SS D3004/6640-00 Beryllium Tests?

[villastrangiato]

I've noticed the SS beryllium version of the one inch air circ tweeter is starting to find its way into some high end speakers at this year's CES - anyone get a chance to hear or test these yet? The off axis response for some reason looks like crap - especially given the crazy pricetag.....

[Face]

http://www.htguide.com/forum/showthread.php4?p=484866&highlight=6640#post484866

[villastrangiato]

Thanks!

The datasheet on Madisound talks about "outstanding dispersion" but from the looks of the response plot - it doesn't look much better than any other decent 1" ring radiator - a "lowly" $50 SB comes to mind....

Maybe it's an optical illusion, but the beryllium version's dome appears to be more flat than the D3004/6600-00 textile unit. Perhaps this would explain the serious drop off at 60 degrees where the regular unit's response stays pretty respectable well past 10khz. I've read in a number of places where beryllium is hard to work with and that only a handful of facilities around the world are capable of producing the thin toxic wafers. I wonder what obstacles might have existed in forcing SS to produce a flatter dome - leaving the door wide open for significant beaming and cancellations well off axis.

[dlr]

Thanks!

The datasheet on Madisound talks about "outstanding dispersion" but from the looks of the response plot - it doesn't look much better than any other decent 1" ring radiator - a "lowly" $50 SB comes to mind....

Maybe it's an optical illusion, but the beryllium version's dome appears to be more flat than the D3004/6600-00 textile unit. Perhaps this would explain the serious drop off at 60 degrees where the regular unit's response stays pretty respectable well past 10khz. I've read in a number of places where beryllium is hard to work with and that only a handful of facilities around the world are capable of producing the thin toxic wafers. I wonder what obstacles might have existed in forcing SS to produce a flatter dome - leaving the door wide open for significant beaming and cancellations well off axis.

I suspect that they've simply elected a certain set of tradeoffs. The more shallow the dome, the higher the frequency limit on-axis that for a hard dome is almost purely a function of geometry and phase delta from tip to former attachment ring. The tradeoff is that off-axis, the phase delta is higher at any given angle for a more shallow dome vs. a deeper dome.

It's not necessarily a bad idea to have a bit more rolloff. This may reduce the "illumination" of the baffle edge, reducing baffle edge diffraction. This is evident in the ring radiators.

Dave

[JonMarsh]

As I posted on the Ardent thread, I think the reason to consider the 6640 lies not with "wide dispersion", which is an oxymoron for a 1" dome with true pistonic behavior and no phase shield, but having a minimal resonance and distortion amplification factor compared with aluminum or titanium domes- or even ceramic domes. In that regard, the part appears superb. I'm hoping for a clean, detailed presentation, hopefully largely free of sins of commission. We'll see how that turns out- I wish I could just jump on that this weekend, with the continued Ardent testing, but finishing the first set of Modula MT's and completing a modification with new SPDIF output functionality on a Pioneer DV79AVi have precedence. I get nervous leaving an complicated piece of electronics sitting around in pieces.

[villastrangiato]

I was assuming SS was sourcing it's beryllium wafers from the Brush Wellman plant in Ohio - using the heating and forging process like Focal to produce the domes of their beryllium tweeter. Therefore, I figured that when pressing the flat metal wafers into tighter radius domes (less shallow), the material underwent more stretching - resulting in irregularities in the thickness profile that might lead to stress concentrations and a higher tendency for breakup modes or worse yet - outright failure. So it never occurred to me that a shallower dome would be a matter of choice - but more of a manufacturing constraint in the forging process. If the domes were made like JBL used to - vapor deposition of titanium or like TAD apparently still does with beryllium, then that issue would seem to go away - but then I'm sure other issues would present themselves. In any case, it never occurred to me that manufacturers would want to limit 60 degree off axis performance intentionally to reduce baffle interference - that's an interesting perspective and on some levels - makes perfect sense.

