# Compression Driver Discussion



## lsm

There are a lot of topics here referring to the various body styles & brands of horns but nothing dedicated to the drivers themselves. Im hoping this topic will help shake out some of the pros & cons of the various compression drivers.
Obviously manufacturers have to balance lots of variables when choosing to market a product... With that said is there an "end all be all" driver

I have a few questions to start things off. 

What are the differences between the various dome materials used? 
How do the vintage drivers compare to modern designs? Altec for example...


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## TheScottishBear

I'm taking an early seat at the table. Looking forward to hearing the responses. I have thought about upgrading my selenium 2500ti's down the road. Would like to know what people would recommend.


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## chevbowtie22

I'd like to hear some thoughts too. I'm more than happy with ID CD1Pros BUT I'm always up for trying new drivers.


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## edzyy

chevbowtie22 said:


> I'd like to hear some thoughts too. I'm more than happy with ID CD1Pros BUT I'm always up for trying new drivers.


x2

Pretty happy with my de500's

Was thinking of stepping up to the JBL stuff


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## TheScottishBear

JBL Professional 1" High Frequency Compression Driver Model 2426J Titanium Horn | eBay
They are not the H's but I thought about getting a pair. They are 450 a piece on PE's website. They come up all the time.


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## fenis

I have Beyma CD10Nd's and they have a special polymer diaphragm - they sound very smooth and detailed and also play lower then any of the other 1inch exit drivers i could find.


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## Eric Stevens

The be all to end all driver is the TAD TD2001 and there is a TAD TD2002 not sure if equal or better thn the 2001 though.

There are a lot factors that affect compression driver performance, and what helps it perform better in one area can hurt its performance in another.

I will try and write as much as I can about the parts of the drivers and how they affect performance along with any possible material differences. Of coarse this will be within confines of my knowledge and experience.

Eric


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## edzyy

1500 per driver

...****.


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## edouble101

edzyy said:


> 1500 per driver
> 
> ...****.


These are made by Pioneer. And they are the cheap ones...


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## Mic10is

edouble101 said:


> These are made by Pioneer. And they are the cheap ones...


and the size of a coffee can a very heavy coffee can, like a 16lb coffee can....image trying to support that on the backside of a horn


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## edouble101

I have been wanting to know if there is a significant (audible) advantage of replacing the Ultra compression driver that is currently sold with ESAudio horns? From my understanding it is the horn body that dictates low and high frequency roll-off. So what benefits would there be from a more dynamic compression driver compared to the stock Ultra driver?


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## cajunner

the first horns I ever heard were ID full bodies on TAD 2001 drivers, in a camaro that had a pair of PPI Pro 12's in the back hatch.

it was snazzy.


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## subwoofery

edouble101 said:


> I have been wanting to know if there is a significant (audible) advantage of replacing the Ultra compression driver that is currently sold with ESAudio horns? From my understanding it is the horn body that dictates low and high frequency roll-off. So what benefits would there be from a more dynamic compression driver compared to the stock Ultra driver?


Driver+horn dictate how low it can play 
Driver dictates high frequency roll-off 

A driver that can play really low won't be playing much past 12kHz for eg. 

Kelvin


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## Patrick Bateman

When you're picking a conventional tweeter it generally boils down to a short list of features. Picking a compression driver is similar, but there are a few additional parameters.

For a conventional tweeter, here's a few of the important parameters:

1) *frequency response*
When you have two tweeters that are mismatched, that will significantly screw up your imaging, because your left and right driver must match to create a believable soundstage. In addition, dips and peaks in the frequency response are particularly noticeable in the range of 1khz-4khz.

2) *output*
Due to the small size of a tweeter diaphragm, it can be challenging to generate a lot of output. Note that this is independent of sensitivity; in other words a high sensitivity tweeter can have limited output if it's displacement is low. And a low sensitivity tweeter can have lots of output if it's displacement is high.

3) *cumulative spectral delay*
Resonances in the tweeter can affect it's CSD. For instance, if the dome is heavy it will 'ring' and this 'ringing' will show up in the CSD

















^^^ the measurement above shows the CSD of two similar tweeters that vary in size. The Vifa XT19 at the top has a 3/4" diaphragm, while the XT25 below it has a 1" diaphragm.

4) *distortion*
Lowering harmonic distortion can change the sound of a driver. What's interesting is that this change isn't always beneficial; this is outside the scope of this forum post, but it's definitely a topic that's worth researching. Oddly enough, many people prefer the sound of high distortion to low distortion.

There's probably other factors that I'm too lazy to type up. (Directivity comes to mind.)

In summary, *the ideal tweeter would have flat response, you'd have a second tweeter that matched perfectly, output would be unlimited, and the CSD would decay perfectly. Distortion is audible, but whether it's important is beyond the scope of this discussion.*

Next up - the factors in a compression driver.


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## Diezel10

Mic10is said:


> and the size of a coffee can a very heavy coffee can, like a 16lb coffee can....image trying to support that on the backside of a horn



I built a special aluminum flange that becomes part of the base where the horn bolts up leaving a "tab or ear" with a perforation for further support if I am making sense., Eric I took apart the TAD2001 but from what I can tell its a beryllium diaphragm?


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## Patrick Bateman

_I forgot to mention in my last post - the measurements were taken from speakerdesign.net. The measurements in this post were taken from Augerpro's drivervault._

As mentioned in my last post, four important features of a tweeter are frequency response, output, CSD, and distortion. These parameters are important in a compression driver, but they behave differently.









1) *Frequency response*
The frequency response of a compression driver and a horn is rarely flat. This can be a bit startling to people accustomed to domes. For instance, there are $20 dome tweeters that measure flat on-axis, but there are very very few compression drivers that can do the same thing. 

There are a couple of ways to address this. The most obvious way is electronically; basically use an EQ to take the response and 'flatten it out.'
The other way is to physically do that. To do it physically, you use a horn profile that has a narrower profile at the throat than at the mouth.









In the picture above, the horn profile with the narrowest angle at the throat will generally have flatter on-axis response than the one with the widest angle at the throat. IE, a tractrix horn measures flatter on axis than a conical horn.

In summary - we have a couple ways to flatten the response of a compression driver. Electronically and physically.

So what are the pros and cons of each?

The primary drawback to a profile like tractrix or exponential is that the directivity will vary with frequency. For instance, if you're listening 45 degrees off axis, the response will be dramatically different than if you're listening ON axis.

Whether you consider this a defect or a feature really depends on how you design the entire system. I personally prefer to listen off-axis, and due to that, I generally use waveguide profiles that are conical or close to it.


That scratches the surface on compression driver frequency response, but there's a pile of other factors. Particularly the size, weight and diameter of the diaphragm.


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## Eric Stevens

Diezel10 said:


> I built a special aluminum flange that becomes part of the base where the horn bolts up leaving a "tab or ear" with a perforation for further support if I am making sense., Eric I took apart the TAD2001 but from what I can tell its a beryllium diaphragm?


