[doug s.]

i was under the impresion that a major reason for wanting to use really steep x-over slopes was that so a driver could be used that is optimized for a specific frequency range, w/o have to worry so much how its performance  deteriorates outside this range.  that way, blending of two drivers shouldn't be so difficult, (theoretically), as the distortion component of each driver on either side of the x-over is now so much smaller.  w/the woofer & tweeter having little distortion, this is also supposed to result in a wery connected sound between the two drivers.  with 1st order x-overs, the shallow slopes increase the distortion of the drivers outside their optimal bandpass range, & this contributes negatively to the overall sound, as well as reducing the power handling capacities of the drivers.

everything is a compromise, i guess, eh?  

doug s.

[skrivis]

Or, are you simply referring to the overall phase delay from the bottom to the top of the response?

Overall. Put a signal into a 1st-order crossover, then sum the outputs. What you get out will be what you put in (minus some resistive losses, etc.). You can't do that with higher-order crossovers.

There is disagreement on how important phase "coherency" is, and none of the tests I've seen have been worthwhile. I feel it is very important, and the step function test reveals why most speakers can't pass a transient properly.

All of the tests I have read have some value. Maybe you should conduct the perfect test?

None of the test I have read about ensured that they had a phase-coherent system to begin with. You need that as a control before you can start testing the effect of changes of phase.

Siegfried Linkwitz has some test boards that I may buy so I can see for myself.

Using headphones instead of speakers will likely tell you about amplitude effects, but not time-related ones because they bypass much of our hearing mechanism.

You get solidly into the realm of psycho-acoustics very quickly here.

But, simply put, I feel 1st-order crossovers do less damage to the signal than higher-order ones.

The bad side of 1st-order crossovers is the overlap between drivers, with the consequent lobing and IM.

Lobing will effect power response, but I've already said I'm not sure how important that is. If you then know where the lobe is and plan correctly, the listener will be in the "sweet spot" where the frequency response is more correct (and also where the signal "re-assembles" correctly). It only becomes and issue if you're moving around the listening room.

IM may or may not be a problem. I don't think this has been settled. I've even seen comments that it's beneficial.

Your comment about the blending of drivers being a good thing shows that one man's problem is another's benefit.

I've never seen anyone say that a higher-order standard crossover is superior. What they do say is that the limitations of available drivers force the use of higher-order crossovers.

DEQX could provide the best of both worlds. Phase and time coherent, and steep slope to protect the drivers and keep them linear.

If you assume that you're using a digital input from a CD or something, there will be little added noise from the DSPs. It's all done in the digital domain.

For an analog signal, you're dependent on the quality of the A/D converter, but once you're digital, additional processing won't degrade anything.

I can't really say whether the DEQX box is done well or not. Whether the A/D and D/A converters are good. Whether the thing has enough processing power to do a good job throughout the frequency spectrum. Nor whether the algorithms used are good.

What I can say is that the concept is a good one, and that we'll likely see it used more and more.

The NHT xD system is something I want to listen to. They're using drivers with very stiff cones, but the crossover is steep enough that they don't see signal outside their linear passband. Phase is corrected, so transients are preserved.

I'm not sure whether the amps they use are any good, but I'm willing to listen and then decide.

The only real problem I have with them is their use of metal dome tweeters. They're going to break up at high frequencies. DEQX does nothing to stop that. Metal tweeters shriek, in my experience. I wish they had used one of a number of good doped fabric dome tweeters instead. (I like Hiquphon the best, but there are other good ones too.)

[skrivis]

i was under the impresion that a major reason for wanting to use really steep x-over slopes was that so a driver could be used that is optimized for a specific frequency range, w/o have to worry so much how its performance  deteriorates outside this range.  that way, blending of two drivers shouldn't be so difficult, (theoretically), as the distortion component of each driver on either side of the x-over is now so much smaller.  w/the woofer & tweeter having little distortion, this is also supposed to resul ...

It depends upon the drivers. It _is_ possible to get drivers that will handle a 1st-order crossover. The ScanSpeak Revelator series and the Hiquphon tweeter are good examples.

