# The "essque" vs the "danger" of 6db slopes



## pionkej (Feb 29, 2008)

I see the "sound quality" of 6db slopes gets tossed around often (both here and audio in general) with the primary positive being there is less phase shift and therefore is much more natural sounding. The negatives of shallow slopes often seems to be ignored by those touted them...so I'm here to discuss that side.

So, in order to discuss this, we'll get a few things out of the way first:

-There are two commonly used forms of crossover: Butterworth (BW) and Linkwitz Riley (LR)
-They are measured in octaves, which is a doubling of halving of a frequency: 2000hz and 500hz are an octave above and below 1000hz. 
-Slopes start at 6db and work in iterations of that going up. 
-Order of slopes is based on the 6db rule so: 1st order=6db, 2nd=12db, 3rd=18db, 4th=24db, etc...
-LR crossover are made from cascading BW slopes and are only even order, so: BW1+BW1=LR2 (12db per octave)
-Crossover impart 45-degrees of phase shift per order, so: 1st/6db/45deg, 2nd/12db/90deg, 3rd/18db/135deg/ 4th/24db/180dg.

Next I want to share what I believe are the main contributors to phase problems. First is the phase shift of the speakers electric parameters (impedence). Then there is the phase shift of the crossover filter (mentioned above). Then there is the room (which is speaker to speaker interactions and reflections).

Now I'm going to run some math comparing my preferred LR4 (24db slope) to the "essque" BW1 (6db slope). I'm going to use the crossover between midrange and tweeter and I'm going to use 2khz as the crossover point (mostly because I already did the math in another thread).

Let's use the Vifa XT25 tweeter as an example. The impedance peaks around 500hz (which has an associated phase shift). Let's get really extreme and use a 2khz crossover on this tweeter (though general listening impressions indicate 3khz+ is a better decision). We put a LR4 (24db linkwitz-riley) crossover on it. The roll-off for LR is to be down 6db at the crossover and then fall an additional 24db (makes sense) per octave after that. 500x2=1000x2=2000. We are two octaves away from Fs with a 2khz crossover. (-6db at crossover)+(-24db first octave)+(-24db second octave) means the tweeter is *54db lower *at 500hz than it is at 2khz. NOTE: I generally consider a speaker to be a non-factor on another speaker once it is 30db down in output (which is exactly 1 octave down using LR4). How much influence do you think a phase anomoly in the tweeter at -54db will impart on the midrange it's mating up to??? The answer is it's not even a blip on the radar...especially compared to what a simple single reflection can do with the midrange itself at the same frequency.

So the impedance of the driver seems to be a non-factor with LR4. What about the phase change of the crossover itself? Remember when I listed that above and showed LR4 is 180degrees? 180degrees of phase difference between two speakers means they cancel!!! BUT...a LR4 low pass on my midrange and an LR4 high pass on my tweeter means 180degrees+180degrees=360degrees. Phase of a speaker is measured just like a circle, 0degrees and 360degrees are both at the top of the circle...so 360degrees of phase shift means they are back in phase! I suppose that means the crossover itself is a non-factor as well.

What I'm left with is the room and speaker interactions. Speakers will ALWAYS interact with the room they are in, no crossover will change that. Speakers will ALWAYS interact with each other at the frequencies they share, a crossover CAN change that. With LR4, the signal is down 30db on octave away from the crossover point. So for 2khz, the tweeter and midrange really only interact from 1khz to 4khz using a LR4 crossover. 

So what about that 6db crossover? One thing about it is true...by itself it imparts less phase shift on the speaker. LR4 has 180deg while BW1 only has 45deg. That HAS to sound more natural right? 

Well, I mentioned that the LR4 crossover is down 54db at 500hz with a 2khz crossover point (two octaves away). Let's see how long many octaves it takes to get the level down 54db using a BW1.

(-3db--Butterworth is only -3db at crossover)+(-6 first octave)+(-6 second octave)+(-6 third octave)+(-6 fourth octave)+(-6 fifth octave)+(-6 sixth octave)+(-6 seventh octave)+(-6 *eighth octave*)=51db (not quite 54, but close enough).

Wow, EIGHT OCTAVES to get down 51db. But eight octaves can't be THAT much more than the two LR4 needed...can it... 

Let's start at 2khz and see:

2000/2=1000/2=500/2=250/2=125/2=62.5/2=31.25/2=*15.5hz!!! *

So the tweeter on a BW1 crossover is playing sub frequencies by the time it's level is reduced <almost> as much as the LR4 crossover is at 500hz. Now, we all know that a tweeter isn't likely to pay 15.5hz even at that low level...but by using that crossover your asking it to try to. So there is only 45degrees of phase shift on the single driver, but you are easily playing through the speakers impedance (fail on point 1), you are at 90deg of phase shift (45deg high pass and 45deg low pass--OR--not really in phase or out of phase)(fail on point 2), and your speakers are interacting with each other for about 6 octaves instead of a single octave (fail on point 3). This doesn't even account for the fact that you are likely killing your driver from pushing it well pasts it's mechanical limits.

Now, a proponent of BW1 slopes would tell me they aren't stupid and would simply cross over higher to avoid the impedance and excursion issues. Ok, so let's do that. To be down 54db at 500hz (which should avoid the impedance and excursion issues as well as a LR4 crossover at 2000hz would), we simply need to follow the same rule but go UP eight octaves from 500hz instead of down eight from 2khz.

500x2=1000x2=2000x2=4000x2=8000x2=16000x2=32000x2=64000x2=*128,000hz.*

Sweet, so all you need to do to avoid the same problems a LR4 can do at 2khz is cross your tweeter at...128khz??? I suppose it's a good thing most active DSP's let you go over 20khz (hint: they don't) since you'd need to go up six times higher than that to start the roll-off.

I could go on a bit more about potential issues with shallow slopes, but for now I'll leave it at this. If you read all this and still down believe me. Set your tweeter crossover to something "normal" (2khz to 4khz) and a LR4 crossover. Turn the volume up as loud as you can. Now use the same crossover and change it to BW1 and crank on it again. For 90% of the listeners, the question won't come down to which is better, but do you turn the volume back down quickly enough to avoid blowing your tweeters.

Oh, and none of this means that a system using 6db slopes can't be done (or hasn't been done) well. The point is that it seems unbelievably difficult to me to even try and do it well. The point is that it IS unbelievably EASY to get WRONG (and easy to blow speakers doing it) and yet people recommend it and others try it all the time.


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## sankar (Sep 23, 2013)

Very well explained! Thank you!


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## Mic10is (Aug 20, 2007)

POinky--you did the near impossible. This thread made me smile.


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## ErinH (Feb 14, 2007)

Supplemental reading from a company that is well regarded and makes their money from developing and producing DSPs:
Linkwitz-Riley Crossovers: A Primer


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## highly (Jan 30, 2007)

Very well stated as always, John! Thanks for the clear and concise retort to the argument for shallow slopes.

-T


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## Neil_J (Mar 2, 2011)

Very well put, pionkej. I can't find any fault in how you explained it (and I tried to find something to nit pick).


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## sman101 (Nov 1, 2013)

Sound environment is everything!


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## Hanatsu (Nov 9, 2010)

I prefer L-R 4th order. Using 1st order filters demand extremely well behaved drivers. Even then, 1st order filters are not fit to use in car audio, considering the level we're listening at. The level at tweeter Fs will not be enough attenuated in many cases...

Sent from my Samsung Galaxy 3 via Tapatalk.


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## strakele (Mar 2, 2009)

First, I agree with everything posted.

Though just to add to the discussion, I don't think we need to worry about something as far down as 54dB. If we take a more reasonable 24dB down, we only need to cross a tweeter at 8K/6dB to be down 24dB at 500Hz. 

If you're giving a tweeter 30 Watts (good for a pretty darn loud 100dB from most tweeters), by the time you're 24dB down at 500Hz, you're looking at barely 1/10 of 1 Watt. And by the time you're into sub-bass frequencies, you're looking at 3/1000 of 1 Watt. You can feed a tweeter 20Hz all day if it's only .003W.

But obviously as stated, there are a lot more reasons not to use 1st order crossovers.


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## minbari (Mar 3, 2011)

depends on what you are using. There are time it helps.

I went from LR4 at 1300 hz for my HLCDs to a 6db at 2800hz. much more natural sounding and the higher initial crossover freq helped to naturally tame the 2500hz hump in response.

The HAT imagines are well regarded and only use a simple 6db crossover.


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## Kevin K (Feb 11, 2013)

Interesting.


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## highly (Jan 30, 2007)

Kevin K said:


> Interesting.


In what way?


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## Kevin K (Feb 11, 2013)

What John states makes a great deal of sense, but minbari states the 6db slope helped cure some in vehicle issues. There's a MECA judge that likes using 6db slopes as well.

I use 24db slopes.


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## Neil_J (Mar 2, 2011)

Kevin K said:


> What John states makes a great deal of sense, but minbari states the 6db slope helped cure some in vehicle issues. There's a MECA judge that likes using 6db slopes as well.


My takeaway was that John was getting at the fact that the whole thing is complicated and you can't make blanket statements that it works or doesn't. It depends on a lot of things. It can be done in certain cases but can't be done in a lot of other cases. And likely some people are using 6dB slopes when they shouldn't be, and aren't any the wiser. Just be cautious and know what you're doing! /thread


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## highly (Jan 30, 2007)

Kevin K said:


> What John states makes a great deal of sense, but minbari states the 6db slope helped cure some in vehicle issues. There's a MECA judge that likes using 6db slopes as well.


Well, that's not exactly what I read from minibari. He stated that his opinion was that in one case a shallower slope placed higher in the passband corrected a known problem while meeting his subjective preference. He didn't mention if in fact proper equalization of the problematic frequencies were attempted with the lower, steeper crossover or if changes were made to the mating driver... so I find this more an anecdotal 'maybe' than clearly qualified 'proof'. No offense at all meant, minibari. No doubt it can be shown either way that the driver will play much more low frequency information and bring into play all that involves.

-T


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## pionkej (Feb 29, 2008)

strakele said:


> First, I agree with everything posted.
> 
> Though just to add to the discussion, I don't think we need to worry about something as far down as 54dB. If we take a more reasonable 24dB down, we only need to cross a tweeter at 8K/6dB to be down 24dB at 500Hz.
> 
> ...


You're completely right Grayson that 54db is not needed. I built this thread using some information I'd already done the math for in another thread (cheated a bit to save some time). That thread was referencing the Vifa XT25 and it's 500hz resonance peak. Since 2khz is a pretty low point for crossing that tweeter and is exactly 2 octaves from 500hz, I used it as my example. It just happens LR4 is 54db down at that point and so I based everything else off of it.

I typically use 30db down as the cutoff point for worrying about a speaker, but the difference between 24db and 30db is pretty negligable (unless you are using 6db slopes ), so we agree there too.



minbari said:


> depends on what you are using. There are time it helps.
> 
> I went from LR4 at 1300 hz for my HLCDs to a 6db at 2800hz. much more natural sounding and the higher initial crossover freq helped to naturally tame the 2500hz hump in response.
> 
> The HAT imagines are well regarded and only use a simple 6db crossover.


I also agree with this statement. Sometimes using a shallower slope can lead to a "more natural sound", but I'd bet there is a reason behind that! I'd bet that if you measured the speaker, at low volume, with no crossover, you would see the speaker probably has slight boost on the bottom followed by a steep natural roll-off. If you go low and use and LR4 with that, you are cascading the two and end up with something much steeper than what LR4 is on paper. In fact, my target is always LR4 COMBINED RESPONSE (I measure the speaker and then add the electric filter in to make a LR4 slope--and right now my midrange has a 300hz/6db slope on it to make a 140hz/24db measured roll). 