Yes the TAD2001 has a Beryllium diaphragm. It is made via vapor deposition to a copper form and then the copper is etched away leaving the beryllium dome. It has a larger than normal voice coil and diaphragm that is 2" rather than 1.75" and it has a four slit phase plug rather than the normal 2 or three slit. 

Eric


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## lsm

Bringing this topic back up to see if we can get it going again...


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## Broshi

lsm said:


> Bringing this topic back up to see if we can get it going again...


Thanks for doing this actually. I've been eyeing the DE500s, but it'll be the last thing I ever purchase for the audio side of my build because I just can't justify swapping out drivers. The Pros that I am using are absolutely mint. I would be very interested to hear a detailed review from Eric on the TAD TD2001s though. If anything, one day I'll just jump the gun on those simply to try.


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## thehatedguy

I think the DE500s and D2500s are a step up from the DE200s used in the CD1 Pros IMO, better midrange. There are a lot of new drivers on the market that I haven't played with that look to be really nice. A lot of the "ultimate" driver depends on how low/high you want them to play, the physical size you are limited to, and your budget. If you are using minihorns then that would limit how low you would want/need the drivers to play.

But there are some like Dr. Geddes and Tom Danley who say compression drivers for the most part are commodity items and after EQ there is minimal difference in their performance. I can see where they are coming from, but still don't know if I buy into that line of thought 100% yet.


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## thehatedguy

I might would look at the DE120 and DE400 from B&C over the DE500s. You can get those in a mylar or a titanium diaphragm, pretty smooth response, about the same low end, and cheaper. Never heard either one though. But I generally like mylar/plastics and aluminum over titanium domes though the D2500 and DE500s sound really good.

Some things to look at and to keep in mind though...given you have two drivers that are pretty much the same, the driver with the higher Bl will generally have the better treble response due to having more motor to drive the air load in the horn. Look at the BMS drivers, the 4550 and the 4552- the 4552 is neo and has more motor and has better treble...same goes for all of the Radian drivers- they are all pretty much the same driver except you get more motor as you move up the model range, and the treble gets better.

Master Eric taught me that lesson.


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## lsm

thehatedguy said:


> I might would look at the DE120 and DE400 from B&C over the DE500s. You can get those in a mylar or a titanium diaphragm, pretty smooth response, about the same low end, and cheaper. Never heard either one though. But I generally like mylar/plastics and aluminum over titanium domes though the D2500 and DE500s sound really good.
> 
> Some things to look at and to keep in mind though...given you have two drivers that are pretty much the same, the driver with the higher Bl will generally have the better treble response due to having more motor to drive the air load in the horn. Look at the BMS drivers, the 4550 and the 4552- the 4552 is neo and has more motor and has better treble...same goes for all of the Radian drivers- they are all pretty much the same driver except you get more motor as you move up the model range, and the treble gets better.
> 
> Master Eric taught me that lesson.


WTH Eric you never taught ME that lesson.....lol 

All hail thehatedguy :bowdown:


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## thehatedguy

But it was like...yeah, that makes total sense now that you think about it. I'm sure Eric has more advanced lessons to teach too...lol.

He might would have said that if you weren't using the wrong horn bodies . j/k


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## lsm

subwoofery said:


> Driver+horn dictate how low it can play
> Driver dictates high frequency roll-off
> 
> A driver that can play really low won't be playing much past 12kHz for eg.
> 
> Kelvin



With that said I see a lot of talk in this section about adding bullet tweeters to extend out the freq. but I've never seen any suggestions...

What drivers would work best for this application and what is the optimal mounting location? I'm going to guess it depends on your image: mount them forward if you need more depth and high and wide if you need width.


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## lsm

thehatedguy said:


> But it was like...yeah, that makes total sense now that you think about it. I'm sure Eric has more advanced lessons to teach too...lol.
> 
> He might would have said that if you weren't using the wrong horn bodies . j/k



Haha! Believe me there are more ES horn bodies in my garage than anything else...kinda hard to argue with the master......but this damn forum won't just let me leave well enough alone


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## thehatedguy

As far as super tweeters, you want/need (IMO) something as efficient or more efficient than the horns...so with that in mind, they will be pretty large. There are a lot of them out there, just they are hard to put in a car.

I have Beyma CP21/fs in my Edgarhorns and like them a lot (I did, haven't played them in 5+ years- didn't have anywhere to put them until now, and no amp for them now).

The Fane ST5022s were used in Dr. Edgar's top of the line speakers. A lot of home guys like the Fostex tweeters. The FT96 was Dr. Edgar's recommended replacement for my horns, but they were out of production at the time and have came back in the last couple of years. The T90/T900T925 and uber expensive T500 are really well liked in the home...but they are BIG, expensive, and would be hard to mount in a car.

I've heard the Ciare 138 was pretty nice.

And I've heard the Selenium ST350 could be really nice.

Now I bet the B&C DE5 and DE7 in a small, shallow waveguide would make a nice super tweeter. I've used the DE5 and really liked it.

But compression drivers have gotten better in the treble since back in the day. Some say that up past 10k really isn't that important.

Horn guys don't get that "airy" treble because they tend to beam the treble moreso than direct radiators, and the narrow dispersion causes that.


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## thehatedguy

I've owned a few Veritas horns myself and really liked them once I kept them from ringing. And I always give props to the old Illusion horns...I really liked the couple sets that I heard.



lsm said:


> Haha! Believe me there are more ES horn bodies in my garage than anything else...kinda hard to argue with the master......but this damn forum won't just let me leave well enough alone


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## lsm

thehatedguy said:


> I've owned a few Veritas horns myself and really liked them once I kept them from ringing. And I always give props to the old Illusion horns...I really liked the couple sets that I heard.


If I didn't have a clutch pedal to fight with I would have liked to try the Illusions. I did like the sound of both Veritas but at the end of the day I'll still be running Eric's horns. He's taught me and helped me a ton over the years and that deserves my respect & support. Still fun to play though...


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## thehatedguy

Did you find any Illusions to play with?


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## lsm

Not for sale but I did have a few people here on the forum offer to let me borrow theirs. This is such a great community!


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## subwoofery

lsm said:


> With that said I see a lot of talk in this section about adding bullet tweeters to extend out the freq. but I've never seen any suggestions...
> 
> What drivers would work best for this application and what is the optimal mounting location? I'm going to guess it depends on your image: mount them forward if you need more depth and high and wide if you need width.


Always wanted to try this driver: 
Beyma CP21F - Beyma CP21F 1" high frequency slot tweeter. Beyma speaker components available at US Speaker. 
The controlled vertical dispersion should help minimize reflection coz you need to keep polars in check with horns since they don't throw sound the same way as a normal piston driver... 

Kelvin


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## roduk

Very interesting and I hope this conversation continues. I'm using DE250's on a set of Veritas and would love a driver that gives me that top end sparkle… Am I right in holding out for a pair of TAD 2001s ??