I discovered this article a while back - it seemed pretty informative.

https://www.goodsoundclub.com/Docs/Truth_beryllium_diaphragms.doc

[villastrangiato]

As I posted on the Ardent thread, I think the reason to consider the 6640 lies not with "wide dispersion", which is an oxymoron for a 1" dome with true pistonic behavior and no phase shield, but having a minimal resonance and distortion amplification factor compared with aluminum or titanium domes- or even ceramic domes. In that regard, the part appears superb. I'm hoping for a clean, detailed presentation, hopefully largely free of sins of commission.

I should qualify my less than flattering appraisal of the 6640 - the dispersion it does exhibit is quite good overall - somewhat off though from the textile version costing less than half. I was a little disappointed in that - but who am I kidding - I'd love to have a driver like this that could handle gobs of high frequency power in stride. Clearly, you do get something for the extra $280 - maybe not everything you could ever want but close enough. I should also acknowledge that I come from the John Krutke "el cheapo" school of transducer appreciation........

[ThomasW]

I discovered this article a while back - it seemed pretty informative.

Steve Mowry spammed most forums including HT-Guide several months ago when he went on his little self serving rampage.

For obvious reasons we won't be revisiting this topic again..

[villastrangiato]

Steve Mowry spammed most forums including HT-Guide several months ago when he went on his little self serving rampage.

For obvious reasons we won't be revisiting this topic again..

I didn't search the boards before posting his shpeal.....clearly, it is self serving but there is some useful information presented - I'm sure most folks with common sense will have the means to separate the wheat from the chaffe...

Often when one starts a thread, the ensuing discussion, interaction, and search for greater understanding takes us to places we didn't anticipate at the outset. I had no intention of using this thread as an opportunity to rehash something - much less grandstand on anyone's behalf. I've always thought that cutting edge metallurgical processes were an important and exciting aspect of transducer development - Mowry's article, salesmanship notwithstanding, is a peek into that closely guarded, sometimes very secretive world.

[Winter]

Steve Mowry's excellent article brought to the public attention information on beryllium an its application in audio tranducers. Very few other persons would have been technically capable of writing the article. Making the public aware of deceptive technical claims and advertising is a public service. His biggest hurdle is that the offending companies, Usher and Tang Band, have produced numerous good products in the past and have loyal customers who desire to minimize the transgression.

[villastrangiato]

Steve Mowry's excellent article brought to the public attention information on beryllium an its application in audio tranducers. Very few other persons would have been technically capable of writing the article. Making the public aware of deceptive technical claims and advertising is a public service. His biggest hurdle is that the offending companies, Usher and Tang Band, have produced numerous good products in the past and have loyal customers who desire to minimize the transgression.

I'm not sure who is or isn't capable of expounding on technical details involving the use of beryllium transducers. I did happen to read another very informative article detailing the forging process at Focal - maybe it was on their website, I'm not sure - my memory fails me. Regardless, for me, Mowry's focus on playing the "detective" role doesn't detract from the technical information presented on the different manufacturing methods - vapor deposition vs. forging. People can read his rather slanted rantings about corporate integrity or lack thereof and draw their own conclusions. Frankly, I buy Dayton and Usher drivers because they offer a price/performance ratio that puts "handmade" Scandinavian products to shame. And if you read the article carefully - along with other press reports issued directly by Usher - it is very obvious the company acted swiftly and responsibly in dealing with questionable suppliers. As Thomas suggested, I don't think it is worthwhile to belabor the point - the focus here, in this particular thread, is the technical means by which beryllium transducers are manufactured and how that bears on design/performance limitations. I would appreciate it if any further discussions on this thread be confined to technical rather than political considerations. Thanks.

[JonMarsh]

Steve Mowry's excellent article brought to the public attention information on beryllium an its application in audio tranducers. Very few other persons would have been technically capable of writing the article. Making the public aware of deceptive technical claims and advertising is a public service. His biggest hurdle is that the offending companies, Usher and Tang Band, have produced numerous good products in the past and have loyal customers who desire to minimize the transgression.

Quite true... what do you do when "good" companies go bad... and go to lengths to deny it and cover up? Both Usher and TB did, by any objective standard.

OTOH, Steve also pursued his goals in a manner rather lacking in evenhandedness. Guess that's what happens when people get worked up and perhaps a bit narrowly focussed.

