $800 a pair. Nothing fancy.

The drivers IN the Polk speakers are also quite mundane. They use a Vifa woofer and tweeter that cost about $40 in bulk.

But in the car audio world, I routinely see people buy drivers that cost five times as much _and then they mount them in a car door._

Simply mounting the speaker in a car door will generate gobs of distortion, because the door panel will flex, adding audible distortion to what you're hearing. Heck, even having junk in the map pocket is a problem. The loudspeaker will vibrate anything attached to the door.

On the other hand, you can take a 3" loudspeaker and cram it into a very VERY small and rigid enclosure, and the sealed box will absorb any vibrations.

The reduction in distortion is measurable and audible, because a small woofer in a rigid sealed box is a better enclosure than a large woofer in a leaky car door. I think that people overlook the fact that a low distortion woofer in a crummy enclosure can be bested by a mediocre woofer in a rigid enclosure. IE, the enclosure is as important as the woofer.


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## pionkej (Feb 29, 2008)

Patrick Bateman said:


> People like high distortion loudspeakers because they sound better.
> 
> Here's an example of what I mean:
> 
> ...


I don't understand how you can acknowledge that there are varying ways of enjoying one thing (see blue) and then say it is wrong (see red). 

I was actually about to make a comment bringing examples from other fields. You are right about cooks doing something to add their "signature" to a normal meal. By your own logic, a food critic should not enjoy that meal, because it isn't the meal in it's TRUEST FORM. So they grade down for seasoning and spices and unflavored baked chicken scores a "10". 

So why can't speaker companies add their "signature"? We can consider ourselves audiophiles because strive to reproduce music accurately, but at some point, our enjoyment must come into play too. Why is it wrong that we do that? You clearly don't enjoy it, but others may. 

Personally, I like the "warm" and "smooth" sound that is produced by Morel speakers. I know this is coloration from the speaker, but I enjoy the sound of it. I did not buy them for the name. In all honesty, I would bet that for about 70% of us, outside of this forum, if we said we ran morel/dynaudio/hertz/hybrid audio/rainbow/focal/etc. most people wouldn't know if that were expensive or cheap and would just wonder why we didn't run JL (DISCLAIMER: there is nothing wrong with JL either, it is just the "gold standard" locally by the masses for high-end).

Lastly, I enjoy my chicken lightly pan-fried with a blend of bread crumbs and parmasean cheese for breading and coarse ground black pepper and oregano for seasoning. I am probably wrong about that too, but I enjoy it since it tastes good TO ME.


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## Dryseals (Sep 7, 2008)

thehatedguy said:


> Dr. Geddes-
> 
> "the biggest being my and many others that have shown that nonlinearities in loudspeakers are just not that audible"
> 
> "As I said, I can show that the effect is there, I just havn't correlated it with subjective impressions. On the other hand all attempts to correlate nonlinearity to subjective impressions have failed - and thats been tried on many ocasions. Many people just don't want to accept that this is true. Even Klippel has tried to do this kind of correlation and failed. What he uses for his audible demonstrations are gross nonlinearites the type of which no competent designer would ever use. Its not a valid demo."


I've read Dr. Gedde's work, I'm not all that impressed with his findings and his papers leave little to shall we say, back up his work. Too many variables that he does not address.
So to make it a little clearer, as I said before, hearing is learned. If you learn the particular sound of an instrument as in playing it for years, then you will notice the non-linear distortion from the speakers.
Those extra little freqs do make a speaker seem brighter and for the most part, folks will enjoy them, it's pleasing to the ear. But if you are familiar with the sound they are trying to reproduce, you may or maynot be happy.

If you truely buy into Dr. Geddes work then there is no need for gear that can reproduce top notch sound. He kind of leans towards the Budwieser taste of building speakers, those for the masses.


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## Patrick Bateman (Sep 11, 2006)

pionkej said:


> I don't understand how you can acknowledge that there are varying ways of enjoying one thing (see blue) and then say it is wrong (see red).
> 
> I was actually about to make a comment bringing examples from other fields. You are right about cooks doing something to add their "signature" to a normal meal. By your own logic, a food critic should not enjoy that meal, because it isn't the meal in it's TRUEST FORM. So they grade down for seasoning and spices and unflavored baked chicken scores a "10".
> 
> ...


Colored speakers can be fun, sure. It's one of the conundrums of audio isn't it? What colorations are offensive, and which ones are not?

While I was building the "high fidelity" system in my Accord I maintained a second set of full-range speakers in the kick panels, a $30 set of Aura Sound full-ranges. I mean, if you're starving it's smarter to eat a Big Mac RIGHT NOW than wait a year to eat filet mignon. The Aura Sounds can't compete with the stereo that I'm working on, but I'd rather use them temporarily than listen to a half-finished system.

Despite high levels of harmonic distortion, I was satisfied with the sound, because it did a few things very well which I like. (Soundstaging, reasonably good frequency response, no huge peaks or dips.)

That's the problem with focusing on harmonic distortion exclusively. It's just part of the puzzle.


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## SoundChaser (Apr 3, 2009)

I say leave the coloring of the music to the musicians/artists that created the music. Not by other means like speakers or even studio engineers. :beatnik:


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## Mooble (Oct 21, 2007)

SoundChaser said:


> I say leave the coloring of the music to the musicians/artists that created the music. Not by other means like speakers or even studio engineers. :beatnik:


You realize how absurd this is, right? 

It's bad enough trying to get your car to sound good in the first place. The car itself is coloring the sound more than anything else in your system. Leave the studio monitors for the dedicated listening rooms where they will happily sound dull and flat.  Arguing sonic or artistic purity in a car environment is silly.


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## Hernan (Jul 9, 2006)

I have a question.
Some big names brands, Morel, Dyn, DLS, HAT, are defined in this thread as "high distortion driver that sound nice to most people".

What do they have in conmon? What I see is the use of well damped cones materials, Poly, Paper, etc, and good but not exceptional motors.

Perhaps the word is forgiving, a good thing in a car install. They trade ultimate precission for easy to use.

I feel that bit of harmonic distortion is not as offensive as a wild breakup mode.

Recently I swap my midranges from RS52 domes to the Bamboos cones.
The domes have lower distortion on paper but the cones easier to tune and easier to listen. I missed the dynamics of the domes but after 3 year living with them I have to accept that they are not easy to get right in my car.

I used to have a pair of JBL 4311 Control Monitors at home. When I bought them, I live at a big appartment with heavy courtains, very tall ceilings, I sit 6 meters away from them (3ways, 12+4+1) and they sound great! 
Today I live in a small place, acoustical much more live. I end selling the JBLs and getting some two way towers using Vifa drivers. They don't have the flat response, great bass and low distortion mids of the monitors but they image better, sounds better at low to moderate volume, they are much more forgiving with not so good recordings, they are better suited to the small space.


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## MiniVanMan (Jun 28, 2005)

First we need to discuss the definition of "Sound Quality", or "SQ", which is a term that now drives me nuts.

Is sound quality based on the individual's perception, or is it based adding as little distortion or coloration to the original signal? In other words is it subjective, or is it measurable?

I can go through this thread and practically pick out each individual's understanding of sound quality, and they fall into one of those two categories.

Bateman is of the latter group, while Buwalda relies on the first group. Neither are wrong, when fundamentally it comes down to being happy with your end product. 

However, don't dismiss out of hand what Bateman is saying. You're preference may create a bias that will immediately dismiss a better performing loudspeaker. It's part of the training of our ears.

If you prefer the sound of HAT driver though, that's fine. There's a definite coloration to HAT drivers that you may prefer. Coloration is distortion though. Again, it comes down to being happy with the end product, all debates aside. It really comes down to being educated in your preferences. 

There's another little snippit Bateman said where distortion is audibly louder. Studies have been done where the VAST majority of listeners will pick out the *louder* speaker as having better sound quality. Same is true with amps. All ratings aside, the amp that actually puts out the most power will be perceived as having the best "sound quality". I personally fall into this group. I enjoy loud. However, I need to be careful when trying to achieve that, that I really focus on NOT exciting non-linear distortion, as that's fatiguing.

So, do I love high distortion drivers? Not at all. All drivers will distort as Buwalda mentioned. Proper system design, a clear understanding of your goals go a long way toward achieving a high quality system that delivers both the output and sound you prefer. This is why measuring your own speakers is of critical importance. Third party guys help immensely, as has been pointed out, manufacturers just don't provide much information.


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## Patrick Bateman (Sep 11, 2006)

MiniVanMan said:


> First we need to discuss the definition of "Sound Quality", or "SQ", which is a term that now drives me nuts.
> 
> Is sound quality based on the individual's perception, or is it based adding as little distortion or coloration to the original signal? In other words is it subjective, or is it measurable?
> 
> ...


To be honest I'm not in one camp alone. I'd compare it to the difference between a photograph and a painting. Each has it's own purpose, and a well done painting can be more exciting than the real thing.

For instance, the Wall Street Journal doesn't use many photographs. It uses illustrations for the majority of it's articles. And in the limited medium of newsprint, a well done illustration works better than a poorly reproduced photograph.

Having said that, I find colored speakers _fatiguing._ Not boring, or offensive, or pointless. They have their uses. But I can't listen to them for long. I find a very low distortion speaker that does everything well isn't very exciting to listen to, but it "gets out of the way" of the music. Also, I listen to music at really absurd levels. That makes distortion a heck of a lot more offensive.

Again, I think the lure of distortion is that it can sound "exciting" or "lively" or simply "louder."


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## MiniVanMan (Jun 28, 2005)

Patrick Bateman said:


> To be honest I'm not in one camp alone. I'd compare it to the difference between a photograph and a painting. Each has it's own purpose, and a well done painting can be more exciting than the real thing.
> 
> For instance, the Wall Street Journal doesn't use many photographs. It uses illustrations for the majority of it's articles. And in the limited medium of newsprint, a well done illustration works better than a poorly reproduced photograph.
> 
> ...


I understand that you're not in one camp exclusively. All I was saying is that distortion is measurable, and once you understand your personal preferences, you can measure a speaker, and it's sound quality.

Ultimately, it always comes down to subjective analysis as a final determination, but objective evaluation and testing shortens the journey to a satisfactory final result.

I prefer loud insanely loud as well. Lower distortion drivers, and utilizing them within an appropriate bandwidth allows for more distortion free output. Again, all drivers will distort eventually. I'm not horribly opposed to second order harmonics though.


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## m3gunner (Aug 6, 2008)

Jay, you ROCK... couldn't have said it better myself.

And, as usual, MiniVanMan steps up and hits it out of the park.

Lower distortion is preferable, but it's not the only criteria by which people choose drivers. If that were the case, we'd all have Velodyne servo subs to get that 0.05% THD driver out of the way...


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## 89grand (Nov 23, 2006)

All I know is that everyone better bow down to HAT...well except me.


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## dkh (Apr 2, 2008)

89grand said:


> All I know is that everyone better bow down to HAT...well except me.


Errr... ok :laugh:


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## Scott Buwalda (Apr 7, 2006)

At the end of the day, there are many things working against us. The mechanics alone in any given vehicle throws any audio "laws" under the tires. Which brings me to a point: far, far too often car audio enthusiasts get swept up in electronica, and don't spend even 1/100th of their effort on mechanics. Most think that one layer of sound deadening on a door, with a speaker clamped tightly to the metal, behind a plastic OEM grille that's an inch too small in diameter is satisfactory. And for 99.9% of folks, it is. But there's that 0.1%, like me, and perhaps a few that have contributed to this thread that understand mechanics, and understand that this isn’t good enough. Anything between your tympanic membrane and the speaker is a distortion-inducing process. _Even your body. Even the size and shape of your head._ It's a stacked deck of cards we play with, riddled with mechanical and acoustical-mechanical pitfalls. So it's our goal to minimize the mechanical effects, not with electronica per se, but with better mechanics. 

With a properly filtered speaker, any speaker, operating within its power band, speaker distortion is definitely not even in the top-20 of worrisome issues in a car audio environment. The proof is in precise and accurate anechoic testing, with electronic filtering suitable for the driver (in the case of this discussion, high-pass), operated within its power band. We all know through BL based THD testing that as excursion increases, so does a commensurate amount of distortion. If a 3" midrange is allowed to hit a peak to peak excursion of 6mm, *then yes, there will be distortion*. But a 3" midrange filtered at say, 250 Hz at 24 dB/octave, allowing a mere 1mm of peak to peak excursion will have its distortion figure plummet to non-issue. I'd say easily less than 3% based upon my experience with properly-filtered Legatia speaker systems. Certainly, if you want your 3” speaker playing from 20 Hz and up at 96 dB (99 dB as a pair) without any other speaker playing, as these third-party tests have been conducted, then you must live with the 10 or 20% distortion. But those of us in the real world, that actually cross our stuff over appropriate for the driver’s parameters, do not need to worry about a few tenth of a percent of distortion _when there are SO many other issues that confront us_: step response, baffle response, baffle resonance, power compression, enclosure resonance, sound wave refraction, early reflections, late reflections, relative phase, absolute phase, and the list goes on and on.

If you think you can hear driver distortion in a car, and everything is set-up properly, such as acoustical filters, you’re likely not hearing the drivers at all, but the excitement modes, resonances, phasing distortion and other mechanical phenomenon that are occurring as a result of the speakers playing.