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## lsm

roduk said:


> Very interesting and I hope this conversation continues. I'm using DE250's on a set of Veritas and would love a driver that gives me that top end sparkle… Am I right in holding out for a pair of TAD 2001s ??


If you can get them to fit yes. You'd think they would have come down in price by now but I guess that just shows how good they are. I'm surprised that with all the advancements in design they haven't been bested...


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## cajunner

with 3-D printing, someone will likely come along and best the phase plug design of the TAD, and if you had a beryllium print head, haha...


but seriously, how old is the TAD 2001 now, and why do they still cost so much, or why are they considered state of the art, this many years later?


is it the alnico properties? is it the beryllium tooling costs? is it the need in pro audio for a driver with it's unique properties is outmoded, because ceramic magnet/large diaphragm compression drivers are more durable?

Just seems like a niche market waiting for some tinker to exploit...


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## roduk

None of the above - it's just nutcase audio buffs with too much disposable income and they have an internet following to die for..!!


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## cajunner

there's always GOTO and ALE and those field magnet driven get-ups too, if it's money you're looking to squander..

or the original Western Electric 555's, is it?

why they so fly?

looks like a junky phenolic diaphragm with phase plug issues, high internal losses and resonant modes...


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## Eric Stevens

cajunner said:


> with 3-D printing, someone will likely come along and best the phase plug design of the TAD, and if you had a beryllium print head, haha...
> 
> 
> but seriously, how old is the TAD 2001 now, and why do they still cost so much, or why are they considered state of the art, this many years later?
> 
> 
> is it the alnico properties? is it the beryllium tooling costs? is it the need in pro audio for a driver with it's unique properties is outmoded, because ceramic magnet/large diaphragm compression drivers are more durable?
> 
> Just seems like a niche market waiting for some tinker to exploit...


The TAD is what it is because it was done with a no compromises approach. They are priced well above what they should be because of Pioneers business model for TAD. The TAD2001 is not a sound reinforcement driver but more for monitoring and systems where the highest fidelity is the driving factor in system design. 

Alnico is a lower distortion magnet material, but then so is neodymium. The diaphragm is very expensive to make as it is manufatured by vapor deposition on a copper form.

Eric


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## cajunner

Eric Stevens said:


> The TAD is what it is because it was done with a no compromises approach. They are priced well above what they should be because of Pioneers business model for TAD. The TAD2001 is not a sound reinforcement driver but more for monitoring and systems where the highest fidelity is the driving factor in system design.
> 
> Alnico is a lower distortion magnet material, but then so is neodymium. The diaphragm is very expensive to make as it is manufatured by vapor deposition on a copper form.
> 
> Eric


I get that, and in 1982 when focused field geometry made for loud JBL, I saw an improvement from the current state of the art.

but we're so far past that now, the TAD was designed using engineering from the sixties, I just don't understand how it is that the beryllium tooling processes from today, cannot deliver a superior diaphragm, I don't understand how the newest CAD designs cannot achieve a higher flux and more compact, and stable motor, that the TAD is still alone, not surrounded by prettier, younger specimens on the catwalk...

and sure, a brilliant acoustic physicist, perhaps Japanese, perhaps profoundly gifted, was able to devise the geometry and the hazardous vapor deposition technique requires extra on the manufacturing end, but is that the best available technology?

Is a company like Harman, unable to compete with all their engineering departments focusing on motors and thermal management, couldn't they have had someone socked away in a corner doing better than CMMD methods, is the copper etching really creating an organic crystalline metallic structure for beryllium, or is that just the way that works?

I don't know, Eric. I like to think that for all it's technical elegance and engineering the TAD design has become dated, it's reign over lesser drivers finally nearing an end. 

Isn't there some serious product coming out of JBL labs today, that delivers on that notion? I read some stuff recently, maybe nobody took those new drivers out of package yet for the car, considering price and all, maybe it's time to audition the new against the old. One thing is glaringly obvious though, it won't be me disassembling 50K speakers so I can stick a horn under a dash, but someone might.


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## Eric Stevens

FYI, the TAD was engineered here in the USA by an ex JBL engineer.

Eric



cajunner said:


> I get that, and in 1982 when focused field geometry made for loud JBL, I saw an improvement from the current state of the art.
> 
> but we're so far past that now, the TAD was designed using engineering from the sixties, I just don't understand how it is that the beryllium tooling processes from today, cannot deliver a superior diaphragm, I don't understand how the newest CAD designs cannot achieve a higher flux and more compact, and stable motor, that the TAD is still alone, not surrounded by prettier, younger specimens on the catwalk...
> 
> and sure, a brilliant acoustic physicist, perhaps Japanese, perhaps profoundly gifted, was able to devise the geometry and the hazardous vapor deposition technique requires extra on the manufacturing end, but is that the best available technology?
> 
> Is a company like Harman, unable to compete with all their engineering departments focusing on motors and thermal management, couldn't they have had someone socked away in a corner doing better than CMMD methods, is the copper etching really creating an organic crystalline metallic structure for beryllium, or is that just the way that works?
> 
> I don't know, Eric. I like to think that for all it's technical elegance and engineering the TAD design has become dated, it's reign over lesser drivers finally nearing an end.
> 
> Isn't there some serious product coming out of JBL labs today, that delivers on that notion? I read some stuff recently, maybe nobody took those new drivers out of package yet for the car, considering price and all, maybe it's time to audition the new against the old. One thing is glaringly obvious though, it won't be me disassembling 50K speakers so I can stick a horn under a dash, but someone might.


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## Patrick Bateman

thehatedguy said:


> I think the DE500s and D2500s are a step up from the DE200s used in the CD1 Pros IMO, better midrange. There are a lot of new drivers on the market that I haven't played with that look to be really nice. A lot of the "ultimate" driver depends on how low/high you want them to play, the physical size you are limited to, and your budget. If you are using minihorns then that would limit how low you would want/need the drivers to play.
> 
> But there are some like Dr. Geddes and Tom Danley who say compression drivers for the most part are commodity items and after EQ there is minimal difference in their performance. I can see where they are coming from, but still don't know if I buy into that line of thought 100% yet.


Geddes has been pretty vocal about that, basically saying that a $150 B&C is sonically indistinguishable from a $2000 TAD.

I don't get the impression that Danley is coming from the same mindset. I can't speak for the guy, but based on what I've read and studied, Danley is very VERY focused on the shape of the wavefront.

Danley was using B&C until the guys at Yorkville demonstrated that the BMS compression drivers worked better. And by 'better' I mean better polar response.

This next part is about to get super confusing so PLEASE ask questions if what I'm about to say doesn't make sense.










In a conventional compression driver, the diaphragm is larger than the throat.
The phase plug takes the energy from the compression driver, and it focuses it into a flat wavefront.

The problem is that the focus is converging.


















BMS uses a ring, and because of the ring shape, the wavefront is a better match for the throat of the waveguide or horn. IE, if you draw a straight line from the edge of the ring to the edge of the throat of the horn, *the distance is the same at every point on the ring.* That might seem like a subtle thing, but it makes a difference, because 20khz is 1.7cm. So an error of even a fraction of a centimeter counts.