I appreciate both posts to point out there are exceptions to the rule. It even allowed me to share I participate in those exceptions. The difference here is that neither of you are new to this or inexperienced to tuning and you aren't going out promoting 6db slopes wholesale. It all ties back to my first post though, if someone is saying that "sound quality" lies in the area of 6db slopes I'll still argue the "dangers" of getting it wrong are much greater than getting it right.


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## strakele (Mar 2, 2009)

Yep, we're definitely on the same page. Just wanted to add some power numbers to the discussion.

FWIW I've never used a 6dB slope in any of my processors and don't really intend to, but for a while I ran a small tweeter in parallel with my midrange using a simple capacitor 1st order highpass at 14K and it worked pretty well.


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## pocket5s (Jan 6, 2012)

pionkej said:


> * In fact, my target is always LR4 COMBINED RESPONSE (I measure the speaker and then add the electric filter in to make a LR4 slope--and right now my midrange has a 300hz/6db slope on it to make a 140hz/24db measured roll).*


I think it is worth highlighting this as it might get lost in the conversation a tad, especially for the new folks. If someone new to the hobby happens to ask you at a show what XO you used and you had said 6db, they won't understand why you chose it, i.e. for the combined 24db response (in that particular example). They would just think "well John used a 6db at X frequency, so I should too", and be completely going down a potential wrong path. 

By the same token, perhaps reading that a particular home or pro-audio piece is using a 6db slope is not getting the full information. Perhaps it was chosen for the same reason, a targeted higher slope.


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## strakele (Mar 2, 2009)

^^Very important point that deserves close consideration.


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## Kevin K (Feb 11, 2013)

Like I said above, very interesting indeed.
That's why I like this hobby/sport, so much can be learned and to study as well as the enjoyment of it at the same time.


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## ErinH (Feb 14, 2007)

Just something to toss in here...

In some cases you can even use a LP crossover to tailor the system roll off. Ie; using a variable Q filter at 7khz to gently slope a rising tweeter response (or simply to target a curve).


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## pocket5s (Jan 6, 2012)

bikinpunk said:


> Just something to toss in here...
> 
> In some cases you can even use a LP crossover to tailor the system roll off. Ie; using a variable Q filter at 7khz to gently slope a rising tweeter response (or simply to target a curve).


I just heard minds being blown... 

imagine the talks "holy hell so-and-so put a low pass xo on his _tweeter_"


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## strakele (Mar 2, 2009)

On the 'acoustic slope' topic, I do have a question.

If you use a 6dB slope in your DSP in concert with the natural roll off of the speaker to create a 24dB acoustic slope, does that necessarily result in the same phase shift that there would be using a 24dB slope in the DSP?


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## sqnut (Dec 24, 2009)

I use 4th order slopes all round. Like mentioned in one of the posts, steep slopes gives a narrow xover zone where you managing both sets of drivers to maintian an overall smooth response / transition. 

A lot of the passive xovers, cross in the 2-3khz range and use 6-12db on the tweets. Probably done to manage the beaming on the near side mid bass with typical door installs. The typical 0.75-1" tweeter is going to sound a bit harsh when its down only 12 db at 1khz.


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## Neil_J (Mar 2, 2011)

bikinpunk said:


> Just something to toss in here...
> 
> In some cases you can even use a LP crossover to tailor the system roll off. Ie; using a variable Q filter at 7khz to gently slope a rising tweeter response (or simply to target a curve).


I'm guilty of that  I'm using a 6 dB low pass on my tweets right now to tame them a bit at the top end. So yea throw me in the 6 dB EssQueue bandwagon.


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## BuickGN (May 29, 2009)

Good read, thanks for the information. I'm going to have to read it all again when I get home. 

I ran my system with 6db slopes for a while. I have excursion videos of the midrange and midbass on these slopes, I felt sorry for my midranges. I've settled on 48db myself. It's just easier for me. It seems like less to tune; it sounds better right out of the box.


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## pionkej (Feb 29, 2008)

strakele said:


> On the 'acoustic slope' topic, I do have a question.
> 
> If you use a 6dB slope in your DSP in concert with the natural roll off of the speaker to create a 24dB acoustic slope, does that necessarily result in the same phase shift that there would be using a 24dB slope in the DSP?


Software like REW and Omnimic derive phase from amplitude (frequency response) over time. 

And here is a definition I quickly found online: "Measurement of the time delay between two periodic signals. The phase difference between two sinusoidal waveforms that have the same frequency and are free of a dc component can be conveniently described as shown in the illustration. It can be seen that the phase angle can be considered as a measure of the time delay between two periodic signals expressed as a fraction of the wave period. This fraction is normally expressed in units of angle, with a full cycle corresponding to 360°."

So my answer is yes.  The truth is, you measurement system isn't going to know if you have: a perfectly flat speaker that then needed a 24db slope to hit target, a speaker that rolls off at 12db and a crossover with a 12db slope to sum 24db, or a speaker that rolls off at 24db and no crossover needed whatsoever. If these three scenarios measure to where they lie measure the same...the phase will show to be the same as well.

Here is the next caveat (and this plays back into why 6db slopes don't matter), we humans aren't very good at reconizing phase shifts...as long as they are smooth in transition. One of the arguments for 6db slopes are the minimum phase "benefits" they impart (meaning there is no significant phase shift in the system response). The truth is, playback can pass in and out of phase and not be noticed. We don't need minimum phase and simply need to make sure there is no abrupt change in phase. One thing that makes that difficult to achieve is lots of driver to driver interaction (which 6db slopes have). 

Here is a great article. The whole thing is great, but not short either, so you can just jump to Phase Audiblity if you want.

Phase, Time and Distortion in Loudspeakers


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## strakele (Mar 2, 2009)

Cool, thanks.


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## decibelle (Feb 17, 2011)

Great thread John, very well explained. Hats off to you for actually typing all that out  Sub'd for further discussions here. Wonder if anyone's going to give a rebuttal...


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## thehatedguy (May 4, 2007)

This is from memory last year...

When I was playing with PCD and lspCAD, the 6 db electric filter combined with the horn's roll off to make a 24 dB acoustic slope did not have the same phase characteristics as a 24 dB electric filter at the target filter point...and out of passband.

Linkwitz said he couldn't hear the phase differences...but a lot of people say they can. But why should Linkwitz admit that he could...he does have a slight vested interest in the debate.


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## 07azhhr (Dec 28, 2011)

pionkej said:


> -LR crossover are made from cascading BW slopes and are only even order, so: BW1+BW1=LR2 (12db per octave)


First nice write up John.

Second my Zapco DSP has the option of choosing LR or BW for any of the 6/12/18/24 slope options and when switching between them you can hear (and see in the displayed graph) the difference in the cut off. So my question is do the rules change when using electronic filters or is their some other kind of relationship going on here?





bikinpunk said:


> Just something to toss in here...
> 
> In some cases you can even use a LP crossover to tailor the system roll off. Ie; using a variable Q filter at 7khz to gently slope a rising tweeter response (or simply to target a curve).


I did this but only to one side for my last pillar setup. With the passenger side tweet being near zero degrees off axis and the drivers side being just shy of 30 degrees there was a measurable (and audible) difference in the response at the drivers seat that was proving to be very challenging to resolve with EQ. So I experimented with using a BP setup on the passenger side. It seemed to help a lot. I was never truly happy with that install though and because of that very issue I chose to get both tweets to be at the same axis to me this time around. In doing so I also ended up with them being at the same axis to the passenger seat as well. Huge bonus. Now I just shape the roll off more equally on the eq. 



I am still learning and threads like this help a lot.


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## ErinH (Feb 14, 2007)

07azhhr said:


> First nice write up John.
> 
> Second my Zapco DSP has the option of choosing LR or BW for any of the 6/12/18/24 slope options and when switching between them you can hear (and see in the displayed graph) the difference in the cut off. So my question is do the rules change when using electronic filters or is their some other kind of relationship going on here?



Check out the link I posted toward the beginning of this thread there's some REALLY good info there. And itay answer your question. If you look at Rane's site there are quite a bit of tech docs and I'm pretty sure they have another one on crossovers. I'm on my phone now and it's a pain to deal with. Otherwise I'd find it and link it.


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## pionkej (Feb 29, 2008)

07azhhr said:


> Second my Zapco DSP has the option of choosing LR or BW for any of the 6/12/18/24 slope options and when switching between them you can hear (and see in the displayed graph) the difference in the cut off. So my question is do the rules change when using electronic filters or is their some other kind of relationship going on here?


Nope, it's exactly what it should be. Butterworth slopes start to roll off earlier and are -3db at the crossover point. Linkwitz are steeper and are -6db. This makes sense if you consider Linkwitz is cascaded (added) Butterworth filters. -3db and -3db stacked should make -6db.

So...

BW1 is -3db at crossover and -6db every octave after
BW2 is -3db at crossover and -12db every octave after
LW2 is -6db at crossover and -12db every octave after (made from -6db and -6db)
BW3 is -3db at crossover and -18db every octave after
BW4 is -3db at crossover and -24db every octave after
LW4 is -6db at crossover and -24db every octave after (made from -12db and -12db)

And it continues from there with Butterworth going up every -6. Linkwitz can only exist from cascading Butterworth. So Butterworth would be -30,-36,-42,-48 but the next Linkwitz is 36 (-18 and -18) and then 48 (-24 and -24).


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## Patrick Bateman (Sep 11, 2006)

It's easy to overdrive a tweeter with a first order filter.








For instance, the Vifa XT25 has a radiator that's TINY. It's not even half a square inch, because a big part of it is the phase plug (which isn't radiating.)

So the Vifa XT25 is a terrible candidate for a first order filter.

Or is it?

















It doesn't take much of a waveguide to add some gain to a tweeter. 1500hz is just 9" long; this means that a waveguide about 2.25" deep will add "gain" to a tweeter down to 1500hz.

Now if you put a first order filter in front of that tweeter, the response is basically flat. (The waveguide adds gain, the filter takes it away.) And the phase response of the filter is dictated by response shape.

Long story short -

With a waveguide you can use a filter that's a 2nd order electrical, but the resulting response shape will be first order acoustic, and so will the phase response.

It is true that below 1500hz the filter order will start to get steeper, because the waveguide isn't adding gain. So the phase response below 1500hz won't be perfect.

But I'm mostly worried about the phase response at the crossover point. With a 3khz crossover and first order acoustic filters, the tweeter and midrange will 'blend' nicely in the time domain.




Here's a question:

Linkwitz Riley 4th order crossover are probably the most popular crossover in the world.
If they're so great, why doesn't Linkwitz use them in his latest speaker? (He uses first order on the tweeter of his latest speaker.)
If first order sounds so bad, then why are Thiel, Vandersteen and Dynaudio so popular? (All three companies use first order filters exclusively. In fact a lot of the engineering in Dynaudio and Morel drivers is to accomodate the high excursion, high power handling and wide bandwidth that's needed for first order filters.)


I'll concede that high order filters raise power handling.
But I have lots of other tools in my toolbox to raise power handling. Everything from arrays to large voice coils.
But I only have two tools that can fix the phase response. The first is low order filters, the second is DSP.


