New ceramic drivers from SB Acoustics

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andy2

Member
Joined 2004
scudinc said:
"[He] treats objects like women, man!"



One is a swimsuit model, the other is an Emmy, Golden Globe, and Oscar-winning actress/enema enthusiast. What does that inane comparison accomplish besides evincing your misogynistic bigotry? You're explicitly saying that you think women's accomplishments are less relevant to their worth than their outward appearance. I can picture you idly fingering the reflex port on your speaker, whispering to it, “I'll show you where they have some nice furniture.”


Anyway, to get back on topic, I'd really like to see someone compare a few samples of these directly against the NBAC line to see if that superficial layer of ceramic accomplishes anything.
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Well I am what I am ... what can I do?
 
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andy2

Member
Joined 2004
eriksquires said:
Andy,

I can totally see how we get very excited over first giving life to a long project like this. But I'm still kind of scratching my head over how many measurements you took, and then stopped relying on best practices.

Just based on the transfer function, I would worry you aren't doing enough to protect the tweeter. So, on a reliability and power handling basis alone I have to question your design.

If your FR measurements are correct, I know I would find the speakers a little bright and discontinuous, on the other hand, the shape lends itself pretty nicely to lower volume listening. You can keep the shape of the curve while improving power handling and off-axis response. Personally, I really think you are doing those tweeters a disservice. They sound even better than this.

Make yourself happy, but I encourage you to keep an open mind and to continue discovering.

Best,

E
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Tweeters are fine. Protection is yourself.
 
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scudinc

Member
Joined 2005
ScottG said:
Is it truly a superfical layer of oxide?

How about the honeycomb structure underneath?
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That's the CRC line. The patent that Harman filed for CMMD describes
…a composite material formed of two layers of ceramic material separated by a light metal substrate and where the core is formed by stamping a sheet of standard gauge aluminum to form a speaker core and then deep anodizing the core to obtain a ceramic layer of alumina on each surface (Al2O3) that is at least about 1 mil. thick.
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We know that SB has supplied these drivers for Harman's Revel brand. It's maybe a slight exaggeration to describe a 0.001" coating as "superficial", but the patent specifies that the diaphragm is about 80-86% metal.
 
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Mario Pankov

Member
Joined 2007
scudinc said:
see if that superficial layer of ceramic accomplishes anything.
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I did a photoshop merge of the responses of some of the ceramic and aluminium mudwoofers and effect was barely noticeable. However, look up the tweeter range - the SB26ADC (aluminium) has a modest resonance at 27Khz. Its twin brother with ceramic/aluminium dome (SB26CDC) has a much weaker resonance and it is at 34Khz. MMs is identical as is construction and motor, only dome is different (and maybe surround but I doubt it). Indeed, it looks like a killer tweeter.

These are notwhere near as ceramic as the Accuton (Al2O3 deposited over some plastic) or the TLabs (sintered Al2O3) but this seems to have an effect and they don`t come with a mortgage.
 
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system7

system7

Member
Joined 2008
I was trying to remember where I had seen this ceramic idea before. Here it is:

When I founded Sonics by Joachim Gerhard in 2004, I had a new opportunity to try metal as a membrane material again. SEAS makes woofers and midranges from much thinner and lighter aluminum and the cones were shaped in such a way that stiffness was at its maximum without causing the drivers to break up horribly.

I used a conical profile at the time, as geometrically a cone has the best stiffness of all shapes. The angle of the cone is designed in such a way that the sound that emerges around the voice coil reaches the front baffle at the exactly the same time that it takes the sound to travel through the cone so that theoretically we have a flat wave that is in-phase over the designed frequency spectrum.

This is possible because the speed of sound in solid material is faster then it is traveling in air, and by the time the sound from the inner part of the cone near the voice coil and the sound from the outer part of the cone travel through the cone, they get to your ears at the same time. We only have to know the Young’s Modulus (a measure of the stiffness of a material) of the membrane material and off we go…theoretically!

For even greater stiffness, these aluminum membranes are deep anodized on both sides. Aluminum oxide is the same material from which gemstones like sapphire and ruby are made. It is the second-hardest material on earth after diamond. With this anodizing technique, a very stiff and light membrane is produced (even better then carbon fiber in woven or nanotube form).
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That was Joachim Gerhard talking about his Sonics Anima speaker. No great secret it used an anodised SEAS 5" midbass that he helped develop.