If you look at the polar response and frequency response charts of BMS compression drivers, they are superior to B&C in the top octave. (10khz-20khz.)

If you don't need a lot of output, or you don't want to spend $150, there's a simpler way to get a similar effect.









Just use a smaller compression driver. In this pic, you can see that the Celstion CDX1-1425 and the BMS 4540ND have a diaphragm that's barely larger than a dome tweeter.

There's a $40 Celestion that looks really well suited to this, basically similar to a B&C DE250 but 2/3rds the size.


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## Patrick Bateman

cajunner said:


> I get that, and in 1982 when focused field geometry made for loud JBL, I saw an improvement from the current state of the art.
> 
> but we're so far past that now, the TAD was designed using engineering from the sixties, I just don't understand how it is that the beryllium tooling processes from today, cannot deliver a superior diaphragm, I don't understand how the newest CAD designs cannot achieve a higher flux and more compact, and stable motor, that the TAD is still alone, not surrounded by prettier, younger specimens on the catwalk...
> 
> and sure, a brilliant acoustic physicist, perhaps Japanese, perhaps profoundly gifted, was able to devise the geometry and the hazardous vapor deposition technique requires extra on the manufacturing end, but is that the best available technology?
> 
> Is a company like Harman, unable to compete with all their engineering departments focusing on motors and thermal management, couldn't they have had someone socked away in a corner doing better than CMMD methods, is the copper etching really creating an organic crystalline metallic structure for beryllium, or is that just the way that works?
> 
> I don't know, Eric. I like to think that for all it's technical elegance and engineering the TAD design has become dated, it's reign over lesser drivers finally nearing an end.
> 
> Isn't there some serious product coming out of JBL labs today, that delivers on that notion? I read some stuff recently, maybe nobody took those new drivers out of package yet for the car, considering price and all, maybe it's time to audition the new against the old. One thing is glaringly obvious though, it won't be me disassembling 50K speakers so I can stick a horn under a dash, but someone might.






























The JBL 2430K seems to be a real world beater.
The MSRP on them is probably north of two thousand, but you'll see them on eBay for under $500.
The ones on eBay aren't from the M2 monitor, they're from a Vertec array that's used in stadiums and the like, but it appears to be the same part.

Here's some light reading on the 2430K, which is another ring radiator.

JBL Master Reference Monitor


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## Eric Stevens

Patrick,

I dont want to get into full on techincal discussion, but you are missing some key points.

The dome being larger than the throat/exit creates compression, hence the term compression driver. The larger dome doesnt cause the wavefront to be focused or reshaped as you describe.

The large format ring radiator style of driver like the BMS will do better at 10Khz to 20Khz range due to design and operating characteristics, not that the wavefront is a better match for the throat IMHO. The primary design features that improve high frequency reproduction are 1- lower diaphragm mass, 2-higher frequencies are only radiated near the voice coil and a ring radiator uses the output from both sides of the voice coil where a dome style driver only one side...Further to this the BMS design simplfies the phase plug design.

A phase plug in a compression driver is designed so that the distance from each slit to the drivers throat is equal. A driver with a 4" diaphragm such as the cutaway of the 4001 you show will only work really well up to about 12Khz if memory serves me correctly since it is impossible to get them exactly the same distance. With a conventional compression driver you could achieve similar results by only have a single slit at the outer edge near the voice coil. Even the large BMS drivers dont work well at the higher frequencies so they make them in coaxial versions to cure this problem. Just as in a the horns we attach to the driver there is an area progression that starts at the phase plug and continues to the exit of the driver in all compression driver designs, at some point it is not going to be a pure wavefront anymore in all designs, a ring radiator design will not magically produce a pure wavefront better than a conventional dome style compression driver.

Eric


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## Patrick Bateman

Eric Stevens said:


> Patrick,
> 
> I dont want to get into full on techincal discussion, but you are missing some key points.
> 
> The dome being larger than the throat/exit creates compression, hence the term compression driver. The larger dome doesnt cause the wavefront to be focused or reshaped as you describe.
> 
> The large format ring radiator style of driver like the BMS will do better at 10Khz to 20Khz range due to design and operating characteristics, not that the wavefront is a better match for the throat IMHO. The primary design features that improve high frequency reproduction are 1- lower diaphragm mass, 2-higher frequencies are only radiated near the voice coil and a ring radiator uses the output from both sides of the voice coil where a dome style driver only one side...Further to this the BMS design simplfies the phase plug design.
> 
> A phase plug in a compression driver is designed so that the distance from each slit to the drivers throat is equal. A driver with a 4" diaphragm such as the cutaway of the 4001 you show will only work really well up to about 12Khz if memory serves me correctly since it is impossible to get them exactly the same distance. With a conventional compression driver you could achieve similar results by only have a single slit at the outer edge near the voice coil. Even the large BMS drivers dont work well at the higher frequencies so they make them in coaxial versions to cure this problem. Just as in a the horns we attach to the driver there is an area progression that starts at the phase plug and continues to the exit of the driver in all compression driver designs, at some point it is not going to be a pure wavefront anymore in all designs, a ring radiator design will not magically produce a pure wavefront better than a conventional dome style compression driver.
> 
> Eric


Here's some quotes from Danley that explain the 'ring vs dome' thing better than I can.
*The main reason I replied to Jason's post was because I've read that Danley is using ring radiators to get a specific wavefront, not because they're cheap.* In fact about half of his speakers use drivers at the throat that cost as much as 3-4x as much as the competition. (Various BMS coax models.)

If I'm not mistaken, there isn't a single Danley speaker that uses anything but BMS for the high frequencies. JBL's flagship also uses a ring radiator, the D2430K. *There definitely seems to be some heavy hitters betting on this technology.*

Here's the quotes:

Beyond the Ariel - Page 146 - diyAudio

_"Hi Lynn, Earl, all

Sorry for popping in so late in the thread but I would offer a few comments as well.
For one, little (good) has been said here about the conical horn, yet, its walls have the least change (none) one can have, it is a segment of spherical radiation space bounded by a physical boundaries and if driven at an acoustically small point, radiates a section of spherical wave front, with the effectively the same arc, regardless of frequency, down to where its mouth size losses control.
The nonlinear (shocking up) distortion in air is also less in a conical horn as its initial expansion is very rapid. This problem is sort of a “wavelengths traveled times the SPL” issue so a Hyperbolic would be worse than exponential of the same mouth and low cutoff etc.

*Not all compression drivers are created equal or create the same problems. 
For example, in subjective listening, on two identical 50 degree conical horns, both made “flat”, both having similar responses and acoustic phase, still sounded very different.
Of two of the best modern compression drivers available, The B&C DE250 sounded very much like a horn compared next to the BMS 4550 which sounded very “open” and airy. 