Yes, a 1st-order crossover can cause trouble for the drivers. The standard response is to use a steeper crossover slope to keep the drivers from getting into trouble. An alternative is to seek better drivers...

[David Ellis]

The only real problem I have with them is their use of metal dome tweeters. They're going to break up at high frequencies.

What is the characterstic sound of metal dome tweeters?

What is the characteristic sound of uncontrolled metal diaphram reonance?

Do all metal dome tweeters sound the same?  If not, why?

An alternative (to stiff cones) is to seek better drivers...

Exactly how are they better?

[skrivis]

The only real problem I have with them is their use of metal dome tweeters. They're going to break up at high frequencies.

What is the characterstic sound of metal dome tweeters?

What is the characteristic sound of uncontrolled metal diaphram reonance?

Do all metal dome tweeters sound the same?  If not, why?

An alternative (to stiff cones) is to seek better drivers...

Exactly how are they better?

Metal dome tweeters, to me, sound like bad SS gear. Hard, harsh, gritty, etched, etc. They seem to shriek and call attention to themselves. "Here I am, I'm a tweeter!"

All of the metal dome tweeters I've heard sound the same. This is not to say that there aren't metal dome tweeters that are better.

In my opinion, the big flaw to a dome tweeter is that there's no way to control the center of the dome, except by damping within the dome material itself.

At high frequencies, cones want to become smaller cones. Domes want to become ring radiators.

With a cone, the surround is in the right place to control the bad behavior. With a dome, there's nothing there to control it...

The Accuton metal tweeters claim to have good damping due to the structure of the metal. I would like to hear some speakers using them to see for myself.

Better drivers... there we get into my opinion that "stiff enough" drivers with good damping characteristics are better than stiffer drivers that don't have self-damping.

I would say that the Hiquphon tweeters exemplify my feelings. They're "stiff enough" to produce excellent treble, but they are also well damped _internally in the dome material._

I extend this to drivers for lower frequencies, and feel that "stiff enough" and well-controlled is better than extremely stiff and less well-controlled.

When we get perfect drivers, we'll have extremely stiff materials that also do exactly what the voice coils tell them to do.

In the meantime, it seems that my acceptable compromise is at a different point than yours.

I'm open to argument, and certainly will listen to various designs. I could discover tomorrow that you're right and I'm wrong.

But my current speakers, which have paper composite cone woofers and Hiquphon tweeters, sound very much like what I hear in the recording studio. So I lean towards this approach for now.

I'm certainly not saying that you're wrong. There's plenty of room for differences of opinion. I'm not saying that your speakers are wrong either. You've obviously put a lot of thought and time into the design.

I just feel that, for now, and given my experience to date, I'm in a better place with my current speakers than I would be with yours. ***Please note that I have not heard the Ellis Audio 1801s.*** I could be all washed up since I haven't actually heard them.

[doug s.]

i guess the metal dome tweeter thing is like the tubes vs solid state thing.  (or like the harley-davidson vs all other bikes thing in the motorcycle world.  )  some folk like 'em some folk don't.  personally, i really like the focal metal dome tweets.  i know many folk like these, & i also know many do not.  but, i also like many other non-metal tweets as well...


doug s.

[David Ellis]

With a cone, the surround is in the right place to control the bad behavior. With a dome, there's nothing there to control it...

I believe this comment hits the target very close to the center.  I believe the difference between many good tweeters (fabric or metal) is the surround.  The very valuable dampening of a surround on cone drivers is never overlooked - especially on very well damped (i.e. soft) cones.  As the frequency rises, such cones outer edge will begin to flop in the opposite direction of the inner cone movement.  The well damped surround is obviously needed to control the loose floppy motion of the outer edge of the driver cones.

I can't testify concerning the precise activities of all tweeter domes, but DO believe there is some very valid truth in the surround material.  Certainly there are some that flex in the center, and others that don't.  I DO believe that a fairly rigid tweeter dome will have the properties of a very uniform wavefront.  ASSUMING a relative rigid dome (fabric or metal), the dome must be damped.  There are electrical and mechanical means of accomplishing this.  On the mechanical end of things, I am quite certain the very best tweeters have a damping material on their dome surround.  Applying this material correctly is very tedious, and time consuming.  Also, the exact chemistry of the material is something that's not shared openly.  I am digressing.  