Looks like SB are doing the same thing: SB Acoustics :: 5” SB15CAC30-8

Must work even better on light tweeter domes: SB Acoustics :: SB26CDC-C000-4
 
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Brumel

Member
Joined 2018
I have made an order of the 6" CAC 8ohm from Intertechnik in Germany. Im going to pair them up with the CDC tweeter. The geometrical reinforcements made on the cone is the reason why I bought it. It surely must mean a simple filtering is possible.

I already have the SB 17 CRC. Maybe I put them in the same box. But since my baffle can't house them booth I must put the one rear facing. Pity there is no carbon tweeter around that I can think of besides diamond.
Davis Acoustics makes a graphite series cone tweeter that matches the color of the CRC.
 
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digitalthor

Member
Joined 2018
system7 said:
Nah, he's been there, done that.

An interest in an 85dB 4" metal cone suggests a midrange to me. :D

I have to admit that the word ceramic is not exciting me much now. Why? Well, I just compared the 5" NAC ($72 Aluminium) cone with the 5" CAC (Ceramic) cone. Both got 5 ribs.

5" SB15NAC30-8 :: SB Acoustics
SB Acoustics :: 5” SB15CAC30-8

I can't see much difference! :confused:
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I know it has been a while... but could you please post the results again :)
 
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42476

Disabled Account
Joined 2019
Bill poster said:
Has anyone made a test comparison ? Outside of manufacturer
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I have 3 SB model 6 inch drivers. The SB17CAC35-4, the Satori MW16PNW-4 (white cone) and the Satori MR16P-4 (midrange). I haven't done any measurements or scientific testing, just listening tests in various types of enclosures. The CAC has the edge for deeper and stronger bass but the upper range isn't nearly as clean, accurate or "musical" as the 2 Satoris are (no surprise really). If you stay above 100Hz, the MR16P sounds the best overall compared to the other 2 models. It has a flatter and more extended response than MW16P. The MW16P gets the prize for a 2-way when bass below 100Hz IS required. The CAC gets the prize if it is used in a 3-way (crossed at 600Hz or below). Most people wouldn't consider a 6 inch 3-way but I'm thinking 2 of the 17CAC 8 Ohm drivers in parallel coupled with a good mid and good tweeter would make a great small and slim, 3-way tower.

These are just my opinions but based on literally thousands of hours of critical listening "tests". Again, no formal testing or measuring by me except test tones, sweeps, etc. (no microphones or test equipment; just my 2 ears) and well known recordings.

FWIW...
 
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bentoronto

Member
Joined 2008
oldspkrguy said:
...These are just my opinions but based on literally thousands of hours of critical listening "tests". Again, no formal testing or measuring by me except test tones, sweeps, etc. (no microphones or test equipment; just my 2 ears) and well known recordings.

FWIW...
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Modestly put.

But for want of a few minutes effort and no money for the REW honourware software, you could provide us with very helpful data using your laptop mic and REW. Best to be able to compare two speakers/drivers but still informative to plot whatever you have connected.


Well, if you've had 10,000 reasons not to get off your duff and be brave and test with REW, now you have only 9,999:

Mic versus mic: too bad for casual builders - diyAudio

B.
 
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4

42476

Disabled Account
Joined 2019
bentoronto said:
Modestly put.

But for want of a few minutes effort and no money for the REW honourware software, you could provide us with very helpful data using your laptop mic and REW. Best to be able to compare two speakers/drivers but still informative to plot whatever you have connected.


Well, if you've had 10,000 reasons not to get off your duff and be brave and test with REW, now you have only 9,999:

Mic versus mic: too bad for casual builders - diyAudio

B.
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I was not aware of this software; is it any good? Many years ago; decades actually; I had a large house with a very nice, large listening space. At that time; I had a calibrated microphone with pre-amp and could borrow from work $100,000 spectrum analyzers, O'scopes, frequency synthesizers, and so on. I thought about investing in some decent equipment but decided against. So I guess these days microphones and software are very cheap or even free.

Let's start a new thing here; move elsewhere or point me in the right direction. What are some of the best calibrated microphones/pre-amps/equipment/software, etc. available for acoustics, speaker and room testing? At price ranges $100 and below. I would want something fairly accurate; maybe +/- a few tenths of a dB and +/- a few Hertz. Not professional certainly but a decent suite that is reasonably accurate. I am in a much smaller house with a much smaller listening space these days so chirps, gating, etc. would be necessary (or anything else to minimize or eliminate room modes, etc.).

Thanks for the heads up; I obviously haven't kept up (but never really needed to since it is all a hobby now for just me)...
 
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