Scott


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## SSSnake (Mar 8, 2007)

Scott,

I think that the vast majority of posters appreciate your contributions to this forum. I particularly appreciate the involvement by vendors such as yourself and would like to see much more vendor involvement. Furthermore I agree with everything you mentioned in the post above. However the main question is when trying to make a speaker purchase why would someone pick a higher distortion driver over a lower distortion driver... I agree with your assertion that there are other things you must consider (NPDang was/is a huge advocate that the room had more effect on the sound than any other system component).

IMO - Customer support is definitely one of the things that people should consider. I don't think anyone would argue that your customer service is excellent. If you call Peerless and ask them why the SLS 8" is performing poorly in your door, see what happens. Can you say dial tone?

Additionally, you have done an excellent job developing a support system with the hybrid audio team. The team appears to be very cohesive and supportive of each other and other hybrid customers. Beyond this you have gone out of your way to educate the car audio community (many thanks).

Beyond these assertions what, in your opinion and without revealing any proprietary info, makes the HAT drivers well suited for automotive apps?


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## BigRed (Aug 12, 2007)

89grand said:


> All I know is that everyone better bow down to HAT...well except me.


oh, so you're bowing down to morel and dynaudio  the other "high distortion" speakers


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## m3gunner (Aug 6, 2008)

SSSnake said:


> However the main question is when trying to make a speaker purchase why would someone pick a higher distortion driver over a lower distortion driver...


I think Scott covered this above... the reason someone might choose a driver with higher distortion is because distortion is a relatively minor player in the car when other factors are taken into consideration.


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## SSSnake (Mar 8, 2007)

And I am suggesting that he identify some of those "other factors" which are unique to his products.

BTW - I do think there are some things that distiguish his drivers from others... I am just suggesting that he discuss those attributes.


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## Scott Buwalda (Apr 7, 2006)

SSSnake: thanks for your generous and kind words. It is greatly appreciated.

Honestly, there's nothing proprietary about a few of the HAT products. Yes, there are patentable items on several of my tweeter designs, and on the future L3 and L6 Pro, but I haven't gone down that road because it's an expensive and time consuming process that really doesn't mean a hill of beans at the end of the day with sweat shops in Malaysia reverse-engineering your product...

That being said, the stuff that isn't proprietary is pretty straight forward, and it's what I "believe in." Everything from cone type, geometry, and low moving mass, to low mass, appropriately sized voice coils, using no traditional dome diaphragms, to phase plug geometry, reverse roll high-loss natural rubber surrounds, wide-bandwidth operation (probably the most important function) and where necessary, Faraday shorting rings or caps (such as in the L4). Many of today's manufacturers are in a race to see who can produce the worst cone break-up mode midrange using whatever the vogue exotic material is for that year, and as a result, are pushing the intermodulation distortion limit of their tweeter designs with ridiculously low tweeter crossover points to filter out inherent flaws in the midrange designs, and split vocal frequency sound stages in a car. It sounds good on the board, why does it sound terrible in the car when the midrange and tweeter are separated by more than one quarter wavelength at the crossover frequency?  It's not magic, just common sense acoustics and understandintg musical theory. 

What could be a better hobby than combinign cars with music? Seriously!

Scott


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## katodevin (Feb 14, 2008)

Scott Buwalda said:


> That being said, the stuff that isn't proprietary is pretty straight forward, and it's what I "believe in." Everything from cone type, geometry, and low moving mass, to low mass, appropriately sized voice coils, using no traditional dome diaphragms, to phase plug geometry, reverse roll high-loss natural rubber surrounds, wide-bandwidth operation (probably the most important function) and where necessary, Faraday shorting rings or caps (such as in the L4).


Hi Scott,

I notice both in your above quote as well as manifested in your designs that you believe having wide-bandwidth operation as being very very important in establishing coherence for the essential midrange frequency range. I can see this being very important for a 2-way system, where you're asking 2 speakers to cover a huge range. 

However, in a 3-way system, do you feel that engineering wide-bandwidth drivers is as important? The drivers obviously have to cover less of the frequency band as there are 3 of them. More specifically, your L3/L4 speakers have shown the ability to play at LEAST up to 5k easily. Is there any point in engineering a tweeter to extend down to 2k to mate with this? 

Do you give anything up, design or performance wise, in creating a wide bandwidth tweeter, when you could focus on creating a more narrow bandwidth tweeter to mate with the L3 speakers?


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## Patrick Bateman (Sep 11, 2006)

Scott Buwalda said:


> Many of today's manufacturers are in a race to see who can produce the worst cone break-up mode midrange using whatever the vogue exotic material is for that year, and as a result, are pushing the intermodulation distortion limit of their tweeter designs with ridiculously low tweeter crossover points to filter out inherent flaws in the midrange designs, and split vocal frequency sound stages in a car. It sounds good on the board, why does it sound terrible in the car when the midrange and tweeter are separated by more than one quarter wavelength at the crossover frequency?  It's not magic, just common sense acoustics and understandintg musical theory.


Ugh, I wish more people would GET THIS.

It's completely infuriating to see everyone in audio obsess over the frequency extremes. It is SO EASY to design a sub that can play to 20hz in a car, or a tweeter that can get up to 20khz.

Everyone is so OCD about bass and treble, and then they come on the forum wondering why their systems sound like ****.

_Maybe it's because your midrange is coming from eight different points in your car? Ya think???_

If I wasn't running Unity horns I'd likely be running something like what you describe... The Unity is simply a way to approximate the same thing, but with higher power handling and efficiency.

IE, they're both a "point source."


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## Scott Buwalda (Apr 7, 2006)

katodevin said:


> Hi Scott,
> 
> I notice both in your above quote as well as manifested in your designs that you believe having wide-bandwidth operation as being very very important in establishing coherence for the essential midrange frequency range. I can see this being very important for a 2-way system, where you're asking 2 speakers to cover a huge range.
> 
> ...


Two-way or three-way, it's equally important. Physics don't change just because you have a dedicated midbass. Yes, things get more complicated, but physics, and MUSIC stays the same. The reality is that the vocal frequency spectrum is plus or minus 180 Hz to 6,000 Hz, fundamentally speaking. We'll stick with that as a good working definition, but is highly dependent on the size and shape of your own head and the size and geometry of your ear waveguides. That's a discussion for another day!  Right, so 180-6,000 Hz is where we really, really do need to at least make an effort to have one speaker play this band. And if it's two speakers, such as a midrange and tweeter, that they be separated by no more than 1/4 wavelength at the crossover frequency. Simple physics. 

So in a two-way, the midbass needs to be spectacular, and cover the majority of this band (a difficult proposition without introduction of cone break-up modes, beaming/directionality, and a slew of other problems). It can be done, successfully. But a three-way is no different. The midrange needs to cover this spectrum, and honestly has a much easier time doing it, because the midbass is there reinforcing the bottom octave or two. Therefore IMD drops, power handling increases, and therein is the merit to a three-way system.

The final question is "do you give anything up, design or performance wise, in creating a wide bandwidth tweeter." The answer is usually yes. The race is on by virtually every manufacturer (except HAT and perhaps a few others) to build large diameter, heavy moving mass tweeters to eek every last ounce of bandwidth out of them. The result is an industry currently predisposed to having to cross tweeters over extremely low to both make-up for midrange/midbass shortcomings, and get that ever-important low resonance frequency as a certain calling card. The reality is that as moving mass increases and diameter increases, polar response worsens, the bandwidth shifts downward, and listener fatigue generally increases because of the IMD being carried by the tweeter and its limited suspension compliance. No longer are these large diameter tweeters really good at producing treble, especially to 20,000 cycles. Look at any 28mm or 32mm tweeter at 30- or 60-degrees off axis from 12,000 Hz and up. That’s my point. They’ll work on a board, but may not work so well in a car. That’s also why I’ll never build a huge diaphragm, heavy moving mass tweeter because they frankly usually suck at producing treble and have terrible polar response. The answer to your question, at least as far as Hybrid Audio is concerned, is making two different types of tweeters: a low-resonance tweeter a high-resonance tweeter. There are obvious benefits to both tweeters and can be used at the end-user’s discretion to achieve different goals.

Scott


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## jimbno1 (Apr 14, 2008)

Well at least I know part of my problem with my speakers is my huge mishapen head. I knew it makes it difficult to get a date on Sat night, and that I scare small children and animals. But who knew it affected my car stereo.


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## katodevin (Feb 14, 2008)

Scott Buwalda said:


> Right, so 180-6,000 Hz is where we really, really do need to at least make an effort to have one speaker play this band. And if it's two speakers, such as a midrange and tweeter, that they be separated by no more than 1/4 wavelength at the crossover frequency. Simple physics.


From my initial listening impressions of the L3 i just picked up, I TOTALLY agree on the need for a wide bandwidth midrange speaker to cover this range. Made a large difference for me. 

My question was more geared towards the other 2 speakers in a 3-way setup. What is the need for wide bandwidth midbass/tweeters? The midbass will only need to play up to ~ 300hz, and the tweeter will only need to play down to ~5000hz. So why the need/race to produce midbasses that play up to 3000hz, and tweeters that play down to 2000hz? 

For example, the L6 midbass is designed to play up to 5000hz. I have no doubt that it would perform well in a 3 way setup playing up to ~ 300hz, but would a midbass driver designed for a narrower bandwidth do better in this case?

With having just picked up the L3's, I am looking into picking up some new tweeters to mate with them, and I notice that a lot of tweeter's main "strengths/selling points" is that they extend down low, which I don't care about at all anymore now that I have a point source driver to play most of the bandwidth I need.


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## MiniVanMan (Jun 28, 2005)

Scott Buwalda said:


> Two-way or three-way, it's equally important. Physics don't change just because you have a dedicated midbass. Yes, things get more complicated, but physics, and MUSIC stays the same. The reality is that the vocal frequency spectrum is plus or minus 180 Hz to 6,000 Hz, fundamentally speaking. We'll stick with that as a good working definition, but is highly dependent on the size and shape of your own head and the size and geometry of your ear waveguides. That's a discussion for another day!  Right, so 180-6,000 Hz is where we really, really do need to at least make an effort to have one speaker play this band. And if it's two speakers, such as a midrange and tweeter, that they be separated by no more than 1/4 wavelength at the crossover frequency. Simple physics.
> 
> So in a two-way, the midbass needs to be spectacular, and cover the majority of this band (a difficult proposition without introduction of cone break-up modes, beaming/directionality, and a slew of other problems). It can be done, successfully. But a three-way is no different. The midrange needs to cover this spectrum, and honestly has a much easier time doing it, because the midbass is there reinforcing the bottom octave or two. Therefore IMD drops, power handling increases, and therein is the merit to a three-way system.
> 
> ...


You mean, it really comes down to physics? 

Scott, I would be soooo much more friendly to the people around the forums that rave about your products if I saw them actually implement what you just said.

Instead I see installations that fly in the face of sound physics in the name of owning HAT drivers that supposedly "fix" these problems.


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## lycan (Dec 20, 2009)

some good info in this thread, but also some ... let's say, *dated* ... info as well.

it's OK, Scott is a friend of mine (Jeff S. in Austin, Mr. Buwalda, back from the dead  ) and i know he doesn't mind me challenging him now & then 

First, we've already covered the value of test tones. We all listen to them, everyday, in Fourier combinations we call music. And, as basis functions, they are invaluable tools for evaluating both linear, and nonlinear, systems ... thereby serving as great tools for _predicting_ the behavior of elements subject to very complex waveforms. That's what science is all about 

Second, surely nobody is suggesting that we characterize drivers outside their useful band. CERTAINLY, we may _stress_ drivers to help DETERMINE their useful band, but nobody is seriously evaluating, and comparing, how well 3" drivers perform in the sub-bass region!

Third, and yes this point is hotly debated, there's that old concern that we shouldn't separate drivers by more than 1/4 wavelength (measured at crossover). I understand where this comes from, very well, but it's incomplete ... and often, not accurately applied. The real story is this : IF drivers are time aligned, AND their placement is determined in conjunction with how the ear/brain localizes different frequency bands, there's no reason why drivers can't be placed far apart. The ear will simply have no way of telling.

Case in point : a tweeter up high, and midrange down low ... separated by more than 1/4 wavelength at crossover. Let's say the drivers are time aligned (trivial these days) ... so the wavefronts launched by the drivers arrive at the ear at the same time, and the acoustic combination, through the crossover, occurs at the ear just as if the drivers were coincident. How can the ear possibly tell that the midrange is below the tweeter? It's easy to prove, easy to demonstrate, and it's quite well documented, that we don't recognize height cues until the treble. So the ear simply has NO WAY to determine that the midrange is mounted low, well _below_ the tweeter (it's a completely different story, of course, if the midrange is _laterally_ displaced from the tweeter). And no, you won't often find such discussions in the home audio realm ... simply because the home environment has not forced the enthusiast to understand localization as well as the more hostile car environment.

My view is this : don't worry so much about crossovers in critical bands (and surely, the human voice is a critical band of extreme interest). Instead, worry more about placing drivers in a manner consistent with how the ear _localizes_ sound 

Finally, should we worry about a couple percent distortion from drivers, when there really is more to worry about in a car? This argument is perched on quite a slippery slope ... why worry about distortion from amplifiers? Why worry about noise floor in your signal processing chain, when the noise floor in a car is so damn high? Why worry about frequency response, or transient response, in such a miserable, god-forsaken environment? There's two answers, i think : first, some of the nastiness in a car is, to put it loosely, _uncorrelated_ with the music we're playing ... and, much of what _is_ correlated, finds that correlation in widely _separate_ frequency bands (obnoxious sub-bass vs. delicate midrange, for example) ... and the ear is surprisingly good at distinguishing (and often, ignoring) uncorrelated junk from closely-correlated junk. And second, any true car audio enthusiast will endeavor to improve each & every aspect of the reproduction (certainly attacking the low-hanging fruit first) until a level of satisfaction is achieved. Ultimately, then, a few percent of distortion from _any_ element, if it's above the audibility threshold, must be open to scrutiny.