The point of this is that mechanical dampening is a very significant factor in the "zing" of any tweeter.  Cheap tweeters often have a very splashy/zingy sound.  This tends to be more true with metal domes, but remains true with soft domes.  I believe the cluprit is the surround.

I was convinced of this upon listening to the SEAS H1212 tweeter.  It has a metal dome with a wide (and fairly well damped) polymer surround.  THIS tweeter has little/no zing - much less than many soft dome tweeters IMO.  If you have the chance, I highly suggest trying a pair of these tweeters.  The experience was extremely enlightening for me.

In my opinion, the big flaw to a dome tweeter is that there's no way to control the center of the dome, except by damping within the dome material itself.

Indeed, this is why the good tweeters are coated after they are pressed, better tweeters have a separate coating in the center of the dome too.  The process is very artesian.

At high frequencies, cones want to become smaller cones. Domes want to become ring radiators.

What exactly does this mean?

The Accuton metal tweeters claim to have good damping due to the structure of the metal. I would like to hear some speakers using them to see for myself.

Accuton tweeters and driver diaphrams are ceramic.

Better drivers... there we get into my opinion that "stiff enough" drivers with good damping characteristics are better than stiffer drivers that don't have self-damping.

Related questions...

Hint... try not to think about speaker cones.  

Hint #2.  Try to think about these things in terms of waveform energy

What materials absorb sound/sound energy? How do these materals absorb sound/energy?

What materials don't absorb sound/sound energy ?  How do these materials reflect sound/energy?

Dave

[skrivis]

At high frequencies, cones want to become smaller cones. Domes want to become ring radiators.

What exactly does this mean?

Given that we don't have perfectly stiff and massless materials, the voice coil will not be able to perfectly control the cone or dome (diaphragm).

At lower frequencies, the diaphragm is stiff enough and the whole thing moves when the voice coil moves.

At higher frequencies, the voice coil is moving faster than the diaphragm will keep up with. We leave the area of perfect pistonic motion and enter what is usually called breakup. As for as I know, this will happen with all known materials. (Unless you make the diaphragm so think as to appear perfectly stiff at the frequencies of interest, and then you run smack into problems with inertia.)

So the voice coil is attempting to move at 20 KHz. The area of the diaphragm closest to the voice coil will follow along. The farther you get from the voice coil, the less the diaphragm immediately follows the voice coil. You get areas where the diaphragm is out of phase or even in anti-phase.

If you look head on at a dome tweeter, the area closest to the voice coil is an annulus. For a cone speaker, it's a the equivalent of a smaller cone.

If we have enough stiffness, the whole thing moves in phase. If we don't, then we get a smaller radiating surface that's in phase, and then the rest we don't know what it's doing.

I tend to think that a reasonably light and stiff material with good internal damping will have a low enough magnitude in the out of phase areas that it won't cause major problems.

With much stiffer cones, like metal, when they let go they really let go and they're less controlled because of the lack of internal damping. So the magnitude of the output from the out of phase areas is greater and more noticeable.

Some people feel that the damping materials applied to the surface of metal diaphragms is enough to control their misbehavior.

We may be getting closer to that goal, but I've been very pleased with less stiff materials and they sound better to me.

Accuton tweeters and driver diaphrams are ceramic.

You're right. I was thinking of the manufacturing process and misspoke.

I do still question whether Accuton's ceramic is well-damped or not. They claim it is...

What materials absorb sound/sound energy? How do these materals absorb sound/energy?

By converting it into heat.

What materials don't absorb sound/sound energy ? How do these materials reflect sound/energy?

By having enough mass/density/stiffness that the sound waves aren't competent to move them. (That's actually a term from hydrology, but it fits here...)