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## Patrick Bateman (Sep 11, 2006)

thehatedguy said:


> This is from memory last year...
> 
> When I was playing with PCD and lspCAD, the 6 db electric filter combined with the horn's roll off to make a 24 dB acoustic slope did not have the same phase characteristics as a 24 dB electric filter at the target filter point...and out of passband.
> 
> Linkwitz said he couldn't hear the phase differences...but a lot of people say they can. But why should Linkwitz admit that he could...he does have a slight vested interest in the debate.


I've generally found that the best defense of phase response comes from John Dunlavy and Richard Vandersteen. It's kind of mind boggling that Tom Danley has stuck to his guns and uses phase-accurate speakers in the prosound world, considering that prosound is all about power handling.

This Stereophile interview with the late great John Dunlavy covers it nicely:

Loudspeaker designer John Dunlavy: By the Numbers... | Stereophile.com

Dunlavy also wrote some great stuff on rec.audio before he died.

Also, I totally admit that Rephase is the future. In five or ten years we won't need to use low order xovers to fix phase, we'll just use DSP to fix high order xovers.


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## Neil_J (Mar 2, 2011)

Patrick Bateman said:


> Here's a question:
> 
> Linkwitz Riley 4th order crossover are probably the most popular crossover in the world.
> If they're so great, why doesn't Linkwitz use them in his latest speaker? (He uses first order on the tweeter of his latest speaker.)
> If first order sounds so bad, then why are Thiel, Vandersteen and Dynaudio so popular? (All three companies use first order filters exclusively. In fact a lot of the engineering in Dynaudio and Morel drivers is to accomodate the high excursion, high power handling and wide bandwidth that's needed for first order filters.)


Yea but come on. They don't go at it all willy-nilly. They're in the somewhat small group that can actually pull of a 6 dB filter. They understand audio holistically, rather than those that just go to a forum and ask "what type of tweeters and crossovers should I use?". Which is again, what I think the OP was getting at. He didn't say that it couldn't be done. He said there were dangers and that there were safer ways to cross your speakers over in a car environment. And I'd agree there. LR4 is probably where most of the non-gurus should start. You shouldn't start playing with 1st order filters in a car (and touting their SQ magic) until you really know what's going on. Like Linkwitz et. al. do.


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## 07azhhr (Dec 28, 2011)

pionkej said:


> Nope, it's exactly what it should be. Butterworth slopes start to roll off earlier and are -3db at the crossover point. Linkwitz are steeper and are -6db. This makes sense if you consider Linkwitz is cascaded (added) Butterworth filters. -3db and -3db stacked should make -6db.
> 
> So...
> 
> ...


I have the option of 6db LW which I am assuming should be -6db at the xo point then just like BW1, -6db every octave after as well as 18db LW. But I see that you omit the LW1 and LW3 as if they can not exist. Zapco does not seem to agree with that. 

I understand that BW is 3db down at the initial XO point while LW is 6db down. What I am questioning is why would that fact have any affect on how many db down either xo type is at each octave after that. Like I said my DSP allows me to choose any of the slopes 6/12/18/24 as LW or BW.


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## ErinH (Feb 14, 2007)

If for no other reason than avoiding additional combing issues outside the passband and between speakers, I don't believe shallow slopes have a place in car audio.


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## Neil_J (Mar 2, 2011)

07azhhr said:


> I have the option of 6db LW which I am assuming should be -6db at the xo point then just like BW1, -6db every octave after as well as 18db LW. But I see that you omit the LW1 and LW3 as if they can not exist. Zapco does not seem to agree with that.


Lol. Where does Zapco mention 1st order Linkwitz Riley filters? Not to diss on Zapco any. But I've read a LOT of books on DSP and filtering and I've NEVER seen anything other than LR2, LR4, etc. But please correct me if I'm wrong.



07azhhr said:


> I understand that BW is 3db down at the initial XO point while LW is 6db down. What I am questioning is why would that fact have any affect on how many db down either xo type is at each octave after that. Like I said my DSP allows me to choose any of the slopes 6/12/18/24 as LW or BW.


Well the math just works out. If you cascade two filters (put them in series) then the slopes will be steeper. That's just how it is. I can point to all sorts of books that explain this better than I can. I've actually gone through the trouble of designing these filters in Labview, and can say there's not really any smoke and mirrors going on. You can do BW1, BW2, BW3, BW4..... Cascade two BW1's and you get an LR2. Cascade two BW2's and you get an LR4. Cascade two BW4's and you get an LR8. Don't take my word for it. Try it out in Matlab or Labview. 

I've no idea why your Zapco is coming up with an LR1 or LR3. Would love to hear anyone else's thoughts on that.


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## 07azhhr (Dec 28, 2011)

Neil_J said:


> Lol. Where does Zapco mention 1st order Linkwitz Riley filters? Not to diss on Zapco any. But I've read a LOT of books on DSP and filtering and I've NEVER seen anything other than LR2, LR4, etc. But please correct me if I'm wrong.
> 
> 
> Well the math just works out. If you cascade two filters (put them in series) then the slopes will be steeper. That's just how it is. I can point to all sorts of books that explain this better than I can. I've actually gone through the trouble of designing these filters in Labview, and can say there's not really any smoke and mirrors going on. You can do BW1, BW2, BW3, BW4..... Cascade two BW1's and you get an LR2. Cascade two BW2's and you get an LR4. Cascade two BW4's and you get an LR8. Don't take my word for it. Try it out in Matlab or Labview.
> ...


It is the options in their processors. I can select what slope 6db if you will then I have a BW option and a LW option. 


I just read the link that Erin posted earlier and see about the using two BW's in series and get that part as far as passives are concerned. But in the DSP world can there actually be a possibility of the effects of the LW being applied to a 6db or 18db slope?


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## 07azhhr (Dec 28, 2011)

Here is a pic of the GUI. Just below the eq section is the xo section. The slopes avail are separate from the filter type. They are not mentioning LR1 or LR3 specifically but it is an option to select 6db or 18db and still select the filter type as LW.

Don't mind that 12db was selected in that pic. That pic was being used to help someone figure out a problem with their setup and was just handy in my PB account.


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## Neil_J (Mar 2, 2011)

07azhhr said:


> Here is a pic of the GUI. Just below the eq section is the xo section. The slopes avail are separate from the filter type. They are not mentioning LR1 or LR3 specifically but it is an option to select 6db or 18db and still select the filter type as LW.
> 
> Don't mind that 12db was selected in that pic. That pic was being used to help someone figure out a problem with their setup and was just handy in my PB account.


I think that's a software bug. If have to see the frequency response and phase response measurements to see what exactly the software is doing. But it wouldn't be the first DSP with weird quirks like that.


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## SPLEclipse (Aug 17, 2012)

Switch back and forth between BW and LR to see if there's any change in the graphical representation. I bet there isn't, but BW should have a larger peak in the middle of the passband if there is.

I'm guess it was more complicated (and potentially frustrating for consumers) to pop up a text box or grey-out the LW option than just leaving it in and just routing it as a BW.

My take on the matter is this: I think cohesion between drivers is much, much more easily accomplished when out-of-band artifacts are virtually eliminated. Once you've done that, you've eliminated a variable and are free to experiment with crossover points and TA more easily and with more consistent results. This applies to cars primarily.


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## Patrick Bateman (Sep 11, 2006)

bikinpunk said:


> If for no other reason than avoiding additional combing issues outside the passband and between speakers, I don't believe shallow slopes have a place in car audio.


I don't agree with that statement.
I think phase is important and the easiest way to get the phase response right is to use first order crossovers.

Having said that, if you can't get the drivers within one wavelength of each other at the xover frequency, *do not bother with first order slopes.*

When two speakers are using first order slopes, each driver will generate significant SPL out of it's passband. Due to this, if they're not spaced closely, the advantages of 1st order filters are moot.

For instance, with an xover point of 3khz you'd want your midrange and your tweet within 4.5" of each other. This isn't hard to do with the small midranges that I use, but if you try to do it with a 6.5" woofer, it just won't work. (Unless you happen to have a VERY beefy tweeter than can handle a first order xover at 2khz.) Waveguides help.


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## copperears (Sep 2, 2010)

The filler drive setup I use at home is not for high volume listening. What I am working on for my 4Runner I doubt will ever be realized. The volume needed is brutal on the 6 db driver. But a compromise, like a lot of high end speaker builders use is to get the phase right and blend your drivers with lower order filters and then when they are attenuated enough to add another filter section (elliptical).

I dislike high Q systems, and high order filters to me, just seem to ring more. Of course the only place I can really notice either one of these peeves is at lower volumes at home. On the road, both points are relatively baseless.


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## highly (Jan 30, 2007)

SPLEclipse said:


> <snip>
> My take on the matter is this: I think cohesion between drivers is much, much more easily accomplished when out-of-band artifacts are virtually eliminated. </snip>












Agreed.


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## sqnut (Dec 24, 2009)

bikinpunk said:


> If for no other reason than avoiding additional combing issues outside the passband and between speakers, I don't believe shallow slopes have a place in car audio.


From a tuning perspective, I agree with this 100%. In a car for all the instances where 6db slopes supposedly work and no matter how good it sounds, it will sound better with steeper slopes and the right tuning.


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## BigRed (Aug 12, 2007)

I think some may find the value in understanding the difference between ACOUSTIC slope and ELECTRONIC slope. They are not always the same when measuring.


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## 07azhhr (Dec 28, 2011)

SPLEclipse said:


> Switch back and forth between BW and LR to see if there's any change in the graphical representation. I bet there isn't, but BW should have a larger peak in the middle of the passband if there is.
> 
> .


I opened it up and played with it. It did not move on the graph when 6 or 18 were selected. I guess I never payed too much attention when I was trying 6 or 18 slopes lol.


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## ErinH (Feb 14, 2007)

BigRed said:


> I think some may find the value in understanding the difference between ACOUSTIC slope and ELECTRONIC slope. They are not always the same when measuring.


that's actually what John addressed in an earlier post, which Robert quoted. 



pionkej said:


> In fact, my target is always LR4 COMBINED RESPONSE (I measure the speaker and then add the electric filter in to make a LR4 slope--and right now my midrange has a 300hz/6db slope on it to make a 140hz/24db measured roll).


And, I do agree. I have a target 2.8khz acoustic slope. But to achieve that, it took some different crossover points in my car than is normal for most; especially considering the horn loaded nature of my Kefs.


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## BigRed (Aug 12, 2007)

^^ my point was to investigate why there is a difference and understanding it


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## ErinH (Feb 14, 2007)

SPLEclipse said:


> My take on the matter is this: I think cohesion between drivers is much, much more easily accomplished when out-of-band artifacts are virtually eliminated. Once you've done that, you've eliminated a variable and are free to experiment with crossover points and TA more easily and with more consistent results. This applies to cars primarily.


I agree. That's pretty much what I was saying earlier with this comment:



bikinpunk said:


> If for no other reason than avoiding additional combing issues outside the passband and between speakers, I don't believe shallow slopes have a place in car audio.





People like to think outside the box and go with these home audio solutions. Though, sometimes they forget the most important part: they are IN a box. The car is a different animal and while a lot of acoustic science is shared between car and home, there are a lot of caveats where the user has to consider the tradeoffs. For one, lower order slopes means more shared information in a VERY reflective environment which can lead to additional combing outside the passband. And trying to fix these kind of things can be a nightmare. I've heard a few cars that I had to give up on because I couldn't do anything with the DSP to fix the crap that was happening above or below a speaker's crossover point.


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## BigRed (Aug 12, 2007)

Let me summarize: Car Audio AIN'T Home Audio 

I remember calling Orang County Speaker Repair to service a JBL 2118. On the phone they were all excited about asking me what kind of box i was putting it in and how much power etc. When I told them it was going in a car, the air immediately deflated out of the room. He went "ehhhhhh". He then asked me why bother in such a reflective environment.