The possibly interesting part was the BMS driver has a different internal approach, which so far as the horn is concerned, starts as an acoustically small conical horn inside the driver. There are no phase plug summation slots, (which by path length, generally would appear to produce a converging, not diverging wave front one would want in a source that was large enough to already exhibiting some directivity at the throat).
As a result, with an acoustically small origin and small acoustic size where the break point in angles was, there was much less “origin” garbage from the BMS style phase plug arrangement which produces a diverging wave front from inside the driver.*

Yes, mouth diffraction is an issue with horns, not popular but for any given shape, the larger you make it, the less of a problem it is because the SPL is always falling as you move from the origin.

One practical down side of conical or other constant directivity devices is that they reveal the drivers true power response which makes hifi folks uneasy, a truth they don’t want to see or have to deal with as “things are suppose to be flat”.
A related down side is that the conical horn (for a given size) exhibits somewhat less low frequency loading on the driver due to its rapid initial expansion also.

There are solutions to most things, practical or not is another issue.
I have been working with a company on a new phase plug geometry for dome compression drivers, so far, that seems to work too.
Anyway, some thoughts on a Saturday morning.
Best,

Tom Danley"_

Best horn/compression drivers for music? - Page 11 - diyAudio
_"The BMS 4550 is a non-dome driver and has a couple nice things going for it.
For one, the impedance peaks at the low end of it’s response are lower than most 1 inch drivers and this makes the high pass crossover easier if passive (like many of ours are).
Second though is something which may or may not be important depending how it’s used. Sound travels at the speed of sound of course and so if one examines the relationship of the radiator, phase plug and exit, one finds that these relationships can vary quite a bit.
That matters because except near breakup, the dome acts like a piston and so when you trace the path lengths from the dome through the phase plug, one finds that some drivers would produce a converging wave front at the exit, while others a plane wave and a few a diverging wave front. 

With our horns, the goal is to make them act like they were a single point source driver and so at 20KHz where the exit would be having an effect on the pattern, that is reduced / eliminated by having a source that already has curvature to it. 
That is partly why I use conical horns too, the sound does not have to change or refract like can happen if the horn wall angles changes too much / quickly before the pattern is established. 
A simple conical horn driven by a point source (a source that is too small to have directivity) radiates a simple portion of a sphere. 
That way, the entire angular distribution is more even, has no hf character or an interference pattern when you walk past it playing pink noise. A source that produces an interference pattern will have an audible to very audible combing with pink noise when you walk the pattern."_


----------



## Patrick Bateman

Eric, one thing you might find interesting is that JBL is actually varying the pathlength *on purpose*.

It's interesting, because conventional phase plug geometry makes the wavefront flat. But now they're varying those pathlengths intentionally, likely to smooth out the frequency response. For instance, if there was a dip or a peak in the frequency response that was caused by geometry, varying the pathlengths will reduce the severity of the peak or the dip.

Kind of interesting stuff.



















































The BMS 4540ND and the JBL 2408H are a great example of this.
First two pics are the JBL.
All the other pics are my BMS 4540NDs.
The two drivers are very similar, with a ring radiator, but the JBL has a *square* phaseplug. The combination of a round diaphragm and a square phase plug varies the pathlength.

NEAT 


















See how the JBL (top) is smoother than the BMS (bottom)?
Of course, this is subtle difference and only affects 10-20khz, but everything counts right?


----------



## cajunner

Eric Stevens said:


> FYI, the TAD was engineered here in the USA by an ex JBL engineer.
> 
> Eric



thanks, my mistake.

I remember reading about horn geometries on the internet and I knew there was a correlation between some JBL product and the TAD, but what would it take to make a better driver? Is present day technology not sufficient to create either a more economical substitute that performs as well, or a superior performing process?

either way, it seems to me that if this TAD is special in this way that Faberge eggs are special, or Stradivarius violins are special, couldn't science at least create a nearly perfect approximation for 1/4 the cost?

thanks to you and Patrick Bateman's recent contributions, this thread has become quite interesting again.


----------



## cajunner

Patrick Bateman said:


> The JBL 2430K seems to be a real world beater.
> The MSRP on them is probably north of two thousand, but you'll see them on eBay for under $500.
> The ones on eBay aren't from the M2 monitor, they're from a Vertec array that's used in stadiums and the like, but it appears to be the same part.
> 
> Here's some light reading on the 2430K, which is another ring radiator.
> 
> JBL Master Reference Monitor


kind of cheating, though isn't it?

dual driver apparatus is like a mini-Unity horn, in that there is the additional complexity with perhaps, only incremental performance improvement.


but then, incremental improvement is probably as good as it gets, considering how few options seem to be ignited using the same modeling, and mathematics.


----------



## Eric Stevens

I have never put much thought into the shape of the wavefront. Something interesting things to ponder are the shape of the wavefront and how it will interact with the horn. My initial thought is the horn will dominate at frequencies that are not directional yet and the fact that its is a converging, flat or diverging wavefront wont matter much. What is going to matter most in how things sound is the power response.

To compare the different drivers you need to look at plane wave tube measurements or measure them on the same horn. 

I have had lengthy discussions with the founder of BMS and done plenty of listening and measuring of BMS drivers also. While they did many things better than the drivers they were being compared to I always preferred other drivers over them from an overall listening enjoyment standpoint. This is comparing them on Edgarhorn systems and on my horns and not just once but multiple times with the original large format coax BMS and an improved revision of the BMS coax. With the smaller drivers they always had excellent air and detail in the upper registers (> 8Khz) but lacked the midrange of the drivers they were being compared to and with all the fundamental frequencies being below 6Khz having the better upper midrange makes the other drivers a more enjoyable listening experience. 

Eric


----------



## Eric Stevens

I think a substitute or even improvement could be created that would cost significantly less. 

Would love to play with the D2 driver, it looks rather promising.

Eric



cajunner said:


> thanks, my mistake.
> 
> I remember reading about horn geometries on the internet and I knew there was a correlation between some JBL product and the TAD, but what would it take to make a better driver? Is present day technology not sufficient to create either a more economical substitute that performs as well, or a superior performing process?
> 
> either way, it seems to me that if this TAD is special in this way that Faberge eggs are special, or Stradivarius violins are special, couldn't science at least create a nearly perfect approximation for 1/4 the cost?
> 
> thanks to you and Patrick Bateman's recent contributions, this thread has become quite interesting again.


----------



## estione

Glad there are some Horn fanatics on here, Some great reading on here, I seriously want to go horn install, But being in the UK there is not much call for it, Shame if only they knew what they are missing !!!!