P.S. I'm really NOT arguing against great 3" vocal drivers (3" drivers that can cover the entire vocal range) ... i'm just arguing that there's no fundamental reason (in physics, acoustics, signal processing, etc.) why equally great results can't be obtained with a _different_ suite of drivers 

EDIT :

P.P.S. Honestly, there _is_ an argument in favor of point source drivers, EVEN given everything i've said above. But, in my humble view, it can't be appreciated until the above points about time-alignment & localization cues are fully grasped  not trying to be coy, just logical.


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## SSSnake (Mar 8, 2007)

Lycan, Werewolf, Jeff;

I agree with the TA statements and their effects on localization if you are making a two dimensional approximation. However, in a compact and reflective environment like a car I would think the power response of two co-located drivers would look different than the power response of two dispersed but TA'd drivers. This presumably could be EQ'd out for a single listening position but would definitely make tuning... more fun?!?


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## thehatedguy (May 4, 2007)

HLCDs for the win!


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## SSSnake (Mar 8, 2007)

Uniform (or at least more uniform) power response is the main reason I am looking at waveguides


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## lycan (Dec 20, 2009)

SSSnake said:


> Lycan, Werewolf, Jeff;
> 
> I agree with the TA statements and their effects on localization if you are making a two dimensional approximation. However, in a compact and reflective environment like a car I would think the power response of two co-located drivers would look different than the power response of two dispersed but TA'd drivers. This presumably could be EQ'd out for a single listening position but would definitely make tuning... more fun?!?


Yes, you are quite correct.

If you are in free space, absent of reflective surfaces, there's simply no way for the ear to distinguish, for example, _vertically_ displaced mids & tweets (if time aligned). This is not limited to two dimensions, however ... the argument applies to all three (four, if we include time) 

HOWEVER, when we introduce the possibility of reflections, and _only_ then, there exists the distinct possibility that a reflective surface is placed such that the arrival time of reflections is different for the two displaced drivers (which would not happen for point sources). So yes, we must step into power response to find the consequence of (intelligently) displaced drivers. But even here, the concept of "power response" is a vast over-simplification to describe the sonic consequences of reflections (near, far, frequency-dependent, etc ... all with attendant comb filtering possibilities).

All things considered, personally, i would not be so enamored with "point source" drivers, so as to disregard other driver combinations ... even intelligently displaced ... in a car. Again, not to say that i would be un-impressed with a kick-ass 3" driver to cover the vocal range. BUT ... back on point ... I would also be interested in the large-signal distortion performance of that driver, down near 300 Hz !!!


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## Scott Buwalda (Apr 7, 2006)

Back from the dead! Welcome Jeff!

Its fun debating with you my friend, because I know the discussion won’t deteriorate into something ridiculous or idiotic.

Jeff, you make several good points, and I feel what you have said enhances the theorems exposed in my posts (such as ¼ wave theory). And believe it or not, I agree with you (reference how many cars I have built with tweeters on a-pillars and midranges/midbass down low). But it gets dicey in that critical band, the vocal spectrum. My main theory, which has suited me well, are wide-band midbass or midrange drivers covering as much, if not all of the vocal spectrum. Then, tweeter location is only critical for allowing the user to interpret stage boundaries (high and wide the tweeters shall go). 

In my blue collar testing, a tweeter and midrange combo crossed lower than about 5,000 Hz, and placed more than ¼ wave at the crossover point from each other (such as midrange in the kicks, and tweeters in the pillars) becomes audible with respect to height and location, even with fancy processor tweaking. Perhaps it’s the size, shape, and diameter of my head, or the geometry of my ear wave guides. I can usually hear an a-pillar tweeter crossed into the vocal spectrum, even in the most tweaked cars using sophisticated time domain adjustment. What happens for me is a split stage where high-vocal information is coming from one location, and low-vocal information is coming from quite another. 

Electronic time delay, as you have suggested, can only do so much, since we are combating not only differences in speaker location and relative distances form the ear, but also less-definable issues such as speaker transient response, polar response, and frequency-dependent group delay, as well as a slew of other deleterious phenomenon in a car, such as power compression manifested as IMD, room modes and modal response, spacial nodes and antinodes, and mechanical phasing distortion, all courtesy of the highly-reflective environment we are listening within. Then you have to consider time delay with respect to the order of crossover you use, as well as crossover underlap comb filtering, as well as mechanical (reflective) comb filtering. Then you add the highly-variable speaker directivity with differently-sized diaphragms, and the interaction of diaphragm size, shape, and materials with respect to polar response. Then you add first, second, and third-order reflections. 

In my opinion, simple electronic time alignment cannot, and never will be the cure for speakers crossed over within the vocal spectrum, that are separated by more than ¼ wave length at the crossover point. It involves luck more than anything else, considering the circumstances, than the use of time domain adjustment as a fix-all. If you _must_ cross a tweeter into the vocal spectrum, then do yourself a favor and put them close to the mid and align the mechanical zero delay plane. My opinion. 

It all comes back down to one thing: OPTIMIZE MECHANICS.

Using a wide-band midrange negates many of the above concerns, leaving only IMD "Doppler" as a potential concern. Fortunately for us, Doppler is the least offensive distortion, and we hear it in every day lives; it's all around us. It's a trade-off, but in my mind using a nice 4" wide-band removes far more variables than "chancing" tweeters playing in the vocal spectrum and relying on electronic time domain adjustment, especially if they're separated from the mid.

I’ll look forward to your reply. I am off for CES in a few hours, so it might not be till next Monday when I can reply.

Scott


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## chad (Jun 30, 2005)

thehatedguy said:


> HLCDs for the win!


sure, in your house or in a concert venue


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## lycan (Dec 20, 2009)

Scott Buwalda said:


> Back from the dead! Welcome Jeff!
> 
> Its fun debating with you my friend, because I know the discussion won’t deteriorate into something ridiculous or idiotic.
> 
> ...


A vertical separation, with a crossover at 5kHz, absolutely _will_ be a problem. The only height cues available to humans are a function of the outer ear shape & size, which means that height cues may begin somewhere around ~ 2-4kHz. Any drivers placed _low_, which are playing up to ~ 2-4kHz, will be localized down low ... and the separation to the tweet will be recognized.


> Electronic time delay, as you have suggested, can only do so much, since we are combating not only differences in speaker location and relative distances form the ear, but also less-definable issues such as speaker transient response, polar response, and frequency-dependent group delay, as well as a slew of other deleterious phenomenon in a car, such as power compression manifested as IMD, room modes and modal response, spacial nodes and antinodes, and mechanical phasing distortion, all courtesy of the highly-reflective environment we are listening within. Then you have to consider time delay with respect to the order of crossover you use, as well as crossover underlap comb filtering, as well as mechanical (reflective) comb filtering. Then you add the highly-variable speaker directivity with differently-sized diaphragms, and the interaction of diaphragm size, shape, and materials with respect to polar response. Then you add first, second, and third-order reflections.


Transient response, and frequency-dependent group delay are nothing but subsets of the _complete_ frequency response (magnitude and phase, as functions of frequency). In other words, show me magnitude versus frequency, and phase versus frequency, and i'll show you the transient response (Fourier Theorem). Show me the phase response alone, and i'll show you the group delay (group delay is identically the first derivative of phase wrt frequency). None of this, in itself, detracts from the fact the humans can't hear height until the treble  Any well-designed crossover will absolutely comprehend magnitude as well as phase, thereby also completely comprehending transient response as well as group delay. And, in this category, time alignment can compensate for distance displacement ... as long as that displacement accounts for the ear's ability to localize, of course. In short : In free space, it's impossible to tell a tweeter separated from a midrange IF:

- the separation is vertical
- the crossover is below the critical range for height cues (function of outer ear)
- the drivers are time aligned

This principle will hold true for any transient response or group delay function you want to throw at it  The ear simply has no way to tell. Of course, if the crossover is poorly designed without regard to phase, you may hear some weird response issues in the vocal band (cancellation creating magnitude dips, for example), but that's a separate issue from physical driver displacement.

HOWEVER, once we start considering reflections, there absolutely is (or, can be) situations where driver displacement can be recognized. But that's a big, complex topic that is only hinted-at by power response. Case in point : put a good waveguide on the tweeter to control it's directivity in the cabin, thereby side-stepping a lion's share of tweet reflections. I'm willing to bet, once again, that physical separation of the mid & tweet becomes hard to notice (assuming all the above points are met). Remove the waveguide, and you can perhaps induce so much comb-filtering in the treble, that physical separation of the mid & tweet becomes the _least_ of your problems. Those comb nulls won't show up in the tweets power response  A bad crossover will still be heard, of course, no matter how close the drivers are 


> In my opinion, simple electronic time alignment cannot, and never will be the cure for speakers crossed over within the vocal spectrum, that are separated by more than ¼ wave length at the crossover point. It involves luck more than anything else, considering the circumstances, than the use of time domain adjustment as a fix-all. If you _must_ cross a tweeter into the vocal spectrum, then do yourself a favor and put them close to the mid and align the mechanical zero delay plane. My opinion.
> 
> It all comes back down to one thing: OPTIMIZE MECHANICS.
> 
> ...


Time alignment is, of course, NOT a cure-all. But it's one tool in our arsenal, in this crappy environment.

My advice : it's easy to list all the things we have going against us in audio, especially in a small, reflective environment where we don't even sit in the center. We can "lump" all the problmes together, and then offer some words of wisdom that hint at solutions. But that's no help 

It's much more meaningful, in my view, to _separate_ the issues, one-by-one, and describe what helps each issue, and what doesn't. Only then do we have a structured, scientific approach to problem solving  certainly, many issues are related, but we can recognize that along the way. For example :

- start with a well-designed crossover for point-source drivers in free space. Such a beast will comprehend magnitude as well as phase, thereby comprehending transient response as well as frequency dependent group delay. If this crossover happens to be right in the vocal range, and is poorly designed, it WILL be heard, even in this simple case.

- next, vertically displace the mid & tweet ... still in free space. How much of that displacement will the ear hear? How much _can_ it hear?

- add some time alignment. How much can this help? What about the free-space situation will time alignemnt _not_ help?

- only now, with a good understanding of drivers & crossovers in a reflective-free environment, does it make sense to add : what happens when I add reflections? Will time-alignment or EQ help ... or not? Are there _other_ tools in my handbag that are more effective ... like controlling the directivity of drivers near glass (perhaps the worst reflector).

Science must progress like this, in my experience, or we become lost ... like sailors wandering aimlessly at sea 

The other dimension to consider, of course, is how well each driver behaves for large signals as well as small  I'm not suggesting that driver distortion is the paramount concern, of course, just that it's a "dimension" in the array of issues that should not be ignored.

In short : Separate issues, where applicable. Build a complex case as an array of simpler cases. That's how science works


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## Scott Buwalda (Apr 7, 2006)

I can appreciate that, as a scientist. Lumping problems gets us nowhere. Defining each problem individually, and isolating that one problem, and working on it as the only variable, is naturally the scientific method. 

It *sounds* like we're saying the same thing, but differently: mechanics are important (reference your tweeter waveguide example). It also sounds like we're both dancing around head-related transfer function. I did skim a bit though, since I really do need to leave for the airport shortly. LOL

One thing that did stand out to me is your discussion about crossovers and phase. You said "start with a well-designed crossover for point-source drivers in free space...such a beast will comprehend magnitude as well as phase..." I have a little bit of an exception with that last part. Phase on the model on the computer screen, or phase in a car, in real life?  We all know the ideal system would use no filters at all. All crossover filters, bar none, introduce phase shift and a time delay. A frequency-dependent phase shift *might* be fixed with time domain adjustment, for certain frequencies, but may negatively affect other frequencies. Music, by nature, goes in and out of phase as a matter of course. Multiple drivers producing the same critical vocal band can and will lead to problems, unless they are on a mechnical zero delay plane to the listener. This is exacerbated in a car, as described above. There's definitely no perfect filter, and in many cases, filters are usually barely adequate. I suppose at the end of the day DSP is a powerful tool, since frequency response deviations are reduced considerably as filter order is increased. Said response deviations are then attributed mainly to time misalignment. I suppose on paper, you're right, time domain adjustment can be of great help, but in a car, all bets are off, and that's when I take my white collar off and throw my blue collar on and rely on personal experience. My personal experience says wide-bandwidth drivers work the best to capture the entire vocal spectrum without introduction of another pair of speakers, crossover, time, and phase deviations, group delay with multiple speakers, etc., etc., etc. 

*sigh*

At the end of the day, it's probably best to not try and over-analyze the pallet we're forced to paint on, and just enjoy what sound quality we were able to eek out.

Scott


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## Problemhouston (Apr 2, 2009)

May I be excused from the thread. I need to make an appointment with my neurologist. I read Scott’s and lycan’s posts over and over trying to get a handle on it all and I just don’t have the background. I am in accounting for gods sake....


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## lycan (Dec 20, 2009)

Scott Buwalda said:


> I can appreciate that, as a scientist. Lumping problems gets us nowhere. Defining each problem individually, and isolating that one problem, and working on it as the only variable, is naturally the scientific method.
> 
> It *sounds* like we're saying the same thing, but differently: mechanics are important (reference your tweeter waveguide example). It also sounds like we're both dancing around head-related transfer function. I did skim a bit though, since I really do need to leave for the airport shortly. LOL
> 
> ...