Home audio guys think we are crazy! I think they are right  lol

sorry for the de-rail. carry on gents!


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## 14642 (May 19, 2008)

strakele said:


> On the 'acoustic slope' topic, I do have a question.
> 
> If you use a 6dB slope in your DSP in concert with the natural roll off of the speaker to create a 24dB acoustic slope, does that necessarily result in the same phase shift that there would be using a 24dB slope in the DSP?


And this is the better question ^^

The only crossover and the only phase shift we hear (if we hear the pahse shift) is the ACOUSTIC response. The electrical filters only matter because they shape the acoustic response. The alignment of the electrical filters doesn't mean ANYTHING unless you're simply designing electrical filters. 

Manufacturers use a single cap on a tweeter in a coaxial speaker because it's easy to attach to the basket and it's cheap. Better speakers more often use a second order filter for a lower filter F3 and a better blend between tweeter and mid. 6dB crossovers in a car are not BETTER. They are CHEAPER and EASIER. 

ALl of this hoopla over introducing phase errors is ridiculous. The phase you hear is the result of the combination of the drivers, the filters and the reflections. Get over it. The phase response of a car audio system is seriously ugly. If the frequency response sum of the two filtered drivers includes a big phase-induced suckout, then that should be fixed by polarity or by choosing a different filter to change the acoustic response. That's the only real consideration that ought to be paid to phase--well, and making sure that left and right are connected in the proper polarity. Without that, there won't be a center image. 

Delay is also a phase adjustment of sorts and should be adjusted to m ake arrival times similar, especially in the midbass/midrange. 

I can't think of any reason that 6dB slopes would be better in a car, unless that choice of slope changes the acoustic response for a better sum with the next driver and filter. 

Just more mythology...Cars are not houses. Car doors are not flat baffles. Listening in an anechoic room is boring.


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## Hanatsu (Nov 9, 2010)

Andy Wehmeyer said:


> And this is the better question ^^
> 
> *The only crossover and the only phase shift we hear (if we hear the pahse shift) is the ACOUSTIC response.* The electrical filters only matter because they shape the acoustic response. The alignment of the electrical filters doesn't mean ANYTHING unless you're simply designing electrical filters.
> 
> ...


That about sums it up ^^


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## 14642 (May 19, 2008)

OK. So I have to issue a caveat here, because what Patrick has posted is completely correct if one is designing speakers. Designing speakers is typically an exercise in designing just the speaker/enclosure/crossover combination. Then and especially for home audio and pro audio, the speaker is placed in a room and some equalization is applied to help correct the room response as it is applied to the speaker. 

This same process CAN be applied to a car, but it's much dicier. We don't really design a speaker/enclosure/crossover combination and then place the well designed speaker in the car. We mount the speaker in the car and the door panel, dashboard, etc is the baffle. We also don't need to correct the speaker and the room separately because everything we hear happens very soon after the initial response of the speakers reaches our ears. We correct the speaker and the room at the same time. 

Patrick and I have different methods for arriving at a similar outcome. He often favors pattern control (eliminating reflections from adjacent boundaries as much as possible). This often requires massive vehicle modification. The 6" waveguide in the picture is, in my opinion, an impractical solution for installing a 20mm tweeter in a car, if time and expense are a concern. For me, time and expense is a concern, so I prefer the spread the chaos around and use an EQ to make as many corrections as possible method. With a center speaker and some signal steering, I find that similar system design can be easily applied across many different cars for a predictable outcome. 

With all of that said, what Patrick has posted here is certainly true and what I've posted here is true too. Both will achieve similar results. Choosing a method is just that--choosing a method and the compromises that go along with the method. 

On a final note, I don't quite understand how shallow slopes minimize comb filtering in a car. Comb filtering is often caused by more than one source playing the same or similar sounds. In a car, lot of reflections cause comb filtering and so do two speakers in different locations if they play the same thing. HOW can maximizing the range where both speakers play decrease comb filtering? Or is this "Spread even more chaos around"?


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## MacLeod (Aug 16, 2009)

What is considered shallow? My Polk SR 6.5's in the doors are cut at 3.2K @ 12 dB and my Scan Illuminators on the dash on axis also cut at 3.2K @ 12 dB and it works very well compared to 24 dB. I've used 24 dB slopes for years cause everybody else did but have found this combination to sound significantly better at least in this car ('12 Accord sedan). I worked with it for weeks tryingto get tthe 24 dB curve to sound as good as the 12db curve but whenever I A/B'd between 12 and 24 dB slopes, 12 was night and day better. Not just in tonality either. Imaging was a little more focused I'm assuming from some phase changes. 

From what I'm getting here, shallow slopes don't work in a car, but my 12 dB slopes are working pretty well. 

So is 12 dB also too shallow and I'm just hearing things wrong? Wouldn't be the first time. 

Sent from my Galaxy Note 2.


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## ErinH (Feb 14, 2007)

Andy Wehmeyer said:


> On a final note, I don't quite understand how shallow slopes minimize comb filtering in a car. Comb filtering is often caused by more than one source playing the same or similar sounds. In a car, lot of reflections cause comb filtering and so do two speakers in different locations if they play the same thing. HOW can maximizing the range where both speakers play decrease comb filtering? Or is this "Spread even more chaos around"?


I'm not sure if this was directed to me, but in case it is....

We've got a misunderstanding somewhere. I'm actually saying what you've said. I don't at all think a shallow slope helps anyone in car audio; not unless the speaker has such a rolloff where a shallow is just an obvious choice... and as much a fan of spreading the chaos as I am, doing so outside the passband of a speaker where it's going to clash with not only the environment but other speakers' response is not my idea of a practical fulfillment of that idea. 

Cliffs: Andy, we agree. Unless I'm on acid and am totally misunderstanding your post.


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## pionkej (Feb 29, 2008)

MacLeod said:


> What is considered shallow? My Polk SR 6.5's in the doors are cut at 3.2K @ 12 dB and my Scan Illuminators on the dash on axis also cut at 3.2K @ 12 dB and it works very well compared to 24 dB. I've used 24 dB slopes for years cause everybody else did but have found this combination to sound significantly better at least in this car ('12 Accord sedan). I worked with it for weeks tryingto get tthe 24 dB curve to sound as good as the 12db curve but whenever I A/B'd between 12 and 24 dB slopes, 12 was night and day better. Not just in tonality either. Imaging was a little more focused I'm assuming from some phase changes.
> 
> From what I'm getting here, shallow slopes don't work in a car, but my 12 dB slopes are working pretty well.
> 
> ...


It's already been said by both Andy and myself, the slope that matters is the ACOUSTIC response. That's a combination of the driver AND filter response. Have you measured either driver at that point? You may every well have 24db slopes using a 12db crossover. 

I'm running:

[email protected]
[email protected] and [email protected]
[email protected] and [email protected]
[email protected]

These electric crossovers gave me ACTUAL crossover points at 65hz, 150hz, and 3150hz...all with LR4 slopes


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## pionkej (Feb 29, 2008)

I also agree with Andy (and Bateman) that having 6db slopes isn't a terrible thing and I even said that in my very first post. It CAN be done and, as you can see above, I'm doing it on one driver myself. 

The thing is, and Bateman is guilty of this, you can't use home/pro audio speakers for justification. Those speakers are part of a SYSTEM that is carefully designed. It is designed without a room to influence it. You take speakers, enclosure, and crossover and work them for perfect response. THEN you put them in a room (which is still a MUCH better environment in a car) and correct what you can with the room. In a car, you put speakers in the best part of the room you can fit them in the best enclosure you can manage and THEN you work on the crossover and EQ together. It's just not apples to apples. 

A poorly executed 6db slope system can kill a driver (or drivers) VERY quickly. The claimed benefit is minimum phase...but that is totally f#cked the minute you choose to use a car as your platform. It's even harder to get phase right when you have lots of room (nearly unavoidable) AND driver (which 6db slopes give more than higher orders) interactions. That was the entire point of this post, that the "dangers" of 6db slopes largely outweigh the unrealistic "benefit" of minimum phase. Can they be executed properly? Absolutely. Can they be executed properly in a car?? Maybe. But that maybe carries a higher likelihood of failure than success in my opinion , and that enough to try and counter the wholesale recommendations people tend to make about them.


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## copperears (Sep 2, 2010)

> A poorly executed 6db slope system can kill a driver (or drivers) VERY quickly. The claimed benefit is minimum phase...but that is totally f#cked the minute you choose to use a car as your platform. It's even harder to get phase right when you have lots of room (nearly unavoidable) AND driver (which 6db slopes give more than higher orders) interactions. That was the entire point of this post, that the "dangers" of 6db slopes largely outweigh the unrealistic "benefit" of minimum phase. Can they be executed properly? Absolutely. Can they be executed properly in a car?? Maybe. But that maybe carries a higher likelihood of failure than success in my opinion , and that enough to try and counter the wholesale recommendations people tend to make about them.


Have you had a chance to hear Soundeasy's Ultimate Equilizer?
Very nice, realistic sound especially on spoken words. They achieve minimum phase digitally. You need a fast computer to run it, and I think it won't be long before someone comes out with something similar for the 12V croud.


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## MacLeod (Aug 16, 2009)

pionkej said:


> It's already been said by both Andy and myself, the slope that matters is the ACOUSTIC response. That's a combination of the driver AND filter response. Have you measured either driver at that point? You may every well have 24db slopes using a 12db crossover.
> 
> I'm running:
> 
> ...


OK maybe that's it. I haven't measured anything. I don't have any measuring equipment so I've just always done it all by ear. 

I think I'm with y'all now. It's not the number showing on your processor that matters, it's the actual COMBINED slope from the processor and the natural roll off of the driver. 

Sent from my Galaxy Note 2 using Tapatalk.


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## Hanatsu (Nov 9, 2010)

The big misconception (in general) is that the electrical and acoustic response is about the same. Many just try a 6dB filter on their headunit and find that it actually sound good, while having no idea how the acoustic response look. I've used 1st order HP filters several times to tame a rising high-end of a driver and then use a cascaded filter lower down in frequency to attenuate the lows. It's already been mentioned before but the problem I have with using 1st order filters is that if you use them on a tweeter as a HPF, they won't attenuate the power enough around driver resonance to prevent either distortion or even damage to the driver (unless you place the HPF really high). Using a 6dB/oct filter as a lowpass on a woofer (which tend to be 6" or larger) will most likely not "work" as intended either, if the driver is even slightly offaxis, beaming will cause the acoustic rolloff to be steeper than 6dB/oct (EVEN of the on-axis response is flat beyond 10kHz). In a home environment these issues might not at all be issues, we generally listen at lower volume at home due to much lower noise floor (road noise) and there's generally no problem aiming the speakers directly towards your sofa either.

Simply placing a inductor or capacitor in series with your driver will most likely not yield a 6dB/oct acoustical rolloff. All drivers are basically bandpass transducers, which have both a high and lowpass function inherited. Once that shallow slope filter hits the edge (either side) of the driver's passband, the natural rolloff of the driver will act like a cascaded filter together with the electrical filter and therefore increase the slope of the rolloff. Achieving a true 6dB/oct filter over a wide range is quite a challenge, more so in a car, the comb caused by reflections and crap will vary quite some from one position to another, you are likely to run into issues trying to integrate the drivers with eachother over a large bandwidth. Two drivers placed even 4" away from eachother will have a different comb pattern. Instead of narrowing it down to a very small area of issues, there is now a large area of issues if you combine two drivers unique power responses and the comb caused by the reflections. 