[David Ellis]

Most excellent.  This is progress in the right direction.  You are saving me a whole bunch of work at the keyboard, and this should read very linear.  I will dispense with further questions, and provide my 2 cents on the issue.  My basic overview is thus:

"You can't have yer' cake and eat it too".

I tend to think that a reasonably light and stiff material with good internal damping will have a low enough magnitude in the out of phase areas that it won't cause major problems.

It sounds like you are middle of the road guy with some tolerance for flexible cones.  This is fine.  I certainly understand the advantages for a simple crossover design.

So the voice coil is attempting to move at 20 KHz. The area of the diaphragm closest to the voice coil will follow along. The farther you get from the voice coil, the less the diaphragm immediately follows the voice coil. You get areas where the diaphragm is out of phase or even in anti-phase.

A very good actual example of this is exists in the response curve for the W18E driver on the SEAS page.  The surround material thickness and type determines the response slightly above 2500hz.  The relative dip between 2500hz and cone resonance at 4200hz is the surround material moving out of phase with the driver.  However, this also means that the CONE of the W18 driver remains a piston up to this frequency range.  The stiff edge of the cone at high acceleration pushes the surround into "whiplash".  

By converting it into heat.

Yep, the only way the well damped material can convert the sound energy into heat is movement.  Insulation fibers are the easiest to understand in this regard.  The do flex when encountering sound waves, and do certainly convert the energy into heat.  What's critically important here is that the dampening material MUST FLEX to convert the energy into heat.  Again, the material must flex to convert the energy into heat.  This truth is critical to this discussion.

Herein, there is are of trade-offs.

Flexible materials produce flexible cones, but will soak-up the internal resonance inside the cone, and allow a shallow slope crossover.

Stiff materials produce stiff cones, but will NOT soak-up the internal resonance inside the cone, and necessitate a steep slope crossover.

There are further trade-offs in cone shape.

Curvalinear cones are more flexible, and push the cone resonance higher.

Straight sided cones have more rigid, but the the cone resonance is lower.

Probably the most credible public example was present on the SEAS web page.  SEAS published the distortion graphs of the 8" Excel metal cone driver and their 8" Excel paper cone driver.  These drivers used the same motor, same frame, same voice coil, and different cones.  The cone weight was nearly identical.  The measured distortion from these graphs was significantly different.   Starting from about 100hz (yes, 100hz) the paper cone driver had significantly more distortion.  Unfortunately these graphs are no longer present.  I don't know of a current parallel example.

It might seem possible to have a stiff cone that is also well damped.  I have encountered ALMOST such a cone.  The SCC300 driver has a VERY thick paper cone with a VERY hard coating.  To the touch, this driver is very stiff.  To the touch, this driver is seems very well damped.  Indeed, this cone was done very well.  It has a nice peaky cone resonance around 800hz - just like a metal cone.

I believe the primary issue with stiff cone resonance is NOT what happens when the voice coil pushes the cone too hard at higher frequencies.  I believe the primary issue is the buildup of acoustic energy INSIDE the cone at higher frequencies.  As the wavelength of the frequency generated by the cone becomes slightly shorter than the diameter of the cone, it will resonate inside the cone.  The soft cone will absorb these frequencies.  The stiff cone will not.  They will reflect immediately from the cone surface into a plume of nasty grunge.  Such is the case with ALL stiff cone drivers I have encountered - SCC300, Accuton C95, SEAS W18E, W18EX, Focal 8k, Seas L17, L18...  .  Caviat, some of these drivers do have compromised curvalinear cone as mentioned above.

I feel compelled to mention there are better cone materials and worse cone materials in their respective categories.  Certainly these can be objectively evaluated.  However, find my subjective ear is darn keen, and follows the distortion measurements.  I believe my current cone material favorites are ceramic (very recently), and paper.  

The summary...  

If you want the cone of a driver to "stop on a dime", it's gotta' be stiff, and it's gotta' reflect sound energy.  It will have a resonance.

If you want to use a 1st order acoustic crossover with a 7" driver at 2500hz, that cone needs to have flexible material, in a flexible cone to absorb the sound energy.  It won't have resonance.