Well, when i mentioned point source drivers _in free space_ ... and a good crossover design ... i was most certainly _not_ talking about them in a car  That's one of my main points. You have two options, it seems :

1. Lump all problems together, and quickly point out how the multitude of variables tends to "ruin everything", or ...

2. Separate issues. Start simple, and build complexity as needed. START with crossover design in a reflective-free environment, for example. Only when this process is understood, can we hope to understand what happens as we add reflective surfaces to the mix. Otherwise, we'll just be randomly tossing out a vocabulary of problems, and wander aimlessly in the dark.

SO ... let's make sure we understand crossover design in an environment that is reflection-free, as a _first step_. Phase response at crossover is a VERY important, quite well understood aspect of crossover design, especially in this "ideal" environment, because it will dramatically impact how response of the two drivers _combine_ at the crossover frequency. So any decent crossover will already comprehend magnitude, phase, group delay, and transient response, because it has to ... otherwise the speaker (even in this ideal environment) will sound like crap. Sure, there's no ideal crossover even in this ideal environment, but arbitrarily large complexity will get you arbitrarily close  The ear responds to relative phase, not absolute phase, and any half-decent crossover ... even in the ideal environment ... must comprehend the relative phase of drivers at crossover, to understand the combined output at crossover.

NOW ... let's imagine what happens in a reflective environment. We are slowly adding complexity, making sure the simpler (more ideal) cases are well understood before complexity is added. It's our goal to approach a model that adequately describes a car, or at least those aspects of the car that are important for the discussion at hand. Crossover theory begins to comprehend reflective environments by adding a new requirement, or constraint ... namely, _power response_. It's an over-simplification, to be sure, but one that begins to hint at the fact that we place speakers in rooms (reflective environments), and consequently it's a real constraint that any modern crossover pays attention to.

It's not my goal to describe crossover theory in detail, but merely to point out that it makes sense to understand "ideal" cases first, and progress to the more complex as needed. We'll _never_ understand how reflections impact speaker crossover, until we understand crossover behavior without reflections first. We must ALWAYS start with the "paper" or "laboratory" approach to crossover design, then add the "real world" complexities until we have an adequate model.

In short, I'm just saying that when somebody mentions ONE of a multitude of variables, like large-signal distortion, it serves no purpose to respond with : "Distortion? Well what about reflections, vibrations, diffractions, absorptions, doppler distortion, side bias, transient response, group delay, slew rate, road noise, power response, etc.?" This response clouds the issue, and can obviously be invoked to argue against _any_ single variable one cares to mention.

Separate, simplify, then add complexity as needed 

And don't ignore the large-signal performance of drivers ... even in a car!


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## SSSnake (Mar 8, 2007)

> May I be excused from the thread. I need to make an appointment with my neurologist. I read Scott’s and lycan’s posts over and over trying to get a handle on it all and I just don’t have the background. I am in accounting for gods sake....


You're excused.

Some of us ARE following along and glad to see these types of posts again (ECA died and DIYMA is suffering from too much popularity). This is definitely more beneficial than the 1000th post about which sub is better.


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## lucas569 (Apr 17, 2007)

SSSnake said:


> You're excused.
> 
> Some of us ARE following along and glad to see these types of posts again (ECA died and DIYMA is suffering from too much popularity). This is definitely more beneficial than the 1000th post about which sub is better.


BUT which sub is better??? 

JK! good read, just wish the it was broken up (cough,scott) more. my old eyes cant handle it!


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## Problemhouston (Apr 2, 2009)

SSSnake said:


> You're excused.
> 
> Some of us ARE following along and glad to see these types of posts again (ECA died and DIYMA is suffering from too much popularity). This is definitely more beneficial than the 1000th post about which sub is better.


I understand and fully agree which is why I keep coming back. I love this stuff.


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## Patrick Bateman (Sep 11, 2006)

Scott Buwalda said:


> The final question is "do you give anything up, design or performance wise, in creating a wide bandwidth tweeter." The answer is usually yes. The race is on by virtually every manufacturer (except HAT and perhaps a few others) to build large diameter, heavy moving mass tweeters to eek every last ounce of bandwidth out of them. The result is an industry currently predisposed to having to cross tweeters over extremely low to both make-up for midrange/midbass shortcomings, and get that ever-important low resonance frequency as a certain calling card. The reality is that as moving mass increases and diameter increases, polar response worsens, the bandwidth shifts downward, and listener fatigue generally increases because of the IMD being carried by the tweeter and its limited suspension compliance. No longer are these large diameter tweeters really good at producing treble, especially to 20,000 cycles. Look at any 28mm or 32mm tweeter at 30- or 60-degrees off axis from 12,000 Hz and up. That’s my point. They’ll work on a board, but may not work so well in a car. That’s also why I’ll never build a huge diaphragm, heavy moving mass tweeter because they frankly usually suck at producing treble and have terrible polar response. The answer to your question, at least as far as Hybrid Audio is concerned, is making two different types of tweeters: a low-resonance tweeter a high-resonance tweeter. There are obvious benefits to both tweeters and can be used at the end-user’s discretion to achieve different goals.
> 
> Scott


According to this post, a "heavy moving mass tweeter... usually suck(s) at producing treble and has terrible polar response."

This is misleading.

All speakers beam, whether they have a diameter of 1", or a diameter of 15". The difference is that the 15" speaker will begin to beam at a frequency which is lower in frequency.

















Peerless 811830 1" tweeter
















Peerless 830970 2" woofer
















Peerless 850490 8" woofer​
To demonstrate this point, here is the polar response of a 1" tweeter, a 2" woofer and and 8" woofer. At 10,000hz the 1" tweeter's off-axis response is reduced by approximately 6dB. At 2000hz the 7" diaphragm of the woofer is down about the same.

This can be calculated easily - it's the speed of sound divided by the piston's diameter.

The illustrations above demonstrate my first point:
*All speakers beam.*

Now that we have that out of the way, let's discuss how we want that curve to look.







Here's a target curve that I stole from Andy at JBL. I think this is an accurate target. Pay particular attention to what's happening from 5khz to 20khz. In those two octaves, _we want the response to fall by about 3dB/octave._

Now that we have our "target curve", which speaker is the closest match?

*I would say that the 30 degree off-axis curve of the 1" tweeter and the 2" midrange is the closest match for our target curve.*

Yet how many people obsessively aim their tweeters? These polar curves demonstrate that _the best curve is often the off-axis curve, not the on-axis._

There's one last "trick" we can use to our benefit. The closer you get to a speaker, the more you want to attenuate the treble. And the further you get from a speaker, the more you want to boost it. The reason that this happens is because reflections dominate the soundfield as you move away from a speaker, and high frequencies are attenuated by reflections to a greater degree than lower frequencies.

This works to our benefit - it means that we'd typically want the passenger side tweeter to play louder for the driver, and vice versa. (Note that the 60 degree off axis curve is about half as loud as the 30 degree curve, when the speaker is beaming.)

In summary:

It's misleading to say large tweeters have "terrible polar response." All pistons beam, big tweeters beam at a lower frequency.
If you are seated equidistant between a set of speakers, listening on-axis has it's advantages. In the car, _the off-axis curve of a loudspeaker often sounds better than the on-axis curve._
Larger pistons have additional advantages besides a better curve. For example, they play lower, and can play louder due to higher displacement.


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## lycan (Dec 20, 2009)

Patrick is correct : Polar response has virtually _nothing_ to do with moving mass. Polar response (off-axis response) is a STRONG function of driver diameter, a WEAK function of driver shape, and a NON function of just about everything else (assuming we're not counting waveguides, or a subset thereof called horns).

It all boils down to understanding why multiple sources, displaced in distance, have constructive & destructive interference patterns as you move to points in space where the distance to each driver is different. Should be readily apparent that if I have two point sources, some distance apart, each playing the same frequency, they will constructively _add_ if my ear is the same distance to each driver. Now if the distance is _different_ to each driver, i may start to get destructive interference (aka subtraction or cancellation) ... depending on wavelengths & distances. This is ALL you need to know, to understand why speakers beam. After all, even a single driver is nothing more than an array of point sources laterally displaced around the surface of the cone  And you can quickly see that cone diameter is, by far, the strongest indicator of when (in frequency) the driver starts to beam.

Just another good example of why it makes sense to break things down, into simple cases, to understand the vast array of variables with which we must contend in car audio 

EDIT : Another point worthy of consideration. The "off-axis" response of drivers can be misleading, in this sense : many car audio enthusiasts might quickly conclude that we should use drivers with GREAT (meaning, less-attenuated) off-axis response, since in a car we tend to listen off-axis. Makes sense, right? Not so fast ... for two reasons (at least) :

1. If you're interested in optimizing the front stage for BOTH front-seat passengers, it sure would be nice to "attenuate" the driver that's closest to EACH listener, to help combat side bias. How the hell can you accomplish that electronically? Short answer : you can't. But you can APPROXIMATE that _mechanically_, by aiming drivers so as to intentionally EXPLOIT the attenuated off-axis response of the drivers. If you sit on the left side of the vehicle, the _left_ driver output is attenuated ... this = good. If you sit on the right side, the _right_ driver output is attenuated ... this = good. Of course, un-aided off-axis response is a crude approximation ... the use of a waveguide is a big improvement, in my view, because waveguides tend to make the off-axis response less frequency dependent (without waveguides, the off-axis response is very frequency dependent, as the driver's natural tendency to beam comes into play). In other words, one can look at a waveguide as a wonderful device that creates an off-axis response that resembles a frequency-independent attenuation of the on-axis response. Should be wonderful for helping to combat side-bias 

2. Reflections! GREAT (meaning, less-attenuated) off-axis response also creates GREAT (meaning, less-attenuated) reflections. Not necessarily your best friend when trying to recreate accurate tonality & staging in a vehicle.

So be careful looking for that driver whose off-axis response is "just awesome" ...


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## Dryseals (Sep 7, 2008)

lycan said:


> Patrick is correct : Polar response has virtually _nothing_ to do with moving mass. Polar response (off-axis response) is a STRONG function of driver diameter, a WEAK function of driver shape, and a NON function of just about everything else (assuming we're not counting waveguides, or a subset thereof called horns).
> 
> It all boils down to understanding why multiple sources, displaced in distance, have constructive & destructive interference patterns as you move to points in space where the distance to each driver is different. Should be readily apparent that if I have two point sources, some distance apart, each playing the same frequency, they will constructively _add_ if my ear is the same distance to each driver. Now if the distance is _different_ to each driver, i may start to get destructive interference (aka subtraction or cancellation) ... depending on wavelengths & distances. This is ALL you need to know, to understand why speakers beam. After all, even a single driver is nothing more than an array of point sources laterally displaced around the surface of the cone  And you can quickly see that cone diameter is, by far, the strongest indicator of when (in frequency) the driver starts to beam.
> 
> ...


But what stage are you trying to build for? I think too much emphisis is being built on a frontal stage. When I say that, I mean too many folks are trying to focus on moving the stage forward by placing the speakers in a foward mount position that tends to aim the speaker at the persons ear. TA needed for correction.

But what if we move more towards using the cabin in a way that projects the stage forward. I'm talking reflections here. Can my ear really tell the difference in TA from two or three sources arriving at the approximate same time. I think if they are close enough together we can't. 

Knowing the cabin size can tell us a lot about where the focus should be, at what length in the cabin will the highest frequency be available to our ears before the reflections from that same sound are there also. Take a 120hz signal, one full wave will take 112.5 inches to complete one cycle. So say and average cabin distance of 48 inches, the forward portion of the signal has passed your ear and is beginning to return back to you as the bottom end hits your ear. If we say 48 is the distance from speaker to head, then it will take a signal higher than 281Hz to be able to complete a full roll before the reflections are coming back at you.

Just like a tweeter in the home speaker will sound brighter with a wood floor than a carpeted floor. Doesn't tend to destroy the sound, may deaden it a tad but creates enough reflections to make the same tweeter seem brighter.

So what if I build at a more off axis point allowing reflections to be my friend.

This is my goal for my little 350Z. It's cramped for space, then I build using the space available. Nothing pointed directly at me, everything relies on off axis placement, physically separated in distance up and down by crossover points and let reflections fill the forward cabin. And knowing the distance fom the rear to the front, I can set my crossover points to allow nothing but the lower freqs to come from the rear, by distance/speed of sound. 

This way if I turn my head, the sound is still the same, no one point can be determinded. It just appears as if it is more forward.


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## Hernan (Jul 9, 2006)

Dryseals said:


> But what stage are you trying to build for?...


You are talking about late reflexions. In a car the enemy are ealy reflecions. Reflexions from the windshield, dash, pillars, doors. 
Some of them are nealy as strong as the direct sound and the produce comb filtering at various points of the FR.


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## Hernan (Jul 9, 2006)

Very interesting discussion going on.

Back to the topic, why some people like speakers that have above average distorsion?

In my very own personal view, a bit of harmonic distortion sometimes soften, blurs the sound at low to moderate levels. 

A superlow distortion system sounds dry in comparation.

As volume increase, distortion becomes anoying and cause early ear fatigue.

The "Scott" filosophy, wide bandwidch drivers, is an example where the usual trade off in car audio is evident. The drivers are not superlow distortion but they solve the problem of a pair of drivers at bad locations with a bad implemented crossover.