I had little luck getting first order filters to sound right in the car, to the honest, my install ain't suited for it. I need 4th order slopes to bring out the best from my drivers. I have heard home audio speakers with 1st order filters that sounded extremely good, if the filter itself contributed to that - I don't know.


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## 14642 (May 19, 2008)

There is no such thing as minimum phase (acoustic) unless it's one driver in an anechoic room. Get over it.


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## smgreen20 (Oct 13, 2006)

Shows how my mind has slipped. I thought that the cover point was -3dB, here you state 6,correct? 

The other thing I thought was that for every 6dB the slopes went in 90 degree intervals. 

Thanks for the read. I haven't read it all yet, only so much time on break at work and wanted to comment.


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## minbari (Mar 3, 2011)

smgreen20 said:


> Shows how my mind has slipped. I thought that the cover point was -3dB, here you state 6,correct?


not sure what you mean by "cover point"?


> The other thing I thought was that for every 6dB the slopes went in 90 degree intervals.


that is a common mistake. people are told that a 6db/oct slope is a 90° shift, but it is a 90° total shift between the LPF and the HPF. they are 45° each. if you use a 6db/oct filter on a woofer and a tweeter, then you get 90°. if you use just one or the other, it is only 45°.

as others have said though, I am not sure obsessing over phase shifts in crossovers is a big deal. 90% of the phase change is right at the crossover point. we hear relative phase changes not absolute phase changes.


> Thanks for the read. I haven't read it all yet, only so much time on break at work and wanted to comment.


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## calebkhill (Jan 12, 2013)

This thread is killer.
This is spot on with issues I'm having in my system.

Keep it coming, I've learned tons already.


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## sqnut (Dec 24, 2009)

Picking up from Hans post, let's see how the electronic and acoustic filters work with each other. Let's say a 6.5" mid has a natural roll off of 6 db/oct below 60hz and above 4khz. Your xover points will determine how the two filters work together.

Let's say that you follow the octave above rule and lpf at 120 and hpf at 3khz. Lets say you set the slopes at 12db/oct at both ends. At the lower end you've got a 12db slope from 120-60 hz and an 18db/oct below 60. So as you're moving further away from the xover point the level of attenuation is increasing, which is good. At the top end, you've got 12 db from 3-4khz and 18db beyond 4khz. Here the two filters are cascading.

Now lets look at a 4th order xover at 60 and 3.5khz. Here the electronic and acoustic filters are overlapping and you'll get more or less a 30db slope from the xover points.


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## smgreen20 (Oct 13, 2006)

minbari said:


> not sure what you mean by "cover point"?
> 
> that is a common mistake. people are told that a 6db/oct slope is a 90° shift, but it is a 90° total shift between the LPF and the HPF. they are 45° each. if you use a 6db/oct filter on a woofer and a tweeter, then you get 90°. if you use just one or the other, it is only 45°.
> 
> as others have said though, I am not sure obsessing over phase shifts in crossovers is a big deal. 90% of the phase change is right at the crossover point. we hear relative phase changes not absolute phase changes.


Sorry, that was to say xover point not cover point, interpretive text on my phone thought otherwise.


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## minbari (Mar 3, 2011)

lol, ok. auto-correct to the rescue.


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## 14642 (May 19, 2008)

Guys, the only way to do this correctly is to set the crossovers while viewing the response on some kind of analyzer. Unless you are doing that and adjusting frequency and slope and EQ to achieve your target ACOUSTIC alignment, then there's no reason to be talking about phase shift, alignment or anything else because you're just guessing. 

When you combine EQ with crossover, you change the slopes, the Q and the F3--you change the alignment. When you measure frequency response in the car, it isn't the same as measuring the response of the driver in an anechoic room, which is what all of those beautiful curves in the home audio speaker manuals are. In the car, you measure the sound power response of the speaker along with all of the reflections. Because of this, there's no reason to even talk about phase response because there isn't much you can do about it.


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## thebookfreak58 (Jun 18, 2012)

How does one safely measure the acoustic roll-off of a tweeter?


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## MacLeod (Aug 16, 2009)

thebookfreak58 said:


> How does one safely measure the acoustic roll-off of a tweeter?


Just use a low volume I would think.


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## minbari (Mar 3, 2011)

thebookfreak58 said:


> How does one safely measure the acoustic roll-off of a tweeter?


You use 1 watt sweep and test with something like klippel

sent from my phone using digital farts


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## decibelle (Feb 17, 2011)

Would anyone be opposed to making this thread a sticky, or at least adding it to the "Useful threads" thread? There is a ton of useful information and discussion in here that deserves better than to eventually be washed away into the double-digit pages when all is said and done.


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## thomasluke (Jun 10, 2011)

millerlyte said:


> Would anyone be opposed to making this thread a sticky, or at least adding it to the "Useful threads" thread? There is a ton of useful information and discussion in here that deserves better than to eventually be washed away into the double-digit pages when all is said and done.


I second that. It's right up there with Secrets of Amplifier and Speaker Power Requirements Revealed.


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## ultimatemj (Jan 15, 2009)

I agree with millerlyte, but would propose someone rewrite it as a sticky. 

Maybe titled something like "Crossovers and acoustic response"?


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## calebkhill (Jan 12, 2013)

^^ Agree.


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## pionkej (Feb 29, 2008)

Andy Wehmeyer said:


> Guys, the only way to do this correctly is to set the crossovers while viewing the response on some kind of analyzer. Unless you are doing that and adjusting frequency and slope and EQ to achieve your target ACOUSTIC alignment, then there's no reason to be talking about phase shift, alignment or anything else because you're just guessing.
> 
> When you combine EQ with crossover, you change the slopes, the Q and the F3--you change the alignment. When you measure frequency response in the car, it isn't the same as measuring the response of the driver in an anechoic room, which is what all of those beautiful curves in the home audio speaker manuals are. In the car, you measure the sound power response of the speaker along with all of the reflections. Because of this, there's no reason to even talk about phase response because there isn't much you can do about it.


Andy,

I personally do exactly that, but it's taken me a long time to get there. Mind you I care nothing about " minimum phase", but I have, over many iterations, developed a "target curve" that works for my car (and is similar to the Andy curve). 

I first measure each speaker in the car at low volume unfiltered. I look at roll off and ballpark crossover points. Then I set them and measure again. I target a LR4 acoustic slope. If they are close to target I play music that will stress the bottom (excursion) and top (breakup) end of the speaker. If something falters, I adjust till it's good. These are my limits. Now I focus on really nailing the cutoff. I do this via crossover type and order first and then fine tune with EQ. Now that each driver is dialed into the range inside and outside the passband, driver to driver integration via TA is much easier. Once this is all set, I use a universal EQ to shape system response. Since every driver is now effected, the phase relationship is fixed and I don't have to continually adjust everything because a minor EQ tweak. 

Below is each driver, shaped to my target with LR4 slopes integrated.


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## BuickGN (May 29, 2009)

I also would like to see this made a sticky. I'm sure there are many more like myself that have nothing to contribute but look forward to reading it every day and have read it at least 20 times. Last night I got in the car with this thread on my iPad and started experimenting based on what I've read.


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## Patrick Bateman (Sep 11, 2006)

copperears said:


> Have you had a chance to hear Soundeasy's Ultimate Equilizer?
> Very nice, realistic sound especially on spoken words. They achieve minimum phase digitally. You need a fast computer to run it, and I think it won't be long before someone comes out with something similar for the 12V croud.


It's the spoken word and the imaging of low order slopes that got me hooked.
I sit at home and write software all day, and 75% of the time I'm listening to podcasts, not music. So intelligibility is really important.

Having said that, I think there's a couple 'truths' about low order slopes:

1) Don't bother using them if you can't get the drivers within one wavelength of each other.

2) In a few years all of this will be moot; we'll use software to fix phase. Right now that's bleeding edge technology, but it'll certainly filter down. For instance I'm listening to some TV over my Vandersteens, and I don't need to crank the volume up very high to understand what people are saying. I think a big part of that is due to the intelligibility of tight driver spacing and first order slopes.


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## Neil_J (Mar 2, 2011)

Patrick Bateman said:


> 2) In a few years all of this will be moot; we'll use software to fix phase. Right now that's bleeding edge technology, but it'll certainly filter down.


I assume you're taking about in the future using FIR filters instead of the usual IIR filter with BW or LR coefficients, yes? Those come with a whole bunch of tradeoffs in the audio world. FIR filters get around phase distortion by delaying the output as to not violate causality laws of physics. But by doing that, you get delay times and pre ringing. Everything in the digital filtering world is a tradeoff.


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## ansuser (Dec 18, 2011)

Andy Wehmeyer said:


> And this is the better question ^^
> 
> The only crossover and the only phase shift we hear (if we hear the pahse shift) is the ACOUSTIC response. The electrical filters only matter because they shape the acoustic response. The alignment of the electrical filters doesn't mean ANYTHING unless you're simply designing electrical filters.
> 
> ...


Can I go with a little more practical question after these words, Andy?

I'm working on "MS-8 side effect speakers" that should be better than stock rear door locations (car is Mk6 VW Golf). I figured I can fit Fountek FR88ex fullranges complimented with 3/4" Dayton ND20FA tweeters (which sound OK at 4000 Hz and above). I would like to cross them at 6 kHz (above this point I can hear too much sibilance from Founteks). What filter type would you recomend in this case? Can I use only HP filter for tweeter and rely on MS-8 to equalize the response above X-over point?


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## BuickGN (May 29, 2009)

I would just like to say that my tune is the best it's ever been thanks to this thread. I started over from scratch and focused on the power response first and foremost. I was able to stop the stage from wandering L to R at different frequencies and TA is much easier to set now. The stage also seemed to change slightly with more volume and that has all but disappeared now. Much less change when I turn my head side to side and the sweet spot seems larger. I'm looking forward to getting off work today to continue the tuning, I feel that I'm on the right track with just a little touch up to the EQ to get it right. Just wanted to say thanks. If anyone could see my crossover settings they would probably think I'm crazy.


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## Woosey (Feb 2, 2011)

Andy Wehmeyer said:


> There is no such thing as minimum phase (acoustic) unless it's one driver in an anechoic room. Get over it.


One problem less to worry about....


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## JoshHefnerX (Jun 13, 2008)

I have kind of a tangent I'd like to ask about here - and I may be way off base.... But my understanding of the crossovers and the phase changing is because of the actual hardware - inductors/caps ect. Are the newer generation of computerized dsp's modeling those ideas - or can they simply attenuate the sound - like dropping the volume knob... listening at a lower volume doesn't change the phasing compared to the source.

Josh


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## copperears (Sep 2, 2010)

> > Quote:
> > Originally Posted by Patrick Bateman View Post
> > 2) In a few years all of this will be moot; we'll use software to fix phase. Right now that's bleeding edge technology, but it'll certainly filter down.
> >
> > I assume you're taking about in the future using FIR filters instead of the usual IIR filter with BW or LR coefficients, yes? Those come with a whole bunch of tradeoffs in the audio world. FIR filters get around phase distortion by delaying the output as to not violate causality laws of physics. But by doing that, you get delay times and pre ringing. Everything in the digital filtering world is a tradeoff.