Whew, that was long.  I am going on vacation for 2 weeks this Sunday, and will not return to this issue until the end of July if needed.

Dave

[David Ellis]

Better drivers... there we get into my opinion that "stiff enough" drivers with good damping characteristics are better than stiffer drivers that don't have self-damping.

What truly stiff drivers have you actually measured/tested/implemented/used?  What's your a/b comparison?

[John Ashman]

everything is a compromise, i guess, eh?  

Doug!  If you stay out of politics, you almost sound like know about what you're speaking

Actually, I'd rather comment on a few things:

Cone dampening - If you try to delete the cone resonance of a metal driver, you add mass,  it's largely going to be futile, it drives the resonance and the FR downward and know you have a small driver that has the characteristics of a large driver, but can't move air.  On the other hand, let it ring, keep it as light as possible, then cut it off sharply enough and you have smooth sound and low distortion.  Now, if the future, vapor deposition could allow extremely thin, light multi-laminate structures, but when and for how much?  And, with the advent of steep digital crossovers, does it matter?  I guess we'll have to wait for someone to produce such a cone.  

Metal tweeters - I have to come to the defense of them.  Yes, some domes ring at a frequency that make it bothersome to some, but its rare.  More often, the problem is poor integration, cheap crossovers and a lower resonance, often around 10kHz which is probably due to the motor, not the dome.  I haven't heard a lot of metal tweeters that I've loved but I've heard some.  I haven't heard *any* soft dome tweeters that I've loved.  Stuart, you mention that cones naturally want to ring in the middle of the cone at high frequencies.  That's true - just listen to what kevlar does and, oddly, they do that on purpose and it, well, doesn't sound good.  But imagine a soft dome tweeter.  It's compliant, the *opposite* of rigid.   So, rather than have one obnoxious *ultrasonic* ringing problem, it will have a ton of audible resonances throughout the structure.  It will also absorb some energy and convert it to heat.  So, now you've got a a dome that is both adding and subtracting across the audible bandwidth while metal tweeters don't do this nearly as much.  The tweeter is better behaved on the macro level, but it's a mess at the micro level.  The result?  A softer, fuzzier presentation of the high frequencies.  Better to some than hearing a sharper, more precise rendition, especially with the typical CD source.  HOWEVER, as a drummer, I've not yet heard a soft dome tweeter that faithfully reproduces the sound of a cymbal.  It always sounds softer, less gritty (yes, cymbals are gritty sounding), less realistic.  I haven't heard every tweeter, but the Morels I used for a project were very pleasant and most wouldn't notice their errors of subtraction, but I do.  To each, his own.  But, I suggest that people who think metal domes "shriek" haven't heard a good implementation of one.  The amazingly cheap tweeter that NHT has co-developed with Tonegan, I suggest, wouldn't allow you to tell it's a metal dome except from looking at it and except, maybe, that the cymbals sound so good

NHT Xd - Gotta hear it, it will toss out all your assumptions about metal.  S&V gave it a review this month, but it's funny because Tom Nousaine is an idiot when it comes to measuring things.  His technique sucks and it shows in everything he measures.  I guess he's never noticed that everything he measures has the same measurement signature.  In any case, it's very smooth, not fatiguing, despite the metal tweeter, despite the metal midrange, despite digital amplification, all stuff that has a bad rep for being bright.  It's all about implementation, folks.  Now, they aren't *flattering* to a bad recording like a softer speaker might be.  The technology, be it DEQX or a competitor, to do what NHT did is going to be everywhere and cheap in 5 years.  And speakers will increasingly look like Xd - lots of metal drivers in small, low diffraction baffles.  Xd is expensive for most people, but it kicks the living hell out of traditional $20,000 speakers attached to $40K in electronics, cabling, etc for 1/10th price.  

Back to your regularly scheduled programming.

[jackman]

Doug!  If you stay out of politics, you almost sound like know about what you're speaking

Actually, I'd rather comment on a few things:

Cone dampening - If you try to delete the cone resonance of a metal driver, you add mass,  it's largely going to be futile, it drives the resonance and the FR downward and know you have a small driver that has the characteristics of a large driver, but can't move air.  On the other hand, let it ring, keep it as light as possible, then cut it off sharply enough and  ...