Just my 2c.


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## DanMan (Jul 18, 2008)

Scott talks about having one driver reproduce the vocal range. I understand that this would help with a center image-well, a vocal image anyway. How does this affect image location of other instruments? What gives us an accurate stage representation in an instrumental?

Anybody?


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## Dryseals (Sep 7, 2008)

Hernan said:


> You are talking about late reflexions. In a car the enemy are ealy reflecions. Reflexions from the windshield, dash, pillars, doors.
> Some of them are nealy as strong as the direct sound and the produce comb filtering at various points of the FR.


I understand comb filtering very well, the direction of the speaker can help reduce early reflections. In a car it's a compromise, In a small car like mine it's a real compromise. My wifes Tahoe is an easy build compared to the car, so is my truck. I've been driving this little thing around now for over a year, there's not much room to work with. So placement is going to be key. No matter which way you face a speaker in it, anything pointing towards the driver/passenger is easy to pin point. Pin pointing the source is what I'm trying to avoid. 

The worst car I ever had for sound was an 85 Corevette, that thing is a glass oven. Took some work but best overall sound came from keeping the speakers pointing in a manner away from the driver, off axis. But the dash was very large and using the large windshield as a reflective source proved to move the sound stage in front of you. This car has a ver small dash pad, nothing will fit without obstructing the view.


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## MarkZ (Dec 5, 2005)

lycan said:


> Case in point : a tweeter up high, and midrange down low ... separated by more than 1/4 wavelength at crossover. Let's say the drivers are time aligned (trivial these days) ... so the wavefronts launched by the drivers arrive at the ear at the same time, and the acoustic combination, through the crossover, occurs at the ear just as if the drivers were coincident. How can the ear possibly tell that the midrange is below the tweeter? It's easy to prove, easy to demonstrate, and it's quite well documented, that we don't recognize height cues until the treble. So the ear simply has NO WAY to determine that the midrange is mounted low, well _below_ the tweeter (it's a completely different story, of course, if the midrange is _laterally_ displaced from the tweeter). And no, you won't often find such discussions in the home audio realm ... simply because the home environment has not forced the enthusiast to understand localization as well as the more hostile car environment.


Depends. Are we assuming that the driver's head is bolted to the car? 



> My view is this : don't worry so much about crossovers in critical bands (and surely, the human voice is a critical band of extreme interest). Instead, worry more about placing drivers in a manner consistent with how the ear _localizes_ sound
> 
> Finally, should we worry about a couple percent distortion from drivers, when there really is more to worry about in a car? This argument is perched on quite a slippery slope ... why worry about distortion from amplifiers? Why worry about noise floor in your signal processing chain, when the noise floor in a car is so damn high? Why worry about frequency response, or transient response, in such a miserable, god-forsaken environment? There's two answers, i think : first, some of the nastiness in a car is, to put it loosely, _uncorrelated_ with the music we're playing ... and, much of what _is_ correlated, finds that correlation in widely _separate_ frequency bands (obnoxious sub-bass vs. delicate midrange, for example) ... and the ear is surprisingly good at distinguishing (and often, ignoring) uncorrelated junk from closely-correlated junk. And second, any true car audio enthusiast will endeavor to improve each & every aspect of the reproduction (certainly attacking the low-hanging fruit first) until a level of satisfaction is achieved. Ultimately, then, a few percent of distortion from _any_ element, if it's above the audibility threshold, must be open to scrutiny.


I'm not sure I understand what you're saying here. How is the car's nastiness uncorrelated? Are you just talking about road noise?

I think some of the biggest issues we face in the car have to do with nearfield listening problems, reflections, and occlusion. So I'm not really sure how your "not correlated" argument is being applied here.


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## lycan (Dec 20, 2009)

MarkZ said:


> Depends. Are we assuming that the driver's head is bolted to the car?
> 
> 
> 
> ...


Road noise uncorrelated, yes. But also, for example, "irregularities" in the subbass (poor transient response from a mis-sized enclosure-in-vehicle, maybe) may not impact our enjoyment in the midrange. That's kinda what i meant by widely differing frequency ranges. Also, for example, some comb nulls above 8kHz not really impacting vocal reproduction in the midrange (and lower treble). The real point being : don't just lump all audio difficulties in a car into one basket, and use that basket to argue against the need for a low-distortion midrange driver


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## Patrick Bateman (Sep 11, 2006)

Dryseals said:


> But what stage are you trying to build for? I think too much emphisis is being built on a frontal stage. When I say that, I mean too many folks are trying to focus on moving the stage forward by placing the speakers in a foward mount position that tends to aim the speaker at the persons ear. TA needed for correction.
> 
> But what if we move more towards using the cabin in a way that projects the stage forward. I'm talking reflections here. Can my ear really tell the difference in TA from two or three sources arriving at the approximate same time. I think if they are close enough together we can't.


Can we tell the difference between two or three sources arriving at approximately the same time? Let's think about this for a moment.

Let's say you have two woofers on each side of the car, and they're playing 100hz. The woofers in each pair are ten inches apart. 100hz is one hundred and thirty five inches long. So will the spacing be audible? I'd guess that each pair would sound like a single woofer, located equidistant between the two. (IE, the sound will "merge" for the most part, because the wavelength is so long.)

If they're playing 1000hz, things get trickier. That's just 13.5" long, and the two are going to suffer from lots of comb filtering due to the much shorter wavelength.

Even worse, the frequency response is going to vary depending on angle.

In a nutshell, the degree to which you can seperate drivers is highly dependent on the frequency. It's a heck of a lot easier to do it at 100hz than 1000hz.


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## masswork (Feb 23, 2009)

Very nice discussion indeed!

Andy, Patrick... quick question:
Where do you get those Harman's document? Is it available for download?
I think its very worth to read.

Thanks


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## diegoejea (May 11, 2009)

Dear all,

I will give a brief comment, because this discussion is quite deep, and the best way to ride this kind of discussions is face to face. Over a forum, it can become to a huge mess.

First of all, sorry for my english, I wouldn´t like to create missunderstandings.

I talk as telecomunications engineer, especialiced and enthusiast of audio.

What you are discussing about is very interesting. But you are giving too much importance to some points that are not. 

Forget a car is such a difficult environment. It is diffiicult yes, about speaker solid fixing, and aiming. But not such a difficult about acoustic environment. Forget it. Why? Just ear a person talking at your side in a car, or play a real violin in the passengers seat, in your car. Does it sound real for everybody in the car? Yes, it sounds!! It is real!. However, this same sound, played throught your Hi End speakers, doesn´t sound as real.

Why? 

- It is not because the violin plays from one single point, and the speakers are a bit separated --> The violin just next to you, is radiating sound along its entire surface, and are separated points from your point of earing, even more than 30 degrees, along its surface.

- It is not because the slight distortion of the cone material and the non distorting real violin --> There are a lot of violins made of different materials, diferent cases makes diferent resonances, what could mean distortion in comparison to an Stradivarious?? No, all the different sounding violins, sound real for us playing live in our car... Besides, a Stradivarious is not the original violin, is not the model. All the violins are violins, more or less loved... But they distort their generated sound a bit differently... like the different cone materials which have slight different amounts of distortion... (I mean slight differences in distortion because 2 drivers. Of course distortion has to be the less)

- It is not because your speakers need some time alignment to sound as real



But the violin, or whichever instrument, or real sound played in your car, sounds live real! No doubt! . However, this played throught the speakers doesn´t sound as real, all of us know this. You can´t lie the ear, close your eyes, and you can distiguish a real violin in your car from the sound played from your speakers.


The reason of this, in my opinion, is because quite different causes that you are arguing in this discussion. The causes you debate are real, but not the key. They don´t solve (and won´t do) the problem of getting the real sound from a speaker set.

The main mistake, is assuming and applying basic signal theory, in this manner, to look for the solution. This makes you to give too much interest on these points, not essentials in my opinion. In my opinion, you are not applying properly signal theory (not you, but almost all the audiophile people along the world). 

You are wrong applying signal theory along the years in audiophlie forums. 

I agree you use perfectly the theory and maths to talk about phase distortion, group delay, to analize graphs, to understand spectrum, domain, etc...

But you are ignoring you are applying Fourier theories and systems theory, what are intended for stationary signals. Only for stationary signals! What means it is a mathemathical assumption to understand the real world, but what never happens:

*stationary signals are signals without beginning or end*

Real signals, real world, is transient meanly. And all fourier theory used by audiophiles to try to look for solutions, is not worth.

The theory for transient world, is more complex. 

The music, the sound, the variations of the air pressure caused by the real world interactions, *is transient*

This is what we don´t find in speakers, they are not good at transients performance. The more the speaker´s technology is better at transients, the more they souns real to us (i.e. planar tweeters, electrostatic ones, plasma...)

Of course, all these things you are discussing are important, but never will drive you to get the real sound. Your discussion subjects are based on simple signal theory, which only works for stationary signals. And this is the big mistake always done by audiophile world, to put a lot of interest in this stationary theory, thinking it will drive to the finding of the real sound.

I won´t get into all these things I consider are the key. But I will only say that Scott Buwalda is taking this in consideration when he says a speaker should be always wide band, even if it is only for midbass. The cleaner and faster is the high end of a driver, the cleaner will be everything down to it. More as we go down. Transients is the key for reality.

Of course, you can have a great transient performer speaker, but bad controlled around its Fs for example, or with peaks, or with high cone blending distortion, what would be a bad sounding one. But what I am trying to say is, the most important thing to get real sound, is transient performance. Of course, the rest as to be kept as well as it is being kept by manufacturers.


Nowadays, 6.5" regular drivers are very bad at midrange transient capabilities. It doesn´t matter if you cut your tweeter above the vocal range to get pristine vocal reproduction. You will have a coherent sound, but never pristine. A 6.5" driver never vibrates, never plays, as lightly and fast as a 3" or 4" good driver. So, althought you let all the vocal range to the midwoofer, you won´t get pristine real sound. A 6.5" driver don´t play real sound at midrange. It can be smooth, sweet, lovely and amazing, but never real, because it is not fast, it has not the best transient response.


So, I think the key is to look for better transient response drivers, to get that important, loved and needed midrange, in order to get real midrange reproduction (what is extensible to all frequency range, according to the driver capabilities) 

Is there such a good 6.5" car audio driver? I don´t think so. I have owned some of the best HiEnd midbass drivers, and they sound amazing and lovely, but they sucks at midrange clarity. Some of them are better, some of the are worse... But they exixt for example in Pro sound. As you know, a 12" paper driver can play very clear and fast midrange. Unfortunately, they usually are paper made, and haven´t the low distortion levels what have the more rigid cone material drivers.

In car audio, I am afraid you would need an incredible huge BL factor and enoumeos feeding to get a woofer so clear and fast as the bests 3" midranges, and hits as low as the current car audio Hi End drivers ... This dimensions are impracticable for car audio... It is very difficult to engine, and easier to get with paper cones for example. But I think this is the way.


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## MarkZ (Dec 5, 2005)

Interesting post. But I must disagree with your insistence that stationary signals don't exist (which is basically what you're implying...). To a VERY good approximation, and with a good spectral estimation technique, the signals are "stationary enough". I think you're throwing the baby out with the bathwater when you dismiss everything fourier-based just because you're not content that they satisfy stationarity. Maybe I don't understand your point. 

Besides, as lycan has already pointed out, transient response cannot be so easily separated from the frequency response of the driver. If a driver can reproduce high frequencies, then it stands to reason that it will be "fast" enough and will decay appropriately (assuming proper bandwidth is used).

The car, however, may not.

Also, there are several 6" drivers that have good transient response. The B&C 6mdn44 which I use is a good example (although admittedly it's a MIDRANGE driver, not a WOOFER). The main problem with these drivers, as others have said, has to do with their polar response -- but whether or not it's even a problem depends on the particular installation. But I do agree that typical 6.5" woofers, especially the one badged as "car audio", often suck at midrange.


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## lycan (Dec 20, 2009)

diegoejea said:


> Dear all,
> 
> I will give a brief comment, because this discussion is quite deep, and the best way to ride this kind of discussions is face to face. Over a forum, it can become to a huge mess.
> 
> ...


With all respect ...

Your comments about Fourier Theory are wrong. Fourier Theory is applicable to ALL signals, steady-state or transient.

We typically use Fourier Series for steady-state, periodic signals. Example : periodic sinewave, or periodic square wave.
We typically use the Fourier Transform for transient signals. Example : one period of a sinewave, or one period of a square wave.

But it is flat wrong to suggest that Fourier Analysis is not applicable to music. Music is nothing more than a signal ... in electrical, mechanical, or acoustic form. And it is therefore subject to all signal processing rules & laws.

Also, we OFTEN test drivers with transient signals to test their transient performance : examples incluse cumulative spectral decay, and tone bursts. Large signal distortion is typically a sinusoidal steady-state measurment, I grant you, but that doesn't mean we only test drivers with steady-state signals.

Furthermore, it's incorrect to suggest that, since a musical instrument "distorts" a signal ... creating harmonics of a pure fundamental, for example ... then it's OK for a driver to do the same. The loudpspeaker has a fundamental difference from the musical instrument : the speaker is part of the reproduction chain, the musical instrument is not. Therefore, the speaker is subject to all the rules of acoustics & signal processing that determine _accuracy_.