Neil J,

The link below speaks to your concerns above. I agree with the conclusion at the end of the study, in that I can't hear any ringing.


http://www.bodziosoftware.com.au/Pre_Post_Ringing_IR_And_Pulses.pdf


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## Neil_J (Mar 2, 2011)

copperears said:


> Neil J,
> 
> The link below speaks to your concerns above. I agree with the conclusion at the end of the study, in that I can't hear any ringing.
> 
> ...


I get the gist of the paper, but I think the whole thing depends on the EXACT filter that you're listening to at that time... If you're doing simple eq's like in the music production business, then no you won't hear it. If you're correcting for a crazy room to mitigate room issues (which I think was where Patrick was going with his comment; after all, you can do FIR crossovers today but that won't get you linear phase in a car, no way, no how), then yes you may in fact hear it. If you're compressing and uncompressing MP3's, then yea, you definitely hear it (I hear it). Especially if the calculated filter taps are coming out of a computer equation that isn't taking everything into account. Filter design is hard. Anyone that says it's easy (or that it doesn't come with tradeoffs) doesn't understand filter design.

Even if you couldn't hear any ringing, you've still got the huge problem of delay. If you use an FIR filter with a loooooong tap, you will hit play and it will be maybe a second or two later until the music starts. If you're not using a long tap, then you might not be able to do those crazy room corrections that we're talking about, at least not down in the sub-bass region. There are other tricks to get around this, like downsampling the bass and midbass in real-time to get more resolution down in that area, but that creates a whole other set of engineering problems. IIR filters, which are used throughout car audio, do not have any noticeable delay. They come with their own sets of tradeoffs of course. 

Can you implement a crossover with linear phase using a DSP with FIR filters? Sure, you can do that today a MiniDSP MiniSHARC. And maybe it would work and sound OK. Would it sound better than that same setup with IIR butterworth or LR crossovers? IMO the jury is out until several people have listened to it, double-blind, and came to a consensus. I don't know of anyone that's done that in a car audio environment yet (probably some of the guru veteran SQ competetors, but that info's locked in a vault with all their other tricks). I'd love to do that test myself but what I have works good enough today so I probably won't mess with it. I'm still in the camp that phase is one of the last things to tackle, after all the "important" stuff, and I still have "important" stuff to fix in my car like room modes and other stuff.


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## cajunner (Apr 13, 2007)

lots of theory here, and varying amounts of applicable ideas.

my take on this thread surmise, is that I like first order sound. I do.

I like it a lot, I've burned and blown several not-inexpensive drivers doing it, because my sensitive, responsible side that enjoys the intelligibility of 1st order, is rarely in attendance when a jammin' song comes on, and the road is twisty, and I've got the windows down....

and there's the rub. IF you indeed, like reliability, and something as esoteric as full-bandwidth drivers doesn't tickle the pickle, you're not in need of correction.


IF you like it finicky, (especially with conventional driver design) and can hear a difference when you add elements to a crossover, then you're stuck. You have to keep the power down, you have to eat your meat, if you want your pudding.

Hendrix supposedly loved Lowthers. He'd blow 'em up on the regular, because he could afford it and probably because a 2 driver system didn't sound as good to his ears.

And the technology hasn't really changed that.


I will say that I've enjoyed every iteration and implementation basically, in my own vehicles and I opt for the reliability of 12db/oct on the whole, and as a protective measure.


I don't even care that much about the differences in ringing of high order, or the elliptical solutions, or the various acoustic/electric combinations.


I am tired of blowing drivers for the sake of enjoying the music, I'm able to discern the various temperaments and when the time is good I let people turn the volume knob too far, far too regularly.

so, to me, crossover is driver protection first, and the rest is good, I like it, but it's not on that same importance level as finishing a half an album cranked to 11 and driving home WITH tunes still playing.


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## BuickGN (May 29, 2009)

I've tried 6db slopes for a month and my speakers survived just fine. I just didn't like it as much as the steeper slopes. In my opinion there was less intelligibility with shallower slopes even leaving a good sized gap between drivers. Steeper seems less "busy" to me. I currently am running mostly 48db filters and some 36db. It seems so much easier to tune and set TA this way. 

I've got excursion videos on YouTube of my 9" midbasses on a 90hz/6db crossover and it gets up there for a larger midbass. I had some of my midranges running a 400hz/6db crossover and they had more excursion than I thought they were capable of but I think they were on my old phone. That's the other thing I like about the steeper slopes. I have everything crossed over well before beaming yet there's little visible excursion on the midbass, no visible excursion on the midrange so distortion has to be low. My system sounds best with the tweeters taking over at 3khz and when I used 3khz with 6db crossover it made me a little nervous but always sounded good. I guess I really have no point to this lol.


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## cajunner (Apr 13, 2007)

BuickGN said:


> I've tried 6db slopes for a month and my speakers survived just fine. I just didn't like it as much as the steeper slopes. In my opinion there was less intelligibility with shallower slopes even leaving a good sized gap between drivers. Steeper seems less "busy" to me. I currently am running mostly 48db filters and some 36db. It seems so much easier to tune and set TA this way.
> 
> I've got excursion videos on YouTube of my 9" midbasses on a 90hz/6db crossover and it gets up there for a larger midbass. I had some of my midranges running a 400hz/6db crossover and they had more excursion than I thought they were capable of but I think they were on my old phone. That's the other thing I like about the steeper slopes. I have everything crossed over well before beaming yet there's little visible excursion on the midbass, no visible excursion on the midrange so distortion has to be low. My system sounds best with the tweeters taking over at 3khz and when I used 3khz with 6db crossover it made me a little nervous but always sounded good. I guess I really have no point to this lol.



no it makes perfect sense, and there are drivers I can't listen to in 1st order, either there's a spike that isn't being attenuated on the midrange's top end, or the tweeter is harsh with distortion at reasonable volumes down low.

once you've corrected any physical limitation of a driver with the choice of crossover, and you've ruled out reliability or not blowing speakers due to carelessness, then you can move up the acoustic Maslow's pyramid and get to individual taste and bargain with ringing modes or phase distortions, or comb filtering, now I'm lost without a point, lol..

I like to listen loud.

In a car, the drivers stay clean, with steeper slopes at higher power levels.

if you like to listen at average conversational levels, you may not need the protection, or reduction in excursion-induced distortion, you may need to hear more clearly against the background noise. I buy high performance drivers so I can escape the background. It might be a brute force approach, but it's exciting.

If you're one of those golden ears who can tell if your speaker cables are elevated or not, or you can hear the capacitive changes in interconnects, or you swear that rope-lay winding is audible, more power to ya.

if audio wasn't filled with shysters and con men, I wouldn't feel as smart for knowing the difference.


(disclaimer: I know nothing)


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## BuickGN (May 29, 2009)

In my case it wasn't a problem with hitting the speakers limits or audible distortion. I didn't like the sound at low volumes or at high volumes. I was somewhat impressed at how they did cranked up with shallow slopes. Nothing ever got harsh or distorted, it sounded more like a phase issue. It didn't stage that well either. I had no idea the midrange had that kind of excursion ability. I expected them to bottom but they never did. The front stage has no problems handling the full 1200w even with 6db slopes. Maybe I never really put the time and effort in to the tuning to make them sound well. 

The steeper slopes just sound better out of the box in my car with my locations and setting TA is so much easier with steeper slopes. I still have my 6db tune saved, maybe I'll try it over the holidays. For what its worth midbass is in the doors, mids in the kicks, and tweeters on the dash nearly on axis.


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## tonny (Dec 4, 2010)

Neil_J said:


> I get the gist of the paper, but I think the whole thing depends on the EXACT filter that you're listening to at that time... If you're doing simple eq's like in the music production business, then no you won't hear it. If you're correcting for a crazy room to mitigate room issues (which I think was where Patrick was going with his comment; after all, you can do FIR crossovers today but that won't get you linear phase in a car, no way, no how), then yes you may in fact hear it. If you're compressing and uncompressing MP3's, then yea, you definitely hear it (I hear it). Especially if the calculated filter taps are coming out of a computer equation that isn't taking everything into account. Filter design is hard. Anyone that says it's easy (or that it doesn't come with tradeoffs) doesn't understand filter design.
> 
> Even if you couldn't hear any ringing, you've still got the huge problem of delay. If you use an FIR filter with a loooooong tap, you will hit play and it will be maybe a second or two later until the music starts. If you're not using a long tap, then you might not be able to do those crazy room corrections that we're talking about, at least not down in the sub-bass region. There are other tricks to get around this, like downsampling the bass and midbass in real-time to get more resolution down in that area, but that creates a whole other set of engineering problems. IIR filters, which are used throughout car audio, do not have any noticeable delay. They come with their own sets of tradeoffs of course.
> 
> Can you implement a crossover with linear phase using a DSP with FIR filters? Sure, you can do that today a MiniDSP MiniSHARC. And maybe it would work and sound OK. Would it sound better than that same setup with IIR butterworth or LR crossovers? IMO the jury is out until several people have listened to it, double-blind, and came to a consensus. I don't know of anyone that's done that in a car audio environment yet (probably some of the guru veteran SQ competetors, but that info's locked in a vault with all their other tricks). I'd love to do that test myself but what I have works good enough today so I probably won't mess with it. I'm still in the camp that phase is one of the last things to tackle, after all the "important" stuff, and I still have "important" stuff to fix in my car like room modes and other stuff.


I've tested with that last year in a car with the new odr dsp which has iir and fir filters, I did set up the car 2 time's one time with the normal filters and one time with the fir filters, with the same frequentie response and so on and then listened to both settings. For us the normal filters sounded better than the Fir filters, the system was just more alive and sounded more real.


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## 14642 (May 19, 2008)

Neil_J said:


> I get the gist of the paper, but I think the whole thing depends on the EXACT filter that you're listening to at that time... If you're doing simple eq's like in the music production business, then no you won't hear it. If you're correcting for a crazy room to mitigate room issues (which I think was where Patrick was going with his comment; after all, you can do FIR crossovers today but that won't get you linear phase in a car, no way, no how), then yes you may in fact hear it. If you're compressing and uncompressing MP3's, then yea, you definitely hear it (I hear it). Especially if the calculated filter taps are coming out of a computer equation that isn't taking everything into account. Filter design is hard. Anyone that says it's easy (or that it doesn't come with tradeoffs) doesn't understand filter design.
> 
> Even if you couldn't hear any ringing, you've still got the huge problem of delay. If you use an FIR filter with a loooooong tap, you will hit play and it will be maybe a second or two later until the music starts. If you're not using a long tap, then you might not be able to do those crazy room corrections that we're talking about, at least not down in the sub-bass region. There are other tricks to get around this, like downsampling the bass and midbass in real-time to get more resolution down in that area, but that creates a whole other set of engineering problems. IIR filters, which are used throughout car audio, do not have any noticeable delay. They come with their own sets of tradeoffs of course.
> 
> Can you implement a crossover with linear phase using a DSP with FIR filters? Sure, you can do that today a MiniDSP MiniSHARC. And maybe it would work and sound OK. Would it sound better than that same setup with IIR butterworth or LR crossovers? IMO the jury is out until several people have listened to it, double-blind, and came to a consensus. I don't know of anyone that's done that in a car audio environment yet (probably some of the guru veteran SQ competetors, but that info's locked in a vault with all their other tricks). I'd love to do that test myself but what I have works good enough today so I probably won't mess with it. I'm still in the camp that phase is one of the last things to tackle, after all the "important" stuff, and I still have "important" stuff to fix in my car like room modes and other stuff.


No, i think most of the heavy hitter competitors are busy with a Thesaurs trying to figure out how to claim that kick panel speakers and a single subwoofer could possibly get a third creativity point. I think they get one for completely rebuilding the dashboard for "symmetry" and another one for using tamper-proof Torx screws to mount the speakers.


