Hello @profiguy, I happened to be reading this article yesterday which may shed some light.
Vivid Technologies – Vivid Audio
As I understand it, Laurence Dickie was the B&W engineer (responsible for the nautilus), who then went on to work at Vivid. It’s possible he used some of the the same techniques at B&W.
Vivid Technologies – Vivid Audio
As I understand it, Laurence Dickie was the B&W engineer (responsible for the nautilus), who then went on to work at Vivid. It’s possible he used some of the the same techniques at B&W.
I know I can't hear the 25k break up of a typical metal dome consciously but after a while I still feel the need to turn them down or even off.
I have a pair of tweeter from Tangband 25-1744. Which claims a ceramic dome. But it is really is anodized aluminium. Anodized aluminium essentially oxideses the a thick layer of aluminium (up to a few micrometers) essentially that layer is a ceramic layer. I found it to be a very pleasant and polite tweeter. The reviews for it lists it as a very polite driver. The layer increases the stiffness multifold. I wonder if that is what that makes it polite, a super stiff dome. For all you know the B+W domes might have been anodized as well. You won't be able to tell.
Oon
Oon
Thats very interesting and I can see the similarities in design philosophy.
I'm working on getting some measurements posted on the dm580s to possibly shed some light on the whole issue. It looks like I've ruffled some feathers out there regarding the hard vs soft dome debate. I know someone who may lend me a 50kHz capable measurement mic to get some good data. Fingers crossed...
In all sincerety, I've come across many audiophiles who love some of the most fatiquing sounding speakers I've ever heard. Most horn loaded speakers and some planars also fall into this category. Planar drivers are not immune to HF breakup and distortion issues either, although the HF peak is typically not as high in Q as the ringing present in some titanium or ceramic dome designs. Several aluminum and magnesium cone drivers also have bad breakup modes which can be heard even with a low and steep enough LP filter, which in theory should keep the cone breakul from being excited. I believe that even though the driver's input frequency range is outside of the cone's breakup frequency, outside mechanical vibration can still excite this ringing if it's high enough in level, sort of like the acoustical feedback you get when getting to close to a speaker with a guitar.
Also, I have never heard a decent sounding 2 way with a 1 inch dome that is crossed over lower than approximately 2.5K. While this has nothing to do with ultrasonic breakup, it still plays into the overall distortion performance of the speaker itself. IMD is a serious problem with larger 2 way designs that cross the HF driver low for the sake of avoiding the LF driver's cone breakup point and beaming. What you are left with then is a speaker that may sound clean and pleasant maybe up to 90-95 dB but falls apart with dynamic peaks and gets hard to listen too if asked to play reasonably louder. For those of you who think 100 dB is more than enough, guess again - even with classical music you need at least mid 100 dB capability to somewhat faithfully reproduce its peaks and that is with some recording compression. There have been studies done on this claiming you actually need closer to 120 dB capability to accurately reproduce uncompressed orchestral music at normal audience listening distance. To put it into perspective, a lousy little triangle is capable of almost 118 dB at arm's length when played normally! No, I'm dead serious and not joking. That folded piece of steel is extremely hard to record and reproduce, especially all of its overtones, some of which are higher in level than the audible frequencies and can go past 100 kHz!
As a speaker designer, I've tried every trick in the book to get around the problem of lower xover points while having decent dynamic capabilities. There are a few 25-30ish mm HF drivers which break the rule (ie. Morel CAT378, Scanspeak D2905-9500, above mentioned B&W dome) but eventually the laws of physics always prevail. If the design calls for a large 2 way, I'll always choose a larger dome like the Audax TW034 or Seas T35-C002, even though these drivers don't have as much HF extension as a smaller dome tweeter. I'd rather have better dynamic capability with lower distortion. A speaker that is capable of spl peaks under 100 dB is useless to me. The B&W DM580s are easily capable of playing to mid 100 dB comfortably over 45 Hz. I run out of cone excursion way before any thermal power handling issues kick in. There are many larger 3 way designs that can't keep up with these things. The tweeter is just simply amazing and probably one of the best 1 inch domes I've heard to date, dare I say at any price.
If its at lower listening levels (not factoring an excessively low crossover point), its likely due to the secondary effects of the HF ringing induced IMD. Some people are more sensitive to it than others and not all metal domes have it to the same extent. I have some Thiel/Seas metal domes that sound really good, but not as good as the B&Ws. In theory, beryllium domes should sound better than most other metal domes due to the inherit higher damping characteristics they have. I can't vouch for that not having heard any modern Be domes, only the ones in the Yamaha NS1000s which aren't bad.
I have never seen a published measurement of B&W speaker that is ruler flat from 2K to 15K. I wonder where I can find one.
Hello again @profiguy, for ultrasonics to have an audible effect, there needs to be an acoustic downmodulation process somewhere. This could happen if there is a non linearity - the question is, where?
This article may be of interest: Sound from ultrasound - Wikipedia
I’ve seen demos of this technology at an AES show - projected birds tweeting onto a wall.
According to the article, if the spl is very high, there can be a change in speed of sound in air, resulting in a nonlinearity. I didn’t read the full article, but the ultrasonic peak would have to be very high....