I'm not suggesting that large signal distortion of a driver is the most important parameter. What I am saying is this :

1. Large-signal distortion from a driver may, in some cases, sound quite pleasant. But it's not accurate.

2. There are a _host_ of problems to contend with in car audio. The entire _group_ of problems, though, should not be used to argue any _single_ problem into insignificance.


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## diegoejea (May 11, 2009)

No no Mark!! I don´t dismiss Fourier theory! I love it!
What I dismiss is the Fourier theory (not only fourier, but signals and systems) usually used by audiophlies. They base their findings on it. And it doesn´t work.

Of course you can approximate reality by stationary signals, but not transients. And what I mean is, if you miss transients, you miss reality.

Just an example which for sure all of you know. Just ear a subwoofer playing vocals. They can play them loud in the low vocal range. I mean, they can play 200 Hz frequs very loud. But the sound is a ****. Why? because although the big subwoofer can get the needed excursion to get SPL at 200 Hz in stationary instants, they can´t accelerate enough fast to play the transients as the electric signal orders.

You can assume sometimes reality is stationary, but if you ignore transients, you ignore reality. Reality, fundamental and harmonic components, are full of transients.

Assume signal theory as stationary, was the first step to get out the mathematical demosntrations, as occurs with mechanical, and physics in general. But if we hold only this point, we won´t step forward towards reality.

So this is what happens to all the drivers. A midwoofer will be never good or real at vocals because they can´t play clear at the high end, whereever up you cut them. 

It happens the same to tweeters.


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## diegoejea (May 11, 2009)

Hi Lycan,

I agree with you, if a woofer ca play highs, it is good at transient response for lower frequencies, of course. And it can be detailed analized.

But, do you know a 6.5" cone driver which plays highs as fast as a B&G Neo3?? (Please, differenciate fast, clear, of loud) Why not? Because they can´t. Could you make one like that? Yes, but you know what you would need...


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## Patrick Bateman (Sep 11, 2006)

diegoejea said:


> The main mistake, is assuming and applying basic signal theory, in this manner, to look for the solution. This makes you to give too much interest on these points, not essentials in my opinion. In my opinion, you are not applying properly signal theory (not you, but almost all the audiophile people along the world).
> 
> You are wrong applying signal theory along the years in audiophlie forums.
> 
> ...


There isn't anything magical about Buwalda's speakers. The ideal speaker is a point source that covers the entire bandwidth. If we were listening outside, and on-axis, directivity would not be a concern.

Since we're listening to speakers in a car, we want directivity, and good off-axis response. (Because *we're* off axis.) Ideally we'd have a point source too.

This isn't rocket science really.

No offense, but I think the things you are attributing to good transient response are actually due to something else entirely. When you take a sound and break it up between two speakers, each speaker is going to have a unique power response. In addition, the two drivers will constructively and destructively interfere with each other.

So these things that you attribute to good transient behavior, in my opinion, are actually due to the fact that Buwalda's speakers approximate a point source.

There are other ways to do this also. The JBL 660GTI uses a waveguide to make the tweeter "appear" to be the same size as the woofer. Buwalda does it with one driver. I do it with a Unity horn. Each has it's disadvantages. The JBL will have the worst vertical directivity. Buwalda's might have the highest distortion, depending on where it's crossed over. Higher is better, and he's acknowledged this. My solution is the ugliest, but combines the low distortion of the JBL with the good directivity of Buwalda's solution.

All three of us are converging on the same goal from different roads : a point source.


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## lycan (Dec 20, 2009)

diegoejea said:


> No no Mark!! I don´t dismiss Fourier theory! I love it!
> What I dismiss is the Fourier theory (not only fourier, but signals and systems) usually used by audiophlies. They base their findings on it. And it doesn´t work.
> 
> Of course you can approximate reality by stationary signals, but not transients. And what I mean is, if you miss transients, you miss reality.
> ...


Nobody is ignoring transients. CSD & tone burst tests are used routinely for testing drivers (and Fourier Theory is also routinely applied to these tests ... just look at the horizontal axis in a CSD test ) It's just not what this thread is about  Nor is this thread about the best size enclosure for a subwoofer, to optimize it's transient response 

This thread is about large signal distortion from drivers. Admittedly, this test is a large-signal, steady-state test ... and NOT a transient test.

But nobody is ignoring transient response from drivers, it's just not the subject of this thread.


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## dbiegel (Oct 15, 2006)

Try listening to a pair of drivers with excellent transient response in a home theatre, and then listen to the same pair installed in your car. Then tell me that speaker transient response is still the core of our problem.


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## lycan (Dec 20, 2009)

diegoejea said:


> Hi Lycan,
> 
> I agree with you, if a woofer ca play highs, it is good at transient response for lower frequencies, of course. And it can be detailed analized.
> 
> But, do you know a 6.5" cone driver which plays highs as fast as a B&G Neo3?? (Please, differenciate fast, clear, of loud) Why not? Because they can´t. Could you make one like that? Yes, but you know what you would need...


I'll tell you EXACTLY why not, and i'll even hint at Fourier Theory to explain it 

A so-called "fast" driver means that it can accurately reproduce high frequency signals ... nothing more. Fourier Theory tells us that signals of SHORT duration have lots of HIGH FREQUENCY content.

So, when you're wondering why a 6.5" driver isn't "fast", that same question can be asked in the frequency domain (thank you, Fourier) : why doesn't a 6.5" driver have good extension into higher frequencies? There are typically several answers :

1. Coil inductance limits high-frequency performance. It contributes to a first-order low-pass filter.

2. Cone material may not lend itself to high frequency extension. Resonances, for example.

3. Off-axis performance will suffer dramatically as frequency increases, due to nothing more than the diameter of the driver cone. Consequently, the _power response_ of the larger driver will suffer as frequency increases.

There are other reasons, but these are the big ones. And please note, the answer has nothing to do with any failings of Fourier Analysis.


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## diegoejea (May 11, 2009)

Patrick Bateman said:


> There isn't anything magical about Buwalda's speakers. The ideal speaker is a point source that covers the entire bandwidth. If we were listening outside, and on-axis, directivity would not be a concern.
> 
> Since we're listening to speakers in a car, we want directivity, and good off-axis response. (Because *we're* off axis.) Ideally we'd have a point source too.
> 
> ...


Dear Patrick,

I agree 2 separate speakers beaming at you, will make different interferences at your ear, creating dips or peaks, of course. It is explained by stationary Signal Theory, and I think you use it properly. 

But what I say, is you are giving too much importance to these things, and are not the way to reality. It doen´t matter all these things if a violin is played in the back seat of your car, you ear it as real. But it is because transient full activity in the real signal.



lycan said:


> Nobody is ignoring transients. CSD & tone burst tests are used routinely for testing drivers (and Fourier Theory is also routinely applied to these tests ... just look at the horizontal axis in a CSD test ) It's just not what this thread is about Nor is this thread about the best size enclosure for a subwoofer, to optimize it's transient response
> 
> This thread is about large signal distortion from drivers. Admittedly, this test is a large-signal, steady-state test ... and NOT a transient test.
> 
> But nobody is ignoring transient response from drivers, it's just not the subject of this thread.


Dear Lycan,

I know you think of and measure transient response. But the CSD is not a transient test (I know, you will think who I am to say this...). CSD is only a test to know the decay behavior of a driver.


As we say, this is a deep subject, and according to Lycan, for another thread! I agree, and I will finish right now.

But let me tell you that I am completely opposite to the theory applied by audiophlies to look for the real transduction. 

I hope I don´t sound rude. Sorry for my english, It is a pleasure to talk with you.

Best regards from Spain,

Diego


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## diegoejea (May 11, 2009)

Some answers in the quote!



lycan said:


> I'll tell you EXACTLY why not, and i'll even hint at Fourier Theory to explain it
> 
> A so-called "fast" driver means that it can accurately reproduce high frequency signals ... nothing more. Fourier Theory tells us that signals of SHORT duration have lots of HIGH FREQUENCY content.
> 
> ...


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## lycan (Dec 20, 2009)

wrong again, my friend.

- Short duration means MULTIPLICATION in the TIME domain by a step, or gate, signal. This means CONVOLUTION in the FREQUENCY domain. Only through convolution in the frequency domain, can you generate "new" high frequency content. Nevertheless, i stand by my description : "fast" signals have high frequency content. And an accurate reproduction of that high-frequency content requires a system, filter or driver that can play well into the high-frequency realm. Again, there's nothing about "transient" signals ... fast, or slow ... that escapes Fourier scrutiny.

- a first order low-pass will necessarily reduce high frequency content in the signal it passes. Look at what happens to a simple step function, when passed through a first-order low-pass filter : the rising edge is SLOWED-down. It's not just the phase response causing that, it's the magnitude response as well. Furthermore, it's not like the low pass filter changes "character" for transient signals; no matter what signal you put through a low-pass filter, the filter will reduce the high-frequency content ... and therefore prevent the output from changing "fast", no matter if it's a periodic steady-state signal, or a transient signal.

- A subwoofer that can play at 200Hz, that sounds "blurred" at 200Hz? I have no idea what you're referring to. Unless, you're referring to what a subwoofer sounds like when properly crossed over, and all other drivers in the system are turned off. But if that's what you mean, then you _really_ don't understand what a low-pass filter is supposed to do. Or, perhaps you're referring to the transient response of the high-pass filter formed by the driver-plus-enclosure? If that's the case, that's fine ... but the complete description of the driver-plus-enclosure high-pass filter is certainly NOT outside the realm of Fourier analysis!

- cone resonances limit how high a driver can play. You're stuck on this "transient" misunderstanding, as if it's the only thing that determines a driver's "sound" or effective frequency range, and what i'm telling you is that there are several reasons why a 6.5" driver can't play effectively into the treble.

- in many cases (especially including inside a small, reflective environment) the _power response_ is a better description of what we actually hear. And I'm stating that power response of a large diameter driver prevents it from being an effective tweeter. Not the only reason, of course, just one of many. And it has nothing to do with "transient response".

Seriously dude, you're just tossing around jargon you don't understand


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## SSSnake (Mar 8, 2007)

I hate to come into this thread and sound like a douche bag again but.. diegoejea where did you get your engineering degree? Your ideas about fourrier tranforms, frequency response, and transient response are VERY misuided. Most of your suppositions would be dismissed by second year engineering students.


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## lycan (Dec 20, 2009)

SSSnake said:


> I hate to come into this thread and sound like a douche bag again but.. diegoejea where did you get your engineering degree? Your ideas about fourrier tranforms, frequency response, and transient response are VERY misuided. Most of your suppositions would be dismissed by second year engineering students.


Agreed.

But I would not want to dismiss a basic point that's trying to be made (i think), which is that transient performance of loudspeakers is important too ... and in certain circumstances, "more important" than large-signal, steady-state harmonic distortion (although it may be hard to compare the two on a similar scale of importance). The transient performance may include the high-pass transient response of subs-in-boxes, and it may include energy storage of midrange drivers. In any case, we can certainly use Fourier Analysis to describe transient response as well as steady-state response ... music is not somehow "unique" in the world of signal processing because of its transient nature, and certainly "transient" signals are not some "special class" of signals that are beyond the scrutiny of Fourier Analysis.

But that does not suggest, in my view, that we can dismiss or ignore large signal distortion of drivers ... simply because there's lots of other stuff to worry about. Well, enough from me.


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## diegoejea (May 11, 2009)

lycan said:


> wrong again, my friend.
> 
> - Short duration means MULTIPLICATION in the TIME domain by a step, or gate, signal. This means CONVOLUTION in the FREQUENCY domain. Only through convolution in the frequency domain, can you generate "new" high frequency content. Nevertheless, i stand by my description : "fast" signals have high frequency content. And an accurate reproduction of that high-frequency content requires a system, filter or driver that can play well into the high-frequency realm. Again, there's nothing about "transient" signals ... fast, or slow ... that escapes Fourier scrutiny.


Yes, sorry, you are right, I wrote fast sorry, it is just a product in time domain, and convolution in frequency.

I keep my thoughts, I think you don´t understand transient meaning (sorry for this). I keep thinking you are so used to base your thoughts in stationary theory that you can´t scape from that. Let me explain:

Imagin what we are talking about: 

a sine multiplied by a gate signal in time. 










You know what the spectrum would it be, really? 
An imposible spectrum...

Why the spectrum of this signal is tending to infinite? why is it imposible? Because this signal can´t happen in real life, only can happen in signal exams. Imagine a loudspeaker. It can´t ever start its movement with such an acceleration to follow this sine from 0 and do it perfectly.

Depending on the frequency of this sine, and the system playing it (loudspeaker in this case), the speaker will be able to do the start (TRANSIENT) more or less accurate, but never perfect. It always start exponencially. 

This is not explained by stationary theory, and you are never taking it in account. Stationary theory, as all of us learn at the beggining of our degrees, is limited. There is a pont since where you have to apply transient maths.


Let say, this is a 200 Hz sine. Played by a subwoofer. The subwoofer can play this 200 Hz, yes! And, regarless the inductance of the coil, the sub can get tha maximum amplitude of this 100 or 200 Hz signal, yes! But NOT AT THE BEGINNING. The sub will need some cycles to reach the max amplitude. It hasn´t the enough force, so acceleration. It will need to use the inertia at the o crosses. You know, a space ship will be never able to do a 90º turn without decreasing its speed...

In your stationary theory, looking at the amplitude plot, you will say: Yes, this sub can play 100 Hz tones with max amplitude. But thats the reason you can´t see why it is not accurate. 

The sub example is an easy example, which can be extrapolated to all kind of drivers, and systems...