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## ErinH (Feb 14, 2007)

^ a LOT has changed since you went to a show, then. Because, my car does nothing to fit those standards at all. 

there's an install class. and I stay far away from that class, Andy. As do most of my friends with little fab skill... or for that matter, ingenuity. LOL.

*as an aside, it's too bad that install points are given for the scientific reasons you chose to do something as opposed to the look and detail of something, so I smell what you're cookin there. *


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## MacLeod (Aug 16, 2009)

Andy Wehmeyer said:


> No, i think most of the heavy hitter competitors are busy with a Thesaurs trying to figure out how to claim that kick panel speakers and a single subwoofer could possibly get a third creativity point. I think they get one for completely rebuilding the dashboard for "symmetry" and another one for using tamper-proof Torx screws to mount the speakers.


LOL! Yeah that's not how MECA works (don't know about IASCA lately). In MECA, your score is SQ only and install isn't even looked at. It's the only way I can compete cause while I'm a pretty good tuner, I have zero fabrication or install skills. If it weren't for PVC end caps, my tweeters would be super glued to the pillars.......but I could always claim they were "chemically bonded". Ain't that right Foam?


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## pocket5s (Jan 6, 2012)

MacLeod said:


> LOL! Yeah that's not how MECA works (don't know about IASCA lately). In MECA, your score is SQ only and install isn't even looked at. It's the only way I can compete cause while I'm a pretty good tuner, I have zero fabrication or install skills. If it weren't for PVC end caps, my tweeters would be super glued to the pillars.......but I could always claim they were "chemically bonded". Ain't that right Foam?


Until you get to the expert classes iasca is the same. The new usac classes have sound and sound plus install as well.


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## 14642 (May 19, 2008)

Yeah, I'm familiar with all of the rules and two of the organizations. I think it should be 1000 points for "does it sound great?", 25 points for "does it look cool" and 100 points for "is it safe?". Finally, I think the car should have to be drivable in order to compete. This moving the seats back so only Shaquille O'Neill can drive it is complete ********.


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## 14642 (May 19, 2008)

Oh...and I think one-seat judging should only be for novice class.


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## Neil_J (Mar 2, 2011)

Andy Wehmeyer said:


> Oh...and I think one-seat judging should only be for novice class.


Well I was with you until right there


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## Niebur3 (Jul 11, 2008)

2 seat judging with not being able to move your seats back?? Sounds like you would need a center channel, Andy!


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## Mic10is (Aug 20, 2007)

Andy Wehmeyer said:


> Oh...and I think one-seat judging should only be for novice class.


^^^ What he said^^^


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## Patrick Bateman (Sep 11, 2006)

BuickGN said:


> I would just like to say that my tune is the best it's ever been thanks to this thread. I started over from scratch and focused on the power response first and foremost. I was able to stop the stage from wandering L to R at different frequencies and TA is much easier to set now. The stage also seemed to change slightly with more volume and that has all but disappeared now. Much less change when I turn my head side to side and the sweet spot seems larger. I'm looking forward to getting off work today to continue the tuning, I feel that I'm on the right track with just a little touch up to the EQ to get it right. Just wanted to say thanks. If anyone could see my crossover settings they would probably think I'm crazy.


Over at Stereophile there's an independent review of a speaker named 'The JBL Synthesis Array" or something like that. In the review, they measured the power response, and it was shockingly flat. Interesting stuff; clearly JBL is optimizing their speakers for the power response, not the on-axis response.


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## MacLeod (Aug 16, 2009)

Andy Wehmeyer said:


> Oh...and I think one-seat judging should only be for novice class.


Glad you're not in charge then. 

That would eliminate about 75% of the cars/competitors out there including me. Most guys can't afford a spare car just for competition and don't want to cut holes in the floors and/or give up half their legroom or rip out and rebuild their entire dash for a car stereo. My car is also the car we get groceries in, haul my little boy around in and take trips in. I get why you want that but that's not practical in this day and age when nobody is sponsored anymore and we're all doing it on our own dime and it is expensive as ****! I agree with you that a great 2 seat car is the ideal and should be the ultimate goal but for most competitors, it ain't worth it. This is just car stereo we're talking about, not curing cancer. I'm in it for the competition and to finally win a championship and not necessarily the pursuit of perfect audio. If that's what I was after, I'd be a home audio nut. 

That said, I do think 2 seat classes could be expanded more and I do think there should be a place for 2 seat competition, but it shouldn't be made at the expense of 1 seat judging which is more practical nowadays and opens up competition to a lot more people. 

Sent from my Galaxy Note 2.


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## Neil_J (Mar 2, 2011)

MacLeod said:


> Glad you're not in charge then.
> 
> That would eliminate about 75% of the cars/competitors out there including me. Most guys can't afford a spare car just for competition and don't want to cut holes in the floors and/or give up half their legroom or rip out and rebuild their entire dash for a car stereo. My car is also the car we get groceries in, haul my little boy around in and take trips in. I get why you want that but that's not practical in this day and age when nobody is sponsored anymore and we're all doing it on our own dime and it is expensive as ****! I agree with you that a great 2 seat car is the ideal and should be the ultimate goal but for most competitors, it ain't worth it. This is just car stereo we're talking about, not curing cancer. I'm in it for the competition and to finally win a championship and not necessarily the pursuit of perfect audio. If that's what I was after, I'd be a home audio nut.
> 
> ...


Very well said. To add, and I speak from personal experience here as I used to run a full surround system with a center channel -- I really don't think that having a single "sweet spot" at the driver's ears is a bad compromise. Quite the opposite really. My imaging in the drivers seat improved when I got rid if the center channel and surround upmixing. And my car was 30 pounds lighter after removing the speakers and amps. My passengers couldn't care less as long as I have sound playing. And if they want to hear it, they can jump in the drivers seat.

But I do agree that putting the seat all the way back (and reclined) is a little ridiculous.


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## Mic10is (Aug 20, 2007)

MacLeod said:


> Glad you're not in charge then.
> 
> That would eliminate about 75% of the cars/competitors out there including me. Most guys can't afford a spare car just for competition and don't want to cut holes in the floors and/or give up half their legroom or rip out and rebuild their entire dash for a car stereo. My car is also the car we get groceries in, haul my little boy around in and take trips in. I get why you want that but that's not practical in this day and age when nobody is sponsored anymore and we're all doing it on our own dime and it is expensive as ****! I agree with you that a great 2 seat car is the ideal and should be the ultimate goal but for most competitors, it ain't worth it. This is just car stereo we're talking about, not curing cancer. I'm in it for the competition and to finally win a championship and not necessarily the pursuit of perfect audio. If that's what I was after, I'd be a home audio nut.
> 
> ...



As you know, at one time, all SQ competition was 2 seat. and just like now, the vast majority of competitors were not sponsored and did not have dedicated competition vehicles.
Just like today, the majority competed with daily drivers, who had families, and had the same duties, responsibilities and requirements that went along with having a family.
Yet, these people managed to compete at pretty high levels with more requirements in comparison to today's competitors.

Cost comparison, it is cheaper overall now to buy equipment than it was in the 90s and you certainly get much more and require less equipment than previously.
Now you can buy an all in one DSP which gives you time alignment which really didnt exist in car audio during the prevalence of 2 seat judging, you also get 1/3octave or more EQ plus XO with almost infinitely variable frequencies and slopes.
Whereas before, you had to buy a separate stereo 1/3octave EQ or buy 2 EQs to do L/R, plus a Separate XO. Most also purchased a 3rd EQ for RTA.
Amps by comparison were more expensive for less wattage. Most Subs still required fairly large enclosures....

Yet again, these people with the same basic limitations of today's competitors managed to competed successfully on a National Scale with required 2 seat judging.


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## 14642 (May 19, 2008)

I don't think there's anything wrong with building one seat cars, but I don't think a good one seat car makes you a world champion. It's just too easy.


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## pionkej (Feb 29, 2008)

Since we've stepped into the 1-seat vs 2-seat realm, I'm going to voice an opinion here.

First, to Mic's reply about then vs now. I don't know about then, as I wasn't there to compete/listen. But I can tell you that today, 99.2% of the people take one of two strategies for 2-seat. The first camp, sets staging for the drivers seat and makes tonality good/great for both seats. This isn't that far of a step from setting up a single seat car in my opinion and still using DSP, it just takes a bit more placement work on the front end and you can get great 1-seat and good 2-seat. The other camp compromises both seats for both staging and tonality and being "good" overall. Even with DSP making tuning more accessable to the "normal" guy, I'd say what we hear today (from the competitors that choose 2-seat) isn't that different than the "old school" stuff. If anything, I'd say it's better, though likely less impressive since it IS easier.

The only exception I've heard to any of this is Mark Eldridge's car. It sounds great from either seat, which leads me to Andy's comment:



> I don't think there's anything wrong with building one seat cars, but I don't think a good one seat car makes you a world champion. It's just too easy.


Mark is a perennial winner in SQ. He is because his car sounds great in both seats and in my opinion deserves the accolades.

However, I don't think one person having a great car in 2-seat or lots of people having good cars in 1-seat means there is no ability to be a "world champion" by doing 1-seat only. The thing is, it's easier to differeniate the wheat from the chaff (as they say) in 2-seat. Right now I believe there is a large margain between good and great. In 1-seat, the line is much closer and harder to distinguish. However, it is still VERY difficult to achieve "greatness" in 1-seat and I think there is a significant accomplishment in doing so. And for my end, I do still end up with staging+tonality in the DS and tonality in the PS with my install.


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## MacLeod (Aug 16, 2009)

Andy Wehmeyer said:


> I don't think there's anything wrong with building one seat cars, but I don't think a good one seat car makes you a world champion.


That is the most ridiculous thing I've ever heard! That's like saying winning the World Series doesn't make you a world champion because you didn't win the Stanley Cup. It's 2 different formats. 

Please tell me you're not one of these guys that think current generation competitors aren't "real champions" because they have processors and 1 seat systems and all you last gen guys are the true car audio competitors. It is EXTREMELY difficult to win a championship regardless whether it's 1 seat or 2 seat. Trust me dude, I know only too well. I'm 0 for 5 at finals. 1 seat isn't any easier or harder, it's just a different format. I'm sorry if the vast majority of competitors are 1 seat guys now but to look down your nose at them and belittle their accomplishments is complete horseshit! 

And let's not act like 2 seat is God's own sound. Every 2 seater I've heard sounds good from both seats but not great from either. I'd rather have a 1 seat car that sounds great from my seat and who cares if the center image is all the way right from my wife's seat. 

By the way, that's how one of my buddies won a WORLD CHAMPIONSHIP in MECA's 2 seat class with his 1 seat car, by scoring a 90-something in the left seat and a 70-something in the right. Beat all the 2 seat cars scoring 70's from both seats. 



Mic10is said:


> As you know, at one time, all SQ competition was 2 seat.....


Yep, and it just about went extinct. 

Look, I get what y'all are on about, cars that sound good from both seats are cool as ****. No doubt there at all. But so are 1 seat cars like Steve Cook's that sound like a home audio system. And I will reject to my dying breath that there is something "wrong" with 1 seat or that 1 seat competitors and definitely 1 seat champions are somehow not as good as the last generation. 

Mark E is the only one who I'll take that **** from cause he's still in the lanes whooping ass. It's the ones that are just sitting on the sidelines looking down their noses at the rest of us telling us we're not "real champions" that I have no respect for. Hopefully Andy I'm totally misunderstanding you because I've been reading and learning from you for about a decade now. 


