Hard Audio - Ceramic Speakers

Are the Accuton ceramic midrange drivers pure ceramic or are they sandwich type?

I found this paper regarding Harman's CMMD drivers that were used in the Infinity line for quite a while:  https://www.excelia-hifi.cz/infinity/data/ceramic-metal-matrix-diaphragms.pdf

The new DCC cones in the Revel Be speakers reportedly take the CMMD design and improve upon it.  

@erik_squires 

Yes, I believe the coating is Aluminum Oxide, which is a ceramic material.  I'm not sure how they apply it, or what the difference is with the new Revel drivers.  

The benefits of paper drivers and soft dome tweeters are that their breakup nodes aren't nearly as nasty as metal drivers.  The downside is that their breakup nodes occur at lower frequencies.  

Still, breakup nodes are only an issue if you're running drivers into the extremes of their range or using shallow slope crossovers.  If you're building a 2-way or 2.5 way speaker with a first order crossover, it's something you need to worry about.  If you're building a 3-way using 4th order crossovers you'll have a lot less to worry about with regard to breakup nodes, unless you just picked the completely wrong drivers for your project.

The great expense may be worth it for marketing purposes alone.  I’ve never heard the speaker, maybe the diamond midrange is something special, but the B&W diamond tweeters don’t sound any better than the beryllium domes or RAAL or Aurum Cantus ribbons, or Legacy AMTs I’ve heard IMO. 

Yikes, at $7,100/pair for the Seas or $3,700/pair for the Accutons, those had better be something amazing.  Given that most of us can't hear much beyond 14khz or so once we're nearing 40, I think I'll take a pass on those.

FWIW I did think the Accuton ceramic midrange sounded excellent on the Salk Song3As.  Salk is using another fancy midrange in the Song3 Encores, a magnesium cone with a bunch of holes drilled into it and some sort of (polymer I believe) backing made by Eton, which didn't sound bad, but the room those were in at Axpona wasn't set up as well as the room with the Song3As, so probably not a fair comparison.  

Dr. Toole has said that EQ can help for room effects, but it can't fix a poorly designed speaker.  Frequency response is important, but you can't just look at on-axis.  A smooth and predictable off-axis response that mirrors on on-axis response (though with a more downward slope as you move further off axis due to directivity of the tweeters) is just as important as a smooth on-axis response, and EQ often doesn't fix problems in off-axis response.  

So, proper EQ can help make a good speaker sound even better in a room, it can't fix a speaker with fundamental design flaws.

As far as the various levels of Revel speakers go, while all are designed to exhibit the best on and off-axis response as possible at their various price points, there are benefits moving up the line. 

Moving from Concerta2 to Performa3 (and now Performa3 Be) to Ultima2 you get greater bass extension, greater power handling, greater dynamic range capability, less dynamic compression, less distortion at extreme dynamic levels, etc (plus of course the intangibles like more nicely finished cabinets and such).

Playing material without much bass content at a lower volume the Concerta2 F35 should sound remarkably like the Ultima2 Salon2.   Change the material to something with deep bass content and a very wide dynamic range played at reference levels and the differences will become apparent.  

The new drivers in the Performa3 Be offer more dynamic headroom, lower distortion at extreme volume levels, and stronger motor structure/better cooling to decrease dynamic compression.