I don´t want to argue more, because I don´t want to convince you. Only wanted to expose my thoughts.

Best Regards,

Diego


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## MarkZ (Dec 5, 2005)

diegoejea said:


> Yes, sorry, you are right, I wrote fast sorry, it is just a product in time domain, and convolution in frequency.
> 
> I keep my thoughts, I think you don´t understand transient meaning (sorry for this). I keep thinking you are so used to base your thoughts in stationary theory that you can´t scape from that. Let me explain:
> 
> ...


Why exponentially?

It should start based on what you'd predict by lowpass filtering it, which is easy enough to predict by convolving it with a gaussian kernel, for example. As you acknowledged earlier, the voice coil's inductance behaves as a lowpass filter. The abrupt start to that waveform is very high in frequency -- it will be "rounded" by the speaker.

[I'm ignoring effects of cone breakup, etc, but these can be modeled too and applied in the fourier domain...]

How is this contrary to fourier analysis?



> This is not explained by stationary theory, and you are never taking it in account. Stationary theory, as all of us learn at the beggining of our degrees, is limited. There is a pont since where you have to apply transient maths.
> 
> 
> Let say, this is a 200 Hz sine. Played by a subwoofer. The subwoofer can play this 200 Hz, yes! And, regarless the inductance of the coil, the sub can get tha maximum amplitude of this 100 or 200 Hz signal, yes! But NOT AT THE BEGINNING. The sub will need some cycles to reach the max amplitude. It hasn´t the enough force, so acceleration. It will need to use the inertia at the o crosses. You know, a space ship will be never able to do a 90º turn without decreasing its speed...


I think you underestimate the high frequency capabilities of most subwoofers. It won't take a few cycles to catch up -- it will take a small fraction of one cycle. It's just going to have trouble with the abrupt "on".



> In your stationary theory, looking at the amplitude plot, you will say: Yes, this sub can play 100 Hz tones with max amplitude. But thats the reason you can´t see why it is not accurate.
> 
> The sub example is an easy example, which can be extrapolated to all kind of drivers, and systems...
> 
> ...


Thanks Diego.


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## Dryseals (Sep 7, 2008)

diegoejea said:


> Yes, sorry, you are right, I wrote fast sorry, it is just a product in time domain, and convolution in frequency.
> 
> I keep my thoughts, I think you don´t understand transient meaning (sorry for this). I keep thinking you are so used to base your thoughts in stationary theory that you can´t scape from that. Let me explain:
> 
> ...


I"m not so sure I gree with you here. I would think that the first passage of the sine wave would be the most accurate and create the most amplitude. And then fall of. The motor structure, mechanical factors and electrical properties will be best at the first sine wave. The second runs into energy problems stored in the driver from the first wave and so will the following sine waves.
The stored energy may not always be productive, infact I would think that most of the stored energy would be counter productive.
Now if I was making a coil for a sparking system like those in a car, the stored energy is productive, but not for a speaker.
Just my two cents, I'm sure I'll get some change.


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## SSSnake (Mar 8, 2007)

diegoejea,

You made the following statement:



> I keep thinking you are so used to base your thoughts in stationary theory that you can´t scape from that


What equations govern this non "stationary" signal analysis. My thoughts are these non "stationary" signals can be completely defined by a Fourrier tranform. Other than frequency and phase response what in your mind is needed to predict transient response?

FWIW - I do believe transient repsonse is very important. I typically find audio systems have more impact with larger drivers playing higher into the freq range. IMO - This is because of the increased displacement capabilities of the larger driver.


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## lycan (Dec 20, 2009)

a LITTLE bit of signal processing knowledge is a VERY dangerous thing ...

Let's stick with your tone burst example. The Fourier Transform of this signal definitely EXISTS. Yes, it has frequency content that extends to infinity. So what? It's hardly an "impossible spectrum" ... the signal has finite power, and finite energy, so the Fourier Transform definitely EXISTS. It certainly would be impossible to accurately reproduce the signal by a bandlimited system, due to it's frequency content that extends to inifinity ... but again, exactly where is the "failing" of Fourier Analysis?

*FOURIER ANALYSIS APPLIES EQUALLY WELL TO TRANSIENT SIGNALS*

Here's how : apply your tone burst to a low-pass filter (or band-pass, if you prefer, to model a midrange crossover, or a subwoofer-in-box). I PROMISE you that the output signal can be found by :

1. Take the Fourier Transform of the tone burst
2. Multiply the Fourier Transform of the tone burst by the transfer function of the low-pass filter (or band-pass).
3. Take the Inverse Fourier Transform of the result

What you will have is exactly, identically, without question the time domain description of the signal that emerges from your filter (low-pass, or band-pass), when that filter is excited by your tone burst.

If you prefer, you can convolve the tone burst with the impulse response of the filter (low-pass, or band-pass) in the time domain. But the result will be identical to the one obtained by Fourier Transform analysis (multiplication in the frequency domain is easier than convolution in the time domain).

Unless, of course, you think music somehow defies the laws of convolution as well, because of it's "super special" transient nature ... 

Music is not somehow "special" in the class of signals. Neither are transient signals, as I have outlined with the example that you provided ... Fourier Analysis can handle them just fine!

By the way, tone bursts are used to test speakers _all the time_. Linkwitz prefers them to CSD tests, but both tests are in the category of transient tests of loudspeakers. Transient testing is just not what this thread happens to be about ...

A little signal processing knowledge is a very dangerous thing. Jargon can be tossed around to convince anyone of anything ...


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## lucas569 (Apr 17, 2007)

i live for these type of posts!


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## lycan (Dec 20, 2009)

OK, it seems i _never_ learn to stay out these nonsense debates, but i just can't resist the most simple argument imaginable.

I'm sure we've all heard of the importance of "impulse response". The _impulse response_ of any linear, time invariant system is vitally fundamental ... it forms the very essence of convolution, which allows us to describe input/output relationships in the time domain, for _any_ class of input signal.

When we take the Fourier Transform of the impulse response we find something equally fundamental, equally important : namely, the "transfer function" of the system. This tool allows us to use multiplicative techniques in the frequency domain, instead of (more complicated) convolution techniques in the time domain.

Now here's my question : there simply is no more "transient" signal in the time domain than an impulse. The impulse signal is as transient as you can get!! It's so short in time, that the duration approaches zero (in the limiting definition)!

*If Fourier Analysis somehow "collapses" for transient signals ... if Fourier Transforms somehow "don't work" for these 'super-special' transient signals ... how is that impulse responses of systems, and their corresponding Fourier Transforms we call transfer functions, are so vitally important and fundamental in the analysis and synthesis of linear, time invariant systems?*

The answer, of course, should be obvious to anyone with a basic understanding of signal processing : Fourier Analysis applies to tone bursts. Fourier Analysis applies to impulses. Fourier Analysis applies to music


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## thehatedguy (May 4, 2007)

Yeah, well, tubes sound better than sand 



lycan said:


> OK, it seems i _never_ learn to stay out these nonsense debates, but i just can't resist the most simple argument imaginable.
> [/B]


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## Patrick Bateman (Sep 11, 2006)

diegoejea said:


> As we say, this is a deep subject, and according to Lycan, for another thread! I agree, and I will finish right now.
> 
> But let me tell you that I am completely opposite to the theory applied by audiophlies to look for the real transduction.
> 
> ...


Not rude at all. Normally I skim posts on this board, because they're usually covering subjects that I know fairly well. But this is over my head, and *that's a good thing!* It's great to learn something knew.


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## Patrick Bateman (Sep 11, 2006)

lycan said:


> OK, it seems i _never_ learn to stay out these nonsense debates, but i just can't resist the most simple argument imaginable.
> 
> I'm sure we've all heard of the importance of "impulse response". The _impulse response_ of any linear, time invariant system is vitally fundamental ... it forms the very essence of convolution, which allows us to describe input/output relationships in the time domain, for _any_ class of input signal.


Considering how horrendous the impulse response of a speaker is when placed in a car, it's amazing that stereos are listenable at all. That's one of the reasons I'm so OCD about direcitvity. The measured response of loudspeakers in cars is HORRENDOUS. IMHO, psychoacoustics, and our brains ability to "gate" out late reflections, is the primary reason that car stereos can sound good. It's like the difference between talking to someone on a telephone or on a speaker phone. The speakerphone is capturing too much of the room sound, and making everything sound like ass. Our brains have the ability to gate out the room to some extent, and everything that we can do to improve performance in the first few milliseconds is key.


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## MiniVanMan (Jun 28, 2005)

Patrick Bateman said:


> But this is over my head, and *that's a good thing!* It's great to learn something knew.


Agreed!!

I can figure this out after going through it repeatedly, but the ability to articulate it like has been done so far is FAR beyond me. Very good stuff.


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## thehatedguy (May 4, 2007)

That is why Jeff is the mfing shizzle.


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## Patrick Bateman (Sep 11, 2006)

For the life of me, I can't figure out how John Atkinson can work at Stereophile without shooting himself in the head. His track record of technical reviews has been tireless and honest. Did anyone see his review of the Sony Playstation as a CD player? He did a nice job of putting it's measured performance into perspective, and it has bearing on this discussion.

Stereophile: Sony PlayStation 1 CD player

_"I wonder, therefore, if the "magic" of the PlayStation 1's sound lies not in its technical excellence but in the fact that it smears over and disguises much of what is wrong with typical CD sound quality, to which it adds a touch of low-level compression from the linearity error. Certainly, when I recently listened to a PS1 as the source in a system comprising an inexpensive Cayin tube integrated amplifier driving Definitive Technology Mythos ST speakers, it sounded relaxed and informative in a manner I would not have expected from this measured performance.?"_


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## Niebur3 (Jul 11, 2008)

Can I ask about something that was said in this thread....this is for anyone. This discussion is way over my head, but my question is: It was posted by several people about the off axis response of a speaker and debated about the good and bad of the response given trying to obtain a center image, well when we are tuning the system, don't most people just eq out the bad off axis frequencies, making the differences between different speakers irrelevant? Also, on another note, why would Scott post talking about the bad off axis response of a 28 and 32mm tweeter because of the large diameter, but then recommend using his 4" speaker to handle midrange and tweeter frequencies. Wouldn't that be a contradiction or am I missing something...just trying to understand all this better.


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## Patrick Bateman (Sep 11, 2006)

Niebur3 said:


> Can I ask about something that was said in this thread....this is for anyone. This discussion is way over my head, but my question is: It was posted by several people about the off axis response of a speaker and debated about the good and bad of the response given trying to obtain a center image, well when we are tuning the system, don't most people just eq out the bad off axis frequencies, making the differences between different speakers irrelevant? Also, on another note, why would Scott post talking about the bad off axis response of a 28 and 32mm tweeter because of the large diameter, but then recommend using his 4" speaker to handle midrange and tweeter frequencies. Wouldn't that be a contradiction or am I missing something...just trying to understand all this better.


It's not possible to EQ the off-axis response. You can only EQ the on-axis and the off-axis response simultaneously.

Here's a really quick summary on directivity - let me know if any of this doesn't make sense.


When the diameter of a sound wave is less than a diameter of the speaker that's producing it, the speaker will begin to beam. Doesn't matter if it's a subwoofer, a midrange, or a tweeter. For instance, a three inch soundwave is 4500hz. Therefore, above 4500hz, that speaker is going to beam. (This is a simplification BTW -a rule of thumb.)
When the speaker begins to beam, the energy is focused into the forward lobe, just like a flashlight focuses a beam of light.
You can use things like phase plugs and waveguides to manipulate this behavior.

I wish I could post a graph of two 3" woofers, one with a phase plug and one without. Unfortunately, I don't have the data handy. Here's the best that I can do on short notice:







This is the response of a 3" paper cone woofer from Tangband, which has a phase plug. See how the response is tipped up at high frequency? That's because it's beaming. The energy is being focused into the forward lobe.







This is the response of a 3" aluminum cone woofer from Peerless, which DOESN'T have a phase plug. See how the response is tipped up at high frequency? That's because it's beaming. You can see the beaming in the off-axis response - the energy is being focused into the forward lobe. See how it's more ragged than the TangBand? That's because we need a phase plug or a waveguide to "focus" the sound. Something like the lens on your camera.

I know that a lot of people talk about how speakers sound here, saying that one sounds better than another, or that one is more "musical." Once you wrap your brains around the directivity problem, you'll start to understand that a lot of our perception is based on the power response. Even tilting a speaker a few degrees can transform the entire soundstage.

At the same time, you MUST use EQ when you mess around with this stuff. Without EQ it's just a waste of time. The trick is juggling EQ, the on-axis and the off-axis response.


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## Niebur3 (Jul 11, 2008)

Patrick Bateman said:


> It's not possible to EQ the off-axis response. You can only EQ the on-axis and the off-axis response simultaneously.
> 
> Here's a really quick summary on directivity - let me know if any of this doesn't make sense.
> 
> ...


That does make sense, so is it possible to obtain a good center image (for both passenger and driver) in a car with having the speaker mounted on-axis? Also, can the dash, windshield and a pillar act as a wave guide of sorts in a vehicle where the mid range and tweeters are mounted on the dash on axis? I am trying to figure out an issue with extreme near side biased and if I can correct this without having to rebuild my pods so that the speakers are off axis. Just hoping someone can help.


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## Cruzer (Jul 16, 2010)

i know this is old, but i just wanted to say something as most of the thread was over my head anyways.