Sent from my Galaxy Note 2.


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## Neil_J (Mar 2, 2011)

Andy Wehmeyer said:


> I don't think there's anything wrong with building one seat cars, but I don't think a good one seat car makes you a world champion. It's just too easy.


I was going to type up a long retort, but that would be too easy 

I think arguing over 1-seat or 2-seat is like arguing over which religion or philosophy is best. I'm a progressive in that context, so I say give people the freedom to do either/or and see how both fair. They kinda do that now and it's one of the few things I don't currently have a beef about in the meca / iasca rules.


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## MacLeod (Aug 16, 2009)

I don't think either are "best". They're 2 different formats in a sport I enjoy. It's that simple. I'm not interested in SPL but that doesn't mean there is anything wrong with it or I don't have mad respect for the hard work that goes into it. There are lots of paths in car audio. 

Sent from my Galaxy Note 2.


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## Hanatsu (Nov 9, 2010)

Start a new thread if you gonna argue about 1 vs 2 seat installs, this is kinda OT now...


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## Bama-Boy (Nov 17, 2013)

If I'm running a system with an active crossover and I have both left and right channels running with 24db/octave slopes, would a program such as REW show if the two channels are acoustically in phase? 

If it showed that my left was 45° out of phase from my right, would changing one channel to 18db/octave fix it?

Would switching the phase on the channel from 0° to 180° and changing it to 18db/octave have a net effect of 225°?

Would adding delay change the whole thing?


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## ErinH (Feb 14, 2007)

Bama-Boy said:


> If I'm running a system with an active crossover and I have both left and right channels running with 24db/octave slopes, would a program such as REW show if the two channels are acoustically in phase?
> 
> If it showed that my left was 45° out of phase from my right, would changing one channel to 18db/octave fix it?
> 
> ...




Yes to all. 

As Andy has mentioned a few times already, what we need to be concerned with is the final response. And, luckily, any RTA can measure this. Within the RTA you can see things out of phase but you have to compare them to something. What do you compare it to? Another setting, such as a polarity flip on a crossover change. 

When you have two frequencies in phase you have more SPL. So, all you're looking for is to see if the output increases at the region you're adjusting.

This is from my build log:



bikinpunk said:


> random info...
> 
> often it's said that ILD & ITD dictate that phase doesn't matter for high frequencies. It's a notion people have inferred from light reading... and it's not entirely correct. The truth is, time alignment absolutely affects high frequency response. Now, the result isn't as dramatic as it is with midrange frequencies where you can hear the center move left and right with little adjustment between left/right t/a values. However, the time alignment allows a cohesiveness that you can't get simply by adjusting polarity of tweeters. I've often noticed in my car that cycling through T/A 3 times (roughly equivalent to 0.06ms, in 0.02ms steps) results in a full 'phase cycle'. Listen for the "s" sound ... aka: sibilance. Cycle through your T/A and listen for that sound to move out of phase and then *pop* back in phase. You may find the center moves a bit to the right or left, depending on what channel you're adjusting. But this is pretty minor unless you have your tweeters crossed really low. What you'll likely find is that you get in a cycle like I've mentioned where you can literally hear the tweeters pop in phase. Try it. Seriously. You'll notice it. Just shut everything off and leave your tweeters on.
> 
> To illustrate what I've said, here's a comparison of the tweeters in proper polarity; adjusting the left tweeter so it arrives at the same time the right does. The red is with no time alignment. The orange is with time alignment done by ear. See how the red is about 2dB lower than the orange? The orange is in phase and time delayed to match the wavefront of the right side tweeter.


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## Bama-Boy (Nov 17, 2013)

bikinpunk said:


> Yes to all.
> 
> As Andy has mentioned a few times already, what we need to be concerned with is the final response. And, luckily, any RTA can measure this. Within the RTA you can see things out of phase but you have to compare them to something. What do you compare it to? Another setting, such as a polarity flip on a crossover change.
> 
> ...


Thanks for the reply, I was just trying to figure the best way to get there.


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## 14642 (May 19, 2008)

Wow...sorry to offend all you one seat guys. I'm certainly not an old-schooler and I competed with a mountain of DSP when the only DSP available was Pioneer ODR or some converted DriveRack thing. I also built a CES car at JBL like 15 years ago that used a converted DSC260 JBL processor. It was a one seat car. 

I guess what I'm getting at is that I hear too often, "I'm not compromising one seat to get better sound in both." I see that as a cop-out--fox and grapes. 

I'm not a hobbyist. I design and make this stuff and I'd like to see an industry that builds systems that can be shareed with unsuspecting passengers who just might catch the car audio bug as a result of riding in one of these cars. The reality is that optimizing one seat using TA completely destroys the other seat. The best one can hope for in the passenger's seat of one of those cars is the ability to hear both sides but NO stable center image is possible. 

So, maybe you guys will allow me to restate my suggestion. One seat isn't a worthless endeavor, but I think that 2-seat is much more valuable. I'd like to see ALL-SEAT. My Volvo used to do this. Both seats were great and the back seats were too.


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## MacLeod (Aug 16, 2009)

Andy Wehmeyer said:


> I guess what I'm getting at is that I hear too often, "I'm not compromising one seat to get better sound in both." I see that as a cop-out--fox and grapes.
> 
> I'm not a hobbyist. I design and make this stuff and I'd like to see an industry that builds systems that can be shareed with unsuspecting passengers who just might catch the car audio bug as a result of riding in one of these cars. The reality is that optimizing one seat using TA completely destroys the other seat. The best one can hope for in the passenger's seat of one of those cars is the ability to hear both sides but NO stable center image is possible.
> 
> So, maybe you guys will allow me to restate my suggestion. One seat isn't a worthless endeavor, but I think that 2-seat is much more valuable. I'd like to see ALL-SEAT. My Volvo used to do this. Both seats were great and the back seats were too.


I hear ya man and I do agree with you. Having a car sound great from EITHER seat is the ideal way to go and should be the ultimate goal. The only thing that gets my knickers in a twist is the idea that 1 seat competition is somehow easier than 2 seat and "those guys" arent real competitors or champions. Aside from that sentiment, Im 100% with ya. 

I can see where youre coming from too. You see people mounting their mids in pods hanging off the A pillars right next to the windshield even though thats not the best way to do it scientifically but it works well for 1 seat judging at the expense of the passenger seat. Then people go on forums like these and see all the pillar mounted mids and think thats gotta be the way to do it and the notion of proper speaker mounting and locations start to fall by the wayside. So more and more people are getting away from the sound, tried and true methods of speaker mounting and placement.


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## Niebur3 (Jul 11, 2008)

MacLeod said:


> I hear ya man and I do agree with you. Having a car sound great from EITHER seat is the ideal way to go and should be the ultimate goal. The only thing that gets my knickers in a twist is the idea that 1 seat competition is somehow easier than 2 seat and "those guys" arent real competitors or champions. Aside from that sentiment, Im 100% with ya.


1-Seat is easier than 2-seat. It just is. Anyone thinking otherwise is just fooling themselves. That is why there are so few (Mark Eldridge being one) that have successfully accomplished it. Now, to me, winners are winners. So, yes, 1-seat winners are champions as well. I'm not saying a properly set up 1-seat cars is childs-play be any means, but 2-seat is a freakin nightmare to pull off.


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## onebadmonte (Sep 4, 2008)

Sub'd for later reading. Interesting stuff here.


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## MacLeod (Aug 16, 2009)

Niebur3 said:


> 1-Seat is easier than 2-seat. It just is. Anyone thinking otherwise is just fooling themselves. That is why there are so few (Mark Eldridge being one) that have successfully accomplished it. Now, to me, winners are winners. So, yes, 1-seat winners are champions as well. I'm not saying a properly set up 1-seat cars is childs-play be any means, but 2-seat is a freakin nightmare to pull off.


Yeah whatever. I'm not trying to get into a troll fest about which is easier/harder/cooler/sexier. I'm saying they're both equally hard and are both equally worthy of respect at the competition level. I believe that about all aspects of car audio. The SPL guys work their balls off as much as we do as do the install junkies. Winning at the national level is EXTREMELY hard whether it's 2 or 1 seat. 

Sent from my Galaxy Note 2.


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## ultimatemj (Jan 15, 2009)

Equally hard??? Come on man oke:

Sending a man into orbit around the earth is hard...1 seat
Sending a man to the moon and back is harder...2 seat
Sending a man to Mars is...um really F'n hard...all seats


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## BuickGN (May 29, 2009)

This thread has taken a turn for the worst and this is the single most helpful thread I've read. My 02 and I'm done off topic. As Jerry said 1 seat is easier than 2 seat. I'm sure 1 seat is easy to make sound great by the pros. However, with today's stiff competition it's still very hard to place well in 1 seat so in that way 1 seat is not easier. I think 2 seat is not something everyone can do and even fewer are decent at. When the stiff competition is factored in, I don't think 1 seat COMPETITION is easier than 2 seat even though 1 seat is easier to make sound good. 

In my opinion, I'm the only one that matters and the only one in my car 99% of the time. If I could I would tune for 2 seat for the rare time I have a passenger but 1. I struggle to get 1 seat halfway right and 2. Most passengers just want to feel the bass and only care about the pair of 15s in the trunk. Most are disappointed at first when they hear for the first time a system that's level matched and even bass heavy by SQ standards. Most appreciate that it's really clean at high volumes but that's as far as most SQ appreciation goes. Then again most do not sit on the drivers side. 

Sure, it would be fun to try and make both sides sound good at the same time but I have to remember that the point of all of this time and money is to enjoy the music and have it sound great at concert levels. I know my limitations and I don't have the knowledge or the skills to make 2 seats sound good and if I attempt going for 2 seat sound, it would most definitely not sound as good as it does now from my seat.


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## 14642 (May 19, 2008)

bikinpunk said:


> Yes to all.
> 
> As Andy has mentioned a few times already, what we need to be concerned with is the final response. And, luckily, any RTA can measure this. Within the RTA you can see things out of phase but you have to compare them to something. What do you compare it to? Another setting, such as a polarity flip on a crossover change.
> 
> ...


This isn't about localizing sound in the horizontal plane, it's about the magnitude sum of the output of both tweeters. I'm splitting hairs here because the graph will look different if you use this method if you try this with midrange speakers. If you do this in an anechoic room with a pair of mids, there will be a point at which the comb disappears. In a reflective environment, it won't be nearly so obvious.


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## 14642 (May 19, 2008)

My perspective about one seat vs. two seats is NOT the perspective of a competitor. It's from the perspective of someone who provides product and is a stakeholder in the advancement of the industry.

From an aftermarket professional's perspective, it's important that the aftermarket keeps up with trends that regular customers believe are valuable. Surround sound i one of those trends. In a car it can be VERY beneficial, so long as the system is designed and tuned properly. I'd just like the competition organizations to recognize that and incentivize progress that is attractive to a wider audience. This disconnect is one of the reasons that the number of competitors in the lanes has dwindled dramatically over the 25 years I've been involved. You can't be "the standard by which performance is judged" if you don't address it.

Well, that and the music. I don't know anyone who isn't an audiophile who would subject their car to being judged with tracks they find completely irrelevant.


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## Bama-Boy (Nov 17, 2013)

So, if I compete, I'll just have the judges sit in the back seat


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## Regus (Feb 1, 2011)

Anybody mind if I start a new thread on one seat versus two seat and let this one get back to the original topic? It's of interest to me, but if there's nothing more to say I'm happy to leave it for the time being...


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