I should also acknowledge that I come from the John Krutke "el cheapo" school of transducer appreciation........

I can certainly appreciate and respect that- which is why I was a big fan of the D26NC55, and the T25CF001 - both drivers with low sins of commission, and very neutral in their presentation.

OTOH, I've got a pair of Millenium Excels on hand that have been tested, and only tested briefly in one project; consistency of SPL behavior seems a problem with that product for some reason- either that, or bad luck on my part.

An interesting thread would be everyone nominating their favorite budget tweeter and why, and their favorite expensive tweeter that they've actually used, and why, and if there is any intersect in the middle providing a balance of both (where I would nominate the SS D2608/9130, which I've just about decided I prefer regardless of cost to the D3004/6620001). No benchracing of parts you haven't bought, tested, and used in an actual design, of course.

[jackies]

Gotta bump this thread!
Anybody got personal experiences and comments on sound of the D3004/6640-00?
Besides it being ridiculously expensive - one can get a pair of NS-1000M for that money, right?

[Face]

Ask Rick Craig: http://www.audiocircle.com/index.php?topic=91622.0

[JonMarsh]

The more I listen to it, the better I like it. But you're looking for other opinions, of course. The best way I can describe it, is that it has a very fine grained presentation with a lot of harmonic integrity on cymbals and percussion of all types, without putting any spitty edge on things, as even the cloth 6620-01 does a bit at times. More coherent and real sounding. mind you, I'm sure that to get the best in this frequency range you need good source components and source material- otherwise GIGO results.

At the moment I'm listening to the 24/96 version of "Raising Sand" (Robert Plant and Alison Krause), which I'm really enjoying on the Ardent's with the 6640- open and detailed, stuff floating in space at times, but not edgy, and good imaging. This is with an Aragon 8008 BB X3 amplifier, direct driven by a Metric Halo LIO-8 Firewire audio interface, from a Mac Mini running Fidelia Advanced as the player. Fidelia is operating in memory mode, and with resampling all tracks to 24/176.4, which is the fixed frequency I'm running the DAC at. Digital filtering is setup for minimum phase, not linear phase- more like an Ayre QB-9 or the current Meridian gear.

The 6640 does NOT have wide dispersion above 14 kHz; it's very much a hard dome; but the reproduction is quite satisfying to me- no artificial sheen, but very open and detailed. I do use RealTrap RFZ baffles in room to kill early arrival comb filtering from slap echo- no point spending big money on tweeters or the overall playback system and not paying attention to the room- though I've seen that often, with predictable results.

For the record, I prefer the D3004-6600 over the more expensive D3004/6620-01.

~Jon

[jackies]

Hey Jon, thanks for the detailed answer!
Preferences in tweeter sound is of course, a matter of taste.
I seem to prefer hard domes, as I recently discovered. I knew I liked the sound of JBL Ti tweeters, even though they have good amount of sheen and roll off rather early. I spent about a year listening to SS 6600 and MDT33, trying to decide which one I like more, and the answer was a resounding "NEITHER". I suddenly remembered that I had a pair of Accuton C12 on the shelf, I hooked them up and bingo! Although not perfect, I liked the sound much more.
So I was thinking that maybe this Berillum dome could be an "ultimate" hard dome?

[JonMarsh]

well, there are some similarities between the Accuton sound and the 6640- I'd rate the 6640 superior to the C12/C13 and C30-024, and pretty close to the custom Accuton diamond tweeter used in the Kharma Exquisite Mini, which I've listened to a lot at a friend's in Munich. (I don't have nearly the same amount of "ear time" with the Avalon Eidolon Diamond, for example, or the Isis- but they seem also to be representative of the best in hard dome tweeters.).

[benchtester]

For the record, I prefer the D3004-6600 over the more expensive D3004/6620-01.

~Jon

Since you have dipped your toe in the water. How would you rank the:

D3004-6640-00
D3004-6600
D2608/9130
D3004/6620-01

[JonMarsh]

well, you know, those tweeters cover quite a price range and intent... and any opinion from me is just an opinion- everyone has one of those. However, I do own and have worked with all of them, so I'm not just bench racing.