If what scott said was true, that if ur hearing something, its most likely not distortion, its all the effects and problems that occur when placing speakers in a car environment, then wouldn't it be true that u would want the lowest distortion speaker? because if it does have some slight audible distortion, that would just add to the noise, and problems u are hearing in a car environment, right?

the way i see it, u may not be able to make the car sound like your home, some things just might not be preventable, but distortion is. So why not prevent it, so it doesnt just add to the bad of a car environment?

Or at that point, the slight audible distortion wouldnt matter enough to worry?


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## Patrick Bateman (Sep 11, 2006)

Dryseals said:


> I've read Dr. Gedde's work, I'm not all that impressed with his findings and his papers leave little to shall we say, back up his work. Too many variables that he does not address.
> So to make it a little clearer, as I said before, hearing is learned. If you learn the particular sound of an instrument as in playing it for years, then you will notice the non-linear distortion from the speakers.
> Those extra little freqs do make a speaker seem brighter and for the most part, folks will enjoy them, it's pleasing to the ear. But if you are familiar with the sound they are trying to reproduce, you may or maynot be happy.
> 
> If you truely buy into Dr. Geddes work then there is no need for gear that can reproduce top notch sound. He kind of leans towards the Budwieser taste of building speakers, those for the masses.


If his speakers were the aural equivalent of Budweiser I doubt that rocket scientists at Princeton would be using his gear as a reference in their lab.

Princeton University rocket scientist boldly goes where no ears have gone before - Video | NJ.com


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## OSN (Nov 19, 2008)

Vote for the thread to be sticky'd.


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## Cruzer (Jul 16, 2010)

Funny thing is cajunner I found this thread by searching distortion. Somehow I too missed this thread, luckily I searched. Was a good read even though so much of it is over my head lol


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## peg_legs (Jan 31, 2011)

My 2 cents: I'm an engineer and don't care one bit about how a speaker measures. I only care about how it sounds. I use the measurements to help determine enclosure size and type, but will scrap an enclosure if it doesn't sound the way I like. Just like speaker placement, a raw driver's measurements on a bench don't change, but it sure will sound different in different locations in the listening environment. Bottom line is, 'tone" matters, measurements do not.

One other viewpoint:
I have a recording studio in my basement for my band. I use monitors with super flat response in a controlled listening area with room acoustics and reflections to "taste". I also have a booth that is extremely "dead" of reflections for when I need to hear certain details. I would never use either of these to ENJOY listening to the music, just to create it. 

My goals for my car and home are to enjoy the music and not to score a perfect measurement on distortion or a perfectly flat frequency response


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## peg_legs (Jan 31, 2011)

Cajunner, I really enjoy your posts  I completely agree on the first, raw and emotionally impactful effort. It is MY biggest nemesis getting those qualities when you have a musician trying to lay down a track playing along to earphones and trying not to screw up. all of the feel and emotion die. so many great things can happen live with musicians that feed off each other, but the recorded results of that are usually garbage. even as a listener, many venues are boomy, reflect horribly and smell like puke and booze . I have a secret fantasy to show up a week early to a venue I will play and treat the room. I actually do some basic treatments, but not enough.


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## Cruzer (Jul 16, 2010)

Talking about gigs, do u think their speakers have distortion other than when they are purposely doing so? Or even recording for that matter.

If they do have audible distortion, is it ok for our car speakers to have distortion?

Or would we want to have no audible distortion to still hear the correct sound the artist intended?


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## OSN (Nov 19, 2008)

cajunner said:


> what I'm getting at, is that the recent turn of wide-ranger hyper-focus and the subsequent rise or fall in audio speaker company jargon, is related to how much distortion is tolerable in the in-car experience.


Just curious, how many wide-band installations have you listened to? I have taken a real shining to the tang band w3 bamboo playing from 315 to 20k, on-axis. Easy as sin to get them right, their dispersion is laser beam narrow up high and the reflections are as non-existent as I have experienced. They don't work for a 2 seat car, but I haven't figured out a way to sit in both seats at once so I won't worry. Very coherent, and I love the vocals- it's like buttah.










They are very x-max limited, so they can't play the very lower end of the vocal range with a ton of volume, but I'm gonna play with a pair per side and see how she goes.


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## peg_legs (Jan 31, 2011)

thanks Cajunner!
Cruzer, You betcha! When I choose a speaker for guitar, i have favorites based on how they distort. When I need smooth mids and a nice high crunch I use mahogany guitars and Celestion Vintage 30 speakers. They break up in a very pleasing way. Other speakers give me a more "buttery tone" but less crunch. When I play bass, I like a big hairy all tube Ampeg for its thickness, grit and ballz, into a thick and buttery speaker cabinet from Jim Bergantino. When all tube, I mix a direct signal from the bass and a mic'd signal to add hair (distortion). 

I would love for the PA to reproduce the mic'd signal exactly, but it never does. It needs the direct signal to add back in the lower octaves and to make it more intelligible

Guitars just use a mic'd signal since the distortion of the speakers is part of the desired sound

PA speakers, and mics are also chosen for how they color the sound or not. In my humble opinion, every step along the chain from artists hands to listeners ears, is part of the coloration that ends in an enjoyable listening experience.

Long story short... distortion is part of the desired tone to create the sounds, and making it loud enough for the audience (PA) would hopefully distort none.

Think I may have just contradicted myself...


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## SSSnake (Mar 8, 2007)

> Long story short... distortion is part of the desired tone to create the sounds, and making it loud enough for the audience (PA) would hopefully distort none.


Actually it is a very good point. Most of all popular music includes distortion effects. However, we want to limit that distortion in the playback system. If we do, the playback can approach the musicians interpretation of the sounds they were attempting to create.


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## Cruzer (Jul 16, 2010)

SSSnake said:


> Actually it is a very good point. Most of all popular music includes distortion effects. However, we want to limit that distortion in the playback system. If we do, the playback can approach the musicians interpretation of the sounds they were attempting to create.


thanks that was what i was asking. mostly because if our speakers have an audible distortion naturally, when the signal asks them to play distortion, its always going to be more distortion than the artist intended.

now whether or not thats something to fret over, depends, but i read on here all the time everyone's drastic measures to get this "perfect" sounding setup, then i would assume low distortion would be a MUST in that case


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## peg_legs (Jan 31, 2011)

cajunner said:


> I've noticed this at a few live shows, where I can hear the on-stage amplification in some moments and only the stacks at others, I wonder if this is common or something that isn't supposed to happen...


Many musicians have moved to in ear monitors. It takes away much of the cross talk between mics, lowers the volume needed, provides hearing protection, and you can have your instrument in one ear and the rest of the band in the other or any combination of the different instruments at different volume levels. The real amps can be off stage and isolated from each other

I saw RUSH live in Pensacola, FL. Had horrible seats beside the stage and could only hear the drummer with an echo of the rest of the band. It's amazing how much the drummer does that gets lost in the mix. I was amazed all night

I feel like Im sidetracking this discussion, so stepping out


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## SSSnake (Mar 8, 2007)

> I saw RUSH live in Pensacola, FL. Had horrible seats beside the stage and could only hear the drummer


I have to comment on this... Hearing only the RUSH drummer is not necessarily a bad thing. Neil Peart is pretty amazing.


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## Wheres The Butta (Jun 6, 2009)

I got a lot out of this, I just wanted to say thanks. Subscribed.


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## Cruzer (Jul 16, 2010)

cajunner said:


> your assumptions are close, but consider this:
> 
> the distortion provided by the _reproduction_ system, is also a critical factor in how we perceive sound. Tube lovers are prey to this simple falsehood, the music moving through the iron creates distortion that is attributed to being of a rounding, warm, less clinical and inviting nature, and some of it is psychosomatic in origin as well.
> 
> ...


I dont have the knowledge to argue, or put forth a competitive dispute, but i will just say 1 thing. The whole warm, bright, etc. etc. unless it was meant by the artist to be "warm" its a characteristic of the drivers i have, and i dont like, nor want.

We look at bright, sharp, harsh etc. etc. as bad things (im referring to a tweeter) mostly because it sounds bad, hurts our ears, etc. So why is warm, and other terms like those a good thing? Sure it doesnt sound bad, we apparently like the sound, but if a speaker plays every, or most songs with the "warm" characteristic, to me its acceptable, but not ideal. Not how the music was meant to be heard, or played back.

No way does every artist, or most artist, play their music to sound "warm".

does distortion provide effects like warm, and/or harsh?


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## pionkej (Feb 29, 2008)

Cruzer said:


> I dont have the knowledge to argue, or put forth a competitive dispute, but i will just say 1 thing. The whole warm, bright, etc. etc. unless it was meant by the artist to be "warm" its a characteristic of the drivers i have, and i dont like, nor want.
> 
> We look at bright, sharp, harsh etc. etc. as bad things (im referring to a tweeter) mostly because it sounds bad, hurts our ears, etc. So why is warm, and other terms like those a good thing? Sure it doesnt sound bad, we apparently like the sound, but if a speaker plays every, or most songs with the "warm" characteristic, to me its acceptable, but not ideal. Not how the music was meant to be heard, or played back.
> 
> ...


It's a preference thing, not an accuracy thing. It would be like going to a Wolfgang Puck restaurant and ordering some Parmesan and Garlic fries that come with a side Horseradish Mayo and using Ketchup instead. He may not have intended for you to use Ketchup, but you chose it out of preference.

I posted early in this thread about how I like the "warm" sound of Morel drivers. I still do. I have also decided that I felt there were details that were being "smeared" because of the speaker choice so I spent a good amount of time looking for (and found) some old school JBL GTi series speakers. They are VERY similar to a pro-audio driver and VERY detailed. I will be using them as my midrange and after hearing them in a temp. setup off my home system I can't wait to get them in the car.

Also, "warm" is generally more easy to accept than "harsh" just because it feels like the name implies. Even though "warm" sounding speakers with even-order distortion isn't accurate, it is certainly better than something "harsh" or "bright" that is painful to listen to.


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## Patrick Bateman (Sep 11, 2006)

OSN said:


> Just curious, how many wide-band installations have you listened to? I have taken a real shining to the tang band w3 bamboo playing from 315 to 20k, on-axis. Easy as sin to get them right, their dispersion is laser beam narrow up high and the reflections are as non-existent as I have experienced. They don't work for a 2 seat car, but I haven't figured out a way to sit in both seats at once so I won't worry. Very coherent, and I love the vocals- it's like buttah.
> 
> 
> 
> ...


You should try some Unity horns, or a very very good small two-way. I think that a lot of the "magic" with full-range speakers is simply that the treble and the midrange are radiating from the same point in space. I think that people don't appreciate all the compromises that happen when your tweeter and your midrange get further and further apart. At the crossover point, even half an inch can change the midrange response dramatically, particularly off-axis. But these problems become a lot easier to deal with when you juggle crossover points and driver spacing carefully.









The midrange and tweeter that Snell uses is a good example of what I am talking about. Due to the small size and xover points, it virtually behaves like a single speaker.

This isn't a knock against full range speakers - I love 'em. Just saying that a very carefully engineered array can do the same thing.


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## Cruzer (Jul 16, 2010)

I know its all a matter of preference, and thats fine.

But when u go back to the food example. Im a picky eater, i almost always have to custom order any food item, any restaurant. But not so much because i like it better that way, or want it that way. I would love to eat it how it was made, as im sure everything included in the item, was put in the combination, for a good reason...

When it comes to distortion in the sound, i can choose willingly, and not from the point of view that one is basically useless to me as i couldnt use it, and wouldnt use it.

Ill be honest, ive probably never heard a really good set of speakers that have no audible distortion. Maybe i wouldnt like it, but i do know that most setups i have heard, im not impressed, i feel like there can, and should be more to the sound.

Im sure i could hear a nice setup, that sounds "warm" and enjoy it, and be impressed with it over the setups i have heard. But i bet a distortion free setup, would impress me most.

Were saying distortion is good, and ok within speakers, but what about subs? i dont know what most of u run, but i know a lot use AE IB, those have little to no distortion. So why is it acceptable with your front stage, but not the sub stage?

This is where i can relate. I had rockford subs, the distortion is bad the higher it plays. Then i got my polks and the distortion might still be there, but they can play higher than the rockfords, and without that horrible sound. I plan on getting some AE subs, and i wont play them any higher, but i bet i will again be impressed with the even lower distortion.

I take this as my front stage i would want it to have little to no distortion as well. maybe im wrong, maybe u cant compare that situation as subs play in general such an open area, where mids are in the doors, which is more challenging of a stage


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## sqnut (Dec 24, 2009)

Cruzer said:


> does distortion provide effects like warm, and/or harsh?


Yes, one of the effects of distortion is that it colours the sound one way or the other. All drivers distort at some point or the other.


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## Cruzer (Jul 16, 2010)

sqnut said:


> Yes, one of the effects of distortion is that it colours the sound one way or the other. All drivers distort at some point or the other.


Even a properly built speaker used in it's proper range distorts? Well then we shouldn't fret over distortion then

I know that's not exactly what u said, but i would say it's obvious every speaker distorts at some point.


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## BamaJohn (Mar 10, 2009)

Apologies for resurrecting an old thread, but after reading this thread and the 4" midrange test thread, I'm curious what you all think are the reasons for the differences heard in a well-done subjective listening test, say between the Legatia 4" and the Revelator 12M. I'm just genuinely curious as to what particular things in the design or engineering of one of these kinds of midranges makes the difference between "good" and "great." This thread discusses distortion and its effects--does that enter into it with these two, or do other factors dominate?


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## Cruzer (Jul 16, 2010)

lots of factors but apparently not distortion!


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