The effect would be measurable if you did a multi tone out of band test, though you might burn out the tweeter first ��
This article may be of interest: Sound from ultrasound - Wikipedia
I’ve seen demos of this technology at an AES show - projected birds tweeting onto a wall.
According to the article, if the spl is very high, there can be a change in speed of sound in air, resulting in a nonlinearity. I didn’t read the full article, but the ultrasonic peak would have to be very high....
The effect would be measurable if you did a multi tone out of band test, though you might burn out the tweeter first ��
And here are another couple of demodulation mechanisms: http://pub.dega-akustik.de/ICA2019/data/articles/000943.pdf
And
https://www.tinnitusjournal.com/articles/ultrasonic-hearing-in-humans-applications-for-tinnitus-treatment.pdf
So demodulation by the human body and the brain.
Kind of cool, in way.
And
https://www.tinnitusjournal.com/articles/ultrasonic-hearing-in-humans-applications-for-tinnitus-treatment.pdf
So demodulation by the human body and the brain.
Kind of cool, in way.
The other possibility is that you are hearing an interaction between the DAC and the tweeter.
There are some exotic DAC technologies that don’t filter out-of-band images so much. These might interact with nonlinearities in the tweeter itself, resulting in in-band components. Could this effect be worse with tweeters that have a high ultrasonic peak? Pure speculation, but this would be measurable through in-band tones.
Also class D amps have high frequency components, with varying degrees of filtering, depending on the technologies. I don’t know whether there have been studies of the impact on transducer nonlinearities.
There are some exotic DAC technologies that don’t filter out-of-band images so much. These might interact with nonlinearities in the tweeter itself, resulting in in-band components. Could this effect be worse with tweeters that have a high ultrasonic peak? Pure speculation, but this would be measurable through in-band tones.
Also class D amps have high frequency components, with varying degrees of filtering, depending on the technologies. I don’t know whether there have been studies of the impact on transducer nonlinearities.
Are you being sarcastic or serious?
I don't listen to sub par speakers and these B&Ws are the only non self built ones I possess. They are extremely flat in the midrange to top end. There are a few speakers that actually measure flat in an average listening room without correction. Why the hate for B&W? If some of their stuff is good enough for EMI studios and the BBC then why should they be talked down upon? I don't listen to crap speakers and these surely don't fall into that category.
How do you manage to measure them flat, while all others fail? Well to be fair, in previous millenium B&Ws were pretty good
Some links to collections of measurements
SoundStageNetwork.com | SoundStage.com - Loudspeakers
Floor Loudspeaker Reviews | Stereophile.com
Lautsprecher Messungen Archive - FIDELITY online
A collection of loudspeakers measurements
Some links to collections of measurements
SoundStageNetwork.com | SoundStage.com - Loudspeakers
Floor Loudspeaker Reviews | Stereophile.com
Lautsprecher Messungen Archive - FIDELITY online
A collection of loudspeakers measurements
The crossovees are no longer stock which changed the FR for the better. I modified them specifically for better linearity. They sounded much more forward before which I detest and I can understand why people don't like the B&W signature sound, however not all of their speakers sound that way. The crossover in stock form had electrolytics in the HP section which is a no go for me under any circumstance. So all of those changes to the crossover transformed the performance by a factor of 10 and i ended up with a speaker that was surprisingly good.
Yes,I agree that the tweeter drivers of B&W are super good and linear - measured in nearfield and installed properly with good crossover.
A good example here www.audioexcite.com >> Bowers & Wilkins 685 review part 2 Smooth curves, but not so good timing/phase and response match making summed on-ax response drop between 6,5 - 9kHz.
But the problem started when B&W started to put the tweeter on top of the box! This makes huge interferences!
A good example here www.audioexcite.com >> Bowers & Wilkins 685 review part 2 Smooth curves, but not so good timing/phase and response match making summed on-ax response drop between 6,5 - 9kHz.
But the problem started when B&W started to put the tweeter on top of the box! This makes huge interferences!
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I've been very happy with a pair of SEAS H400 aluminum domes for 32 years. They have a vented magnet and a rear chamber. They're crossed over just below 2k and are mated to a Focal 5K013L. Many metal domes sound a bit harsh and irritating to me, but these have always sounded sweet and airy with gentle detail to me.
Are the B&W drivers proprietarily made for B&W, or were they an off the shelf item?
Are the B&W drivers proprietarily made for B&W, or were they an off the shelf item?
The B&W drivers are proprietary, but I assume Dr. Kurt Muller GmbH is the manufacturer of the aluminium domes.
The exact model number is TM303 for the DM 500 series 8 ohm tweeter. The 4 ohm version is ZZ5460. They have ferrofluid as well. I believe this helps with damping at resonance. They must use a low viscosity FF because it doesn't appear to hurt low level detail.
The dome does look like a Dr Mueller sourced piece. They do that catenary profile on some tweeters ie. audax, etc, but this one looks to be spherical.
The dome does look like a Dr Mueller sourced piece. They do that catenary profile on some tweeters ie. audax, etc, but this one looks to be spherical.