----------



## Patrick Bateman

Eric Stevens said:


> I have never put much thought into the shape of the wavefront. Something interesting things to ponder are the shape of the wavefront and how it will interact with the horn. My initial thought is the horn will dominate at frequencies that are not directional yet and the fact that its is a converging, flat or diverging wavefront wont matter much. What is going to matter most in how things sound is the power response.
> 
> To compare the different drivers you need to look at plane wave tube measurements or measure them on the same horn.
> 
> I have had lengthy discussions with the founder of BMS and done plenty of listening and measuring of BMS drivers also. While they did many things better than the drivers they were being compared to I always preferred other drivers over them from an overall listening enjoyment standpoint. This is comparing them on Edgarhorn systems and on my horns and not just once but multiple times with the original large format coax BMS and an improved revision of the BMS coax. With the smaller drivers they always had excellent air and detail in the upper registers (> 8Khz) but lacked the midrange of the drivers they were being compared to and with all the fundamental frequencies being below 6Khz having the better upper midrange makes the other drivers a more enjoyable listening experience.
> 
> Eric


I think that drivers like the TAD can sound very good on an Edgarhorn.
But I think that the wavefront shape is a big part of that.


















In the first pic, we have an Edgarhorn.
In the second pic, we have a QSC waveguide.

Though the size of the mouth is similar, *the QSC is dramatically shallower.* And the angle is much, much wider.

If you look at the polar curves posted in the thread 'great waveguide list', over at diyaudio, *you'll notice that sometimes the sound is basically 'detached' from the horn walls.

The way that this happens is that the width of the walls is wide, and the sound coming out of the throat is converging, so the wavefront basically doesn't 'see' the walls!

Of course one easy way to make it 'see' the walls is to simply make the walls narrower, and the Edgarhorn has a much narrower throat.

Of course all of this is a bit academic, because it's only an issue with horns that have a wide coverage angle. In car audio our horns are so tiny, relative to the wavelength, the sound *always* sees the walls.

Are you going to Vegas for CES? It's a bummer I didn't get a chance to meet up last time, and I'm still on the fence as to whether I'll go.
*


----------



## cajunner

Eric Stevens said:


> I think a substitute or even improvement could be created that would cost significantly less.
> 
> Would love to play with the D2 driver, it looks rather promising.
> 
> Eric


It's quite interesting, isn't it?

although, with all that engineering prowess, why couldn't they take those two first 90 degree bends out, by turning the motors on an up and down axis?

I don't think of the wavefront shape, as much as I do the "hydro-dynamics" of the compression environment and when you force the air through bends.

so, make a dual annular ring radiator that has really no bends in it, by making the motors concentric with the smaller interior ring motor just engineered for equivalent energy, so they can combine their power response without...


well, it's an idea. Not ideal, as the complexities of making dual motors, one inside the other, of the same general gap strength, and the diaphragms of the same general Sd with drastically different diameter...

this engineering of good ideas is harder than it looks.


anyways, I think the reason for the cheaper, but more complex D2's motor being special has a lot to do with twice the motors, as it's always about the gauss, with compression drivers and air loads...

and the power handling of a dual coil operation, can't forget that little factogram, eh?


Just turn the motor structures sideways and run your gap vertical, leave out those square edged turns...

seems easy enough, I mean I think I can see it...


----------



## cajunner

Patrick Bateman said:


> The JBL 2430K seems to be a real world beater.


and thanks for posting this, Patrick.

spent time in that LH thread, they sure like to build it up a bunch, don't they?

it does sure look good for a car audio version, maybe with even smaller sized component parts, engineered for 1/4 power application with more emphasis on the polymer flexing for excursion and less vigorous in the power handling, like half the build strength of that plastic diaphragm, because you don't need that much output for the car.

a more pro-sumer version than full-on PA style l think.


let's get on that...


----------



## cajunner

here's a bombshell idea!


(and I haven't had my coffee yet...)


what about making a D2 in the Piezo drive motor format?

that would be pretty cool, I think.


and light weight, give me a sketch artist and I'll give you a portrait of it, the dual motors Piezo may be strong enough to get down in the lower frequencies, where it seems to run out of gas in the regular compression driver format, like the Motorola design.

then we could put that sucker in the engine compartment and use the floorboard in an EOS waveguide by just whacking the sheet metal under the pedals, and bolting it on...


hahha..


----------



## Patrick Bateman

cajunner said:


> It's quite interesting, isn't it?
> 
> although, with all that engineering prowess, why couldn't they take those two first 90 degree bends out, by turning the motors on an up and down axis?
> 
> I don't think of the wavefront shape, as much as I do the "hydro-dynamics" of the compression environment and when you force the air through bends.
> 
> so, make a dual annular ring radiator that has really no bends in it, by making the motors concentric with the smaller interior ring motor just engineered for equivalent energy, so they can combine their power response without...
> 
> 
> well, it's an idea. Not ideal, as the complexities of making dual motors, one inside the other, of the same general gap strength, and the diaphragms of the same general Sd with drastically different diameter...
> 
> this engineering of good ideas is harder than it looks.
> 
> 
> anyways, I think the reason for the cheaper, but more complex D2's motor being special has a lot to do with twice the motors, as it's always about the gauss, with compression drivers and air loads...
> 
> and the power handling of a dual coil operation, can't forget that little factogram, eh?
> 
> 
> Just turn the motor structures sideways and run your gap vertical, leave out those square edged turns...
> 
> seems easy enough, I mean I think I can see it...


A few observations:

















1) The first pic shows the 90 degree bend that you've mentioned. The secone pic shows an exploded diagram of the D2430K. I agree, 90 degree bends are A Bad Thing, but the bend in the D2430K is ultra short. It appears to be less than one centimeter. I'm really fascinated by the square phase plug that's used, and I wonder what the effect is. A few years back I found that the 90 degree bend in the USD horns creates a notch in the upper midrange, around 1500hz iirc. Since these dips and peaks are geometric, and the D2430K is exceptionally smooth, perhaps varying the geometry reduces those peaks and dips?

JBL 2408H-1 Compression Driver 365011-001X | Speaker ExchangeSpeaker Exchange

2) The JBL 2408H-1 is an interesting little driver, seems to combine a lot of the features of the D2430K (square phase plug, ring radiator) but has lower power handling, one voice coil, and costs less than $110. I ordered one last week should have it soon.


----------



## cajunner

Patrick Bateman said:


> A few observations:
> 
> 
> 
> 
> 
> 
> 
> 
> 
> 
> 
> 
> 
> 
> 
> 
> 
> 1) The first pic shows the 90 degree bend that you've mentioned. The secone pic shows an exploded diagram of the D2430K. I agree, 90 degree bends are A Bad Thing, but the bend in the D2430K is ultra short. It appears to be less than one centimeter. I'm really fascinated by the square phase plug that's used, and I wonder what the effect is. A few years back I found that the 90 degree bend in the USD horns creates a notch in the upper midrange, around 1500hz iirc. Since these dips and peaks are geometric, and the D2430K is exceptionally smooth, perhaps varying the geometry reduces those peaks and dips?
> 
> JBL 2408H-1 Compression Driver 365011-001X | Speaker ExchangeSpeaker Exchange
> 
> 2) The JBL 2408H-1 is an interesting little driver, seems to combine a lot of the features of the D2430K (square phase plug, ring radiator) but has lower power handling, one voice coil, and costs less than $110. I ordered one last week should have it soon.


cool...