John,

Thanks for the commentary but it's uncool to post a commercial for your speakers in another manufacturer's circle.  In fairness, Dave should edit your last paragraph.  I'm not big on rules but this one seems to make sense.  

Cheers,

Jack

[John Ashman]

He can edit if he wants, I don't care, the point wasn't about Xd, but Stuart mentioned it above and the point was that very steep crossovers can really allow metals to avoid ringing and therefore not be fatiguing.  You could do the same with DEQX and an 1801.  It's just inevitable that this is the direction speakers are going - steep crossovers, rigid drivers.  Xd is just proof of concept, that's all.  Besides, Dave's stuff and Xd are in different price classes.

[David Ellis]

Yeah,  

I really don't mind the input.  I obviously agree in the realm of compromises that soft cones and shallow crossovers are inferior to stiff cones and steep crossovers.  Although, there will always remain a group of folks on the other side "of the fence" on this issue.  This is perfectly fine.  Heck, I like the sound of paper cone drivers for some program material too.

I must agree that in 5-10 years the proliferation of digital correction, and digital noise will imbue the hifi world.  I suppose it'll happen similar to the advent of the CD player.  Certainly the early CD players weren't well received.  Nowdays, everyone simply must have a CD player. They have indeed became significantly better over time, and for most folks sound better than a record player/turntable.  However, there are significant differences among CD players under the hood.  Not all are created equally.  I am sure the same is true, and will continue true for digital processors  like DEQX.

I do, have a question for John.

I am really not sure who you are, but it seems you are very well read and very familiar with the NHT products.  I must admit being very unfamiliar with their products and only slightly familiar with digital crossovers.  However, given that you appear to have some degree of experience in hifi, I wonder if you might comment on something.  Have you any experience with Accuton drivers?

It appears the drivers in those NHT speakers are made in China/Tiawan, but I can't be certain.  Chinese drivers are much better than in the past, but to my ears still don't compare to the better drivers made in Europe.  Most recently, I experimented with the Accuton C95 and the Hiquphon OW1.  I managed a fairly good crossover before "toasting" my CLIO jig, and the results are extremely surprising.  The Accuton C95 driver is dead neutral, and very clean.  I am not finished with my work yet, but am curious if you have any backround experience.

Back to the proliferation of digital crossovers.... My hunch is that in 5-10 years the very best systems will have the very best components under the hood of the very best CD players, Speakers, Amps, and Digital correction devices.  Eventually I will have to learn about the latter.

[John Ashman]

I *wish* I was more familiar with the Accuton drivers.  They *look* impressive and the ringing looks more benign than metal.  I particularly like the tweeter and 2" upper mid.  It looks like you could make a passive speaker that has incredible detail, but still retain a smooth sound.  Costly, but not *that* bad. I'm surprised more companies aren't using them.  They appear to be tremendously accurate.  I'm tempted to build a DEQX speaker

[David Ellis]

When measured, the Accuton C95 nasty response bubble around 4.2khz is darn near on par with the SEAS W18 drivers.  However, there is something else happening here.  I really don't know what the issue IS, but when my CLIO jig is working, it will be explored further.

I am not surprised at the very small quantity of Accuton drivers in the hifi marketplace.  They are expensive - very expensive.  Given the quantity of production for hifi speakers and the necessary profit margins, using Accuton is a very questionable propositition.  The same is true with SEAS Excel series drivers on a lesser scale.  At wholesale prurchasing quantity it makes much more sense to use a $10 Chinese driver than a $150 Accuton driver.  

Further, when I attend the symphony, there are many empty seats.  It's smarter for a real money making company to spend more on a bunch of "features" that appeal to a consumer that has a keen eye, than spend money on simple things like drivers that appeal to a customer that has good ears.  After all, aren't all drivers made the same??? This is a sad progression, but one that I believe will be increasinly true.  The further consumers get from live unamplified music, the further consumers will get from discerning good quality hifi.  At this point, the techno-geek consumers of generation next will be far more into "features" than quality.