My least favorite of the lot is the D3004/6620-01. I'm not saying I can hear the peak in the top end; but there's something going on, I suspect, with the waveguide like baffle that gives it that peak and enhances the measured dispersion which nonetheless I don't like- and as the 2nd most expensive, for me, it falls out on the value proposition.

The D2608/9130 is my favorite tweeter under $100, and favorite so far for waveguides. Thanks for bringing your modified tweeter plate and waveguide and showing me how that goes together- I'm still trying to figure out how I'll get a tweeter plate actually machined that way with the resources I have (or rather, don't have!), but I do think what you've hit on is the way to go.

For a direct radiator setup the "standard" 6600 air circa is a nice part, but not inexpensive. Is it worth 2x the 9130? If you have to run with lower slopes or higher power, perhaps. When you measure the distortion in a real world system, they come out pretty close.

The D3004-6640 just has a characteristics that is open, detailed, not at all grainy gritty (if the source is good) that is hard to find, and similar to what I hear with the best of the Accuton tweeters. That doesn't mean it's something everyone will like. But in the Ardent's it's doing exactly what I was looking for- perhaps it's the apparent lack of resonance amplification of distortion products, not causing IM down in the audible range? I don't know... it does in the top end for me, what the best Accuton midranges do in the midrange- the C79 and the 173-T90. It's not cheap, but then look at how much you can spend on other parts of a system like this, or on a line array. I'd rather have (at this point) one really good $500 tweeter than 10 $50 tweeters.

Just my 0.02.

[jackies]

Just my 0.02.

Considering the price of the tweeter we are talking about, it's more like, $20!
:T
Thanks again for sharing your observations!
What I seem to like about JBL titanium tweeters, is the naturalness of tonal representation of cymbals. All other tweeters (silk domes, RAALs, Accutons to a lesser extent) turn cymbal sound into some sort of "white noise". If you know what I mean... They just don't sound like cymbals any more...
That's why I was thinking that maybe berillium domes, being metal domes, would be able to reproduce cymbals better than ceramic domes?

[JonMarsh]

Considering the price of the tweeter we are talking about, it's more like, $20!
:T
Thanks again for sharing your observations!
What I seem to like about JBL titanium tweeters, is the naturalness of tonal representation of cymbals. All other tweeters (silk domes, RAALs, Accutons to a lesser extent) turn cymbal sound into some sort of "white noise". If you know what I mean... They just don't sound like cymbals any more...
That's why I was thinking that maybe berillium domes, being metal domes, would be able to reproduce cymbals better than ceramic domes?

You've hit the nail exactly on the head- same thing with other brass or metal instruments- but also, the Beo SS tweeter doesn't put a spike or resonance anywhere in the HF spectrum (measurable or audible), so when a metal percussion like some types of gongs or other instruments should sound soft but metallic, it does. The best of the Accuton tweeters do that, too- even the old C23 is quite decent in that regard. No tizzz as from a soft dome.

[benchtester]

Jon - thanks for the write-up.

I still haven't heard my D2608/9130's under controlled conditions. The first set went to my audio friend. I hope to finish the second set this week and am looking forward to trying them out. (By the way my reference is the D3004/6600 in a homemade waveguide, which I am pretty happy with.)

You have peaked my interest in the 6640's. But, before I totally count out the soft domes, I will be trying them in an active system with tweeter-specific amplifiers.

[JonMarsh]

It will be interesting to see what you think of the 9130 versus the 6600 in a waveguide; in principle, the rising top end response of the 9130 results in a flatter response with less crossover work in the waveguide, as this area actually gets flattened out due to the dispersion enhancement of the waveguide.

I'm hoping to find out how the Ciare 320 work in the Jantzen waveguide before July is out, but the Ardent updates come first.

Also, my travel schedule/plan for work has ramped drastically in the last week; I'm flying to detroit on father's day (which rather PO'd me) and the following week to Raleigh, to interview some AE candidates, with visits now scheduled to Texas for HP, Dell, and others the second week of July, and more looming in the background. Ugh....

Plus another trip already planned in early August to Raleigh again- prime time for high temps!