I look at the way the phase plug perforations are square on the smaller driver, and the 2430K is sort of Manger-looking, with un-even outer perfs, and I would agree that they are taming some potential 'same length resonant peak' sort of geometry, that would lead to FR response fluctuation, or just wreak havoc with HOM in a long flare horn...

it's a lot like when the doctorate guy put a diffraction lens over his 12" or whatever, mid bass so they wouldn't beam before getting a little higher up in the crossover lap.

it had that uneven outer flange, and I think the effect, although related in appearance, may be rooted in geometric fundamentals as well.

I'm not so into the minute detail as whether the TAD or JBL slit patterned phase plugs are inferior to these new square and odd shaped patterns, but more into figuring out how to get small motor body horns to play low without effort or fatigue, and last at higher relative volumes.

Like, would it be possible to do a hybrid, where there is a ring radiator, with a piezo ring radiator in the cavity behind the main diaphragm, and you control the response of the ring radiator's low end by way of servo on the piezo?

like de-pressurizing the cavity, following the signal, for lower tones allowing the ring radiator to have a temporary lower Fs, and things like that.


With the new DSP engines going around I think the possibilities are greater to do active correction at higher frequencies than before, and with a piezo element there's no magnetic issues, it's cheaper to implement and can be beautiful in a tracking/assist kind of way, rather than being the primary transducer element.

I think of it in terms much like the Synergy Horn, Unity Horn, stuff. How do we push the envelope, as the electronics catch up to the transmission of sound in solid materials, so we can get that beryllium accuracy with the polyimide or phenolic budgets.


----------



## Patrick Bateman

That's true, there's a similarity between those three devices:









phase plug on the JBL 2408H-1. Square phase plug combined with a ring shaped diaphragm means that the pathlength varies by a fraction of a centimeter. At 10khz that's a difference of about a quarter wavelength, but by 20khz it's half a wavelength. The effect will be more dramatic in the JBL D2430K, because the ring is 3" in diameter. In the D2430K the variance will be about 1.57cm, or one half wavelength at 10,828hz and one full wavelength at 21.6khz.









Manger bending wave transducer









Diffusor from Doug Winker's car, on top of an 8" JBL iirc


----------



## cajunner

right, this all goes hand in hand with the idea that a wavefront can be flat, or it can be converging, or diverging, or whatever.

beaming is when the size, or diameter of the cone causes the corresponding frequencies to crash into each other, and you get combing effects.

you reduce beaming by putting a barrier phase plug, so the waveform is forced to travel outward from the center before canceling itself out, and extend the FR as a result.

I think that even though we're dealing with slits and perforations and things in these compression drivers, the distances are still totally relevant and the beaming effects are time-dominant, as long as you are dealing with a circular pathway.

the bigger 4" diameters have issues with the higher frequencies, not just because of added mass and thicker materials, but because the geometry of time and space can't be denied.

the biggest obstacle to horns sounding like real music seems to be linked first to HOM and varying the horn shape can make that more or less apparent, but an active control system like DSP that is now being implemented in the Master Reference, can be adapted to acting on higher order modes from the diaphragm's first turn, as in the D2, you make one of the annular ring radiators a servo-tracking distortion reducing circuit.

it's exciting that all of these technologies are coordinating into what is becoming more realistic sounds.

at least I hope so, being I've never yet heard a system like the M2 in person, lol...


----------



## cajunner

I like the idea of using Piezo control devices, because of the accuracy of the mechanics, and although the limitation of movement is a factor, you could do something like Venturi loading, or using an acoustic lever, to provide the necessary changes to the waveform so that it remains not only suitably shaped, but unreactive to HOM.


----------



## Eric Stevens

Patrick Bateman said:


> I think that drivers like the TAD can sound very good on an Edgarhorn.
> But I think that the wavefront shape is a big part of that.
> 
> 
> Are you going to Vegas for CES? It's a bummer I didn't get a chance to meet up last time, and I'm still on the fence as to whether I'll go.


I have never listened to the TAD2001 on an Edgarhorn system. I have heard the 4001 on an Edgarhorn and it wasnt so pleasant, very forward and shouty in it presentation and not rectified completely even with some equalization.

I will be at CES for sure.

Eric


----------



## cajunner

I wonder if you could bring the technologies even closer together, and make not only a diaphragm that is formed from piezo-reactive crystalline properties, but have it locally responsive so the forces that come from the voice coil in the "not in and out direction" can be dissipated right there on the surface, sort of a nano-circuit, or maybe like the Kappa polygraph domes, with the grid energized by piezo lines of force.

this would counteract the deforming vectors that make beryllium a constant in the SOTA diaphragm building processes, and it could even be used to control minor differences in phase plug deformations.

sort of the opposite of GIGO, when you can take away the weaknesses of compression motor design from the start.

yeah, I've been reading too much about this stuff, lol..


----------



## Patrick Bateman

Eric Stevens said:


> I have never listened to the TAD2001 on an Edgarhorn system. I have heard the 4001 on an Edgarhorn and it wasnt so pleasant, very forward and shouty in it presentation and not rectified completely even with some equalization.
> 
> I will be at CES for sure.
> 
> Eric


I'll email you; I'm sure you're busy but if you'd like to talk shop it might be fun!


----------



## cajunner

in a way, you could extrapolate or interpolate or superimpose, or just compare, haha... the way technology increased the speed of computers by taking the high art of Pentium-based design and then adding hyper-threading, then multiplication by cores.

The D2 is like the multiplication of coils, and further advancement into the control of waveforms will depend on this methodology, whereas hyper-threading might be my ideas of using servo diaphragms, Piezo energized or not.

We've seen concentric compression designs, coaxial compression designs, and with the D2 it's a stacked presentation.


I feel like using 2 annular ring radiators, takes away the variable natures of metals and their various issues with work-hardening or propagation of energies, and even durability, along with expansion and contraction to muck it up.

plastics seem more controllable in the changing acoustic physics, overall. Maybe electro-acoustically energizing a diaphragm is too gimmicky in the idea set, just to reduce distortion and I'm thinking past a simpler engineering solution, but so far I've seen people spend enormous amounts of money on purely fabricated, illusions so maybe there's a way forward, just waiting for the next open mind to figure out.

see, we can talk shop right here, Patrick!


----------



## Eric Stevens

With the Edgarhorn systems even with a driver that played all the way up to 20khz or close the system always sounded better when running a super tweeter. I always concluded it was due to power response.

Maybe with a driver that had a diverging wavefront the improved power response would minimize or negate the need for the supertweeter. I am pretty sure that the measured power response would show up the difference in wavefront shapes if this were the case. 

Eric


----------



## BigRed

A little off topic, but could we have a pow wow shop talk dinner at CES for those interested?


----------



## thehatedguy

Eric is that because the tractrix horns are not constant directivity and beam pretty bad up high?


----------



## SQram

Eric Stevens said:


> I will be at CES for sure.
> 
> Eric


Showing off your new line of automotive HLCD's I hope. 

My wallet is ready any time you are...