[John Ashman]

Hi David,
      i have to disagree with you a bit.  Sure, if you want to make cheap speakers, $10 drivers make sense.  But there are dozens and dozens of companies doing this.  And, to be honest, companies that can build these buy the hundreds or thousands will always do it better, cheaper, faster.  If you want to build speakers for the top 1% of the population that really cares, then you buy the Accutons and match them with the best enclosure and cabinetry you can.  

Besides, most of the cost of a speaker is the cabinet.  So, look at $10K and up speakers - it's all cabinet with maybe $250-$500 per speaker in drivers.  Maybe.  There are $50K/pr speakers that have probably $750 of the cost in the drivers.  So, you build a good, solid (but not *overbuilt) cabinet, spend a little more on the crossover and buy the best drivers available.  That's what I'd do.  

One thing I've learned from DEQX - the drivers matter far more than people know.  The more rigid they are, the more detailed and lower in distortion they are.  Real resolution.  Not faked, like most companies with resonant drivers or overdone upper midrange.  Let's face it, you can't get that with paper or poly.  And look at the cost of a Focal speaker.  If you could budget $500/pr for drivers and <$500/pr for cabinets, crossovers, misc, and build a high-end monitor speaker that sells for $2K-$3K/pr, you're building something WAY better than anyone else at that price range.

[David Ellis]

I think... we generally agree.  My assertion regarding the $10 drivers directed towards sensible accounting practice in business and the necessary profit margins.  After looking under the hood of a few speakers, and some personal knowledge of the drivers available... I believe the propensity of speakers around $1000 use $10 drivers (quantity cost).  This certainly results in a speaker that won't compete with a good DIY unit using better drivers.

The general gate for purchasing any driver in quantity is spending $$.  If you are willing to spend $5k - $10k per driver, you will be able to get them directly from the manufacturer wholesale.   This might infer purchasing 1000 $10 drivers, or 100 $100  drivers.

I found this stement very encouraging:

So, you build a good, solid (but not *overbuilt) cabinet, spend a little more on the crossover and buy the best drivers available. That's what I'd do.

     Basically, thats... what I do.    

The more rigid they are, the more detailed and lower in distortion they are. Real resolution. Not faked, like most companies with resonant drivers or overdone upper midrange.

I am not sure what you are currently using for drivers, but... some W18 drivers would work dandy IMO.  If you are able to splurge, some Accuton drivers might really be the ticket.  My first impression is darn positive.

Dave

[Rocket]

Hi Dave,

I thought i'd add my support for accuton drivers.  I've heard a number of speaker designs using these drivers which include their tweeters (a little too clinical for my tastes, i much prefer the raven tweeter), midrange and mid/bass drivers.  Imo they are the best that i have heard.  I haven't heard the seas line of speakers and cannot make any judgements about them but have extensively heard the focal and phl ranges.

At the moment i am building a diy speaker using raven 2 ribbon tweeter and 2 x phl mid/bass drivers.  I'm aware that you're not a fan of the phl drivers but i have heard them in a similiar design and thought i'd give them a try.

Anyway hope you don't mind my comments.

Regards

Rod

[David Ellis]

Anyway hope you don't mind my comments.

Your comments are very welcome.  

I must admit only hearing 1 pair of Accuton tweeters a few years ago in a lumenwhite speaker.  The system seemed a bit awry, so this wasn't a fair sample.  

The Raven tweeters... oh yes, they are very good.  

I must admit that while I can hear differences in the very best tweeters that I could easily live with any one of them.  The Revelator, Esotar, Raven, Hiq, Arum Cantus... are all dandy tweeters.  

I have only heard 1 PHL implementation, and was honestly not very impressed.  I am sure it wasn't the designer.  Maybe there are only a few "bad eggs" in the PHL line-up and I managed to audition one of them.  Certainly not all SEAS drivers are "usable".  I had some older 17cm poly cone drivers... ish!