----------



## bigbubba

SQram said:


> *Showing off your new line of automotive HLCD's *I hope.
> 
> My wallet is ready any time you are...



Or anything other equipment you plan on coming out with.


----------



## Eric Stevens

It would be fun to meet up and talk shop at CES. I won't be showing much as far as new wares go. A preview of things to come is possible but not confirmed.

Eric


----------



## funkalicious

Eric: any hints on what's in the pipeline for new products?


----------



## Horsemanwill

funkalicious said:


> Eric: any hints on what's in the pipeline for new products?


really nice and sexi products


----------



## Broshi

If I was still in the states, I'd be going way out of my way to go to CES to meet up with all of you. My neck of the woods had nothing to work off of. 1% of the 1% of car audio people were well informed about mobile audio which made it a difficult environment to learn as I had no hands on experiences with audio like this. 

Props to those of you who, despite your hectic and dynamic lifestyles, continue to provide crucial and accurate information to those of us that seek it. Perhaps I'll find my way into the States again and run into some of you sometime.


----------



## Eric Stevens

funkalicious said:


> Eric: any hints on what's in the pipeline for new products?


New products are audio related 



A full line of products from coaxials, components, subwoofers and amplifiers. Nothing off the shelf, all completely original designs with many unique features. 

For example
6.5" (165mm) cast AL basket Mid-bass with underhung motor and 5.5mm one way Xmax all windings in the gap with SPLo at 90.5 dB 1w/1m and Sd just under 150 cm2. Pe will be in excess of 200 wrms with very low power compression. Have your cake and eat it too  SQ, dynamics and very high output.

Eric


----------



## SQram

Eric Stevens said:


> A full line of products from coaxials, components, subwoofers and amplifiers.
> 
> Eric


Hmmmm...no mention of HLCD's...

Poop


----------



## jking29

Eric Stevens said:


> For example
> 6.5" (165mm) cast AL basket Mid-bass with underhung motor and 5.5mm one way Xmax all windings in the gap with SPLo at 90.5 dB 1w/1m and Sd just under 150 cm2. Pe will be in excess of 200 wrms with very low power compression. Have your cake and eat it too  SQ, dynamics and very high output.
> 
> Eric


Any idea of a time frame or ballpark price point on these? epper:


----------



## Eric Stevens

SQram said:


> Hmmmm...no mention of HLCD's...
> 
> Poop


They werent excluded either 

New developments for the HLCD will happen after the launch/release of the other products. For now it will contimue with the current horns and drivers.

Eric


----------



## Eric Stevens

jking29 said:


> Any idea of a time frame or ballpark price point on these? epper:


Announcements in due time 

Eric


----------



## SQram

Eric Stevens said:


> They werent excluded either
> 
> New developments for the HLCD will happen after the launch/release of the other products. For now it will contimue with the current horns and drivers.
> 
> Eric


I'm throwing money at my computer screen and nothing is happening!!! 


Best of luck Eric, I eagerly await your product/company launch.


----------



## Eric Stevens

SQram said:


> I'm throwing money at my computer screen and nothing is happening!!!
> 
> 
> Best of luck Eric, I eagerly await your product/company launch.


You have to hit the send button 

Eric


----------



## lsm

SQram said:


> I'm throwing money at my computer screen and nothing is happening!!!


Hahahahahaha


----------



## SQram

Eric Stevens said:


> It would be fun to meet up and talk shop at CES. I won't be showing much as far as new wares go. A preview of things to come is possible but not confirmed.
> 
> Eric


OK, CES is here. Can we see the previews???

Please?


----------



## Horsemanwill

ces just started he's probably there now.


----------



## bigbubba

I'd like to bring this topic back up. I'm using the Selenium D2500TI ND driver on my ID full body. I wanted to see what drivers other people have used and their thoughts on them. I'm fairly happy with mine but wanted to know if there was a better driver out there that will fit my horns. Mostly what I've read so far are thoughts on Edger horns and drivers that are too big to be used effectively in an automotive environment.


----------



## thehatedguy

Have a budget and size restraint?

I hear the Celestion compression drivers are really really excellent.


----------



## Patrick Bateman

thehatedguy said:


> Have a budget and size restraint?
> 
> I hear the Celestion compression drivers are really really excellent.


Love 'em. I've tried BMS, B&C, Celestion and JBL. My favorite 'bang for the buck' are the Celestions. I was a big fan of the JBL 2408H-1, as it was as good as the BMS but cheaper, but it's become more expensive lately. The price of neodymium seems to vary constantly.









Red line is a measurement of the $45 Celestion CDX1-1445. More high frequency extension than the B&C 1" and all of it's clones, and cheaper.


----------



## bigbubba

thehatedguy said:


> Have a budget and size restraint?
> 
> I hear the Celestion compression drivers are really really excellent.


I don't think I can go too much bigger than the drivers I have now. Budget wise...Don't think I would want to go more than $300 a pair.


----------



## thehatedguy

The problem is those are some of the smallest drivers around.

How low are you playing them?


----------



## bigbubba

thehatedguy said:


> The problem is those are some of the smallest drivers around.
> 
> How low are you playing them?


I'll have to stick my head back under the dash to see what kind of room I have left around them. I'm wanting to say I had an issue with space on the passenger side but it was more with the driver mounting flange of the horn.

They are crossed down to 1.25Khz.


----------



## lsm

Bumping this back up to keep the conversation going...


----------



## Diezel10

Mic10is said:


> and the size of a coffee can a very heavy coffee can, like a 16lb coffee can....image trying to support that on the backside of a horn


TAD 2001's currently installed in a 2006 Dodge mega cab, supported by a custom bracket, a flange within a flange and tabs protruding from each side to strap or bolt on. 

I am using Veritas Aluminum bodies, and Thanks to Eric for providing the instruction on how to clean the beryllium diaphragms.


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## lsm

Diezel10 said:


> TAD 2001's currently installed in a 2006 Dodge mega cab, supported by a custom bracket, a flange within a flange and tabs protruding from each side to strap or bolt on.
> 
> I am using Veritas Aluminum bodies, and Thanks to Eric for providing the instruction on how to clean the beryllium diaphragms.


I'd love to see some pics of your install!


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## SQram

Indeed, get some pics up please!!


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## Diezel10

Good Morning, 
Wont let me load pics....I have the pics of the Horns in the Post where OP is requesting pics of horns installed.



D


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## lsm

Has anyone ever tried the Pioneer PD-801 Compression Driver? They are supposed to be an early version of the TAD 2001 and they use the same diaphragm. The reason I ask is they are much less expensive... There's a working version on eBay now for $159


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## edzyy

Diezel10 said:


> TAD 2001's currently installed in a 2006 Dodge mega cab, supported by a custom bracket, a flange within a flange and tabs protruding from each side to strap or bolt on.
> 
> I am using Veritas Aluminum bodies, and Thanks to Eric for providing the instruction on how to clean the beryllium diaphragms.


How low are you crossing the tad's?


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