Speakers using ceramic drivers....differences?

I have primarily VAC amplification.
I'm trying to determine the sonic differences in the most popular lines using ceramic drivers
(Kharma, LumenWhite, Avalon, Marten Design, Usher Audio, Venture Audio)
I tend to migrate to the sound of the Acuton midrange clarity and dynamics. I have heard Kharma and Lumen White, both excellent ; any experience out there with Usher Audio (significantly less expensive..AC-10/20) and Marten Design?
I have been fascinated with the new Marten Coltrane for some time. I checked the specifications and using a simple math formula the twin 9 inch woofers in the Marten are 509 square inch drive area compared to 530 square inch drive area for the Kharma Exquisite 1D's single 13 inch Nomex-Kevlar sandwich.

Factor in that the woofers in the Marten are by Accuton and made of the same ceramic as their 4 inch midrange, the Marten has the potential to produce faster more coherent integration between bass, mid bass and mid frequencies.

Both systems (Kharma Exquisite and Marten Coltrane) use Accuton diamond tweeter. The Kharma uses a 1 inch Accuton diamond and the Coltrane uses the 3/4 inch Accuton diamond.

Both systems claim bandwidth from 20 to 100,000K, plus or minus 2 DB. We all know specs mean nothing, so tomorrow night I (finally) get to hear a pair of Kharma Exquisite 1D's on a system with IDENTICAL components as mine. (Yes I'm partially responsible for that :^)

I plan to fly to California and listen to the Coltrane this summer if my work goes well. If I can't afford the trip I will have to wait for an audio show.

The main reason I am interested in the Coltrane is price. $50K is indeed expensive, but the Kharma is $120K, so if they are even close, it's no contest because of the price difference.

Last thing, the Coltrane's are 448 pounds lighter (per cabinet!!) Due to a new carbon fiber construction technique.

Perhaps the greater mass of the Kharma works an advantage and perhaps not. I plan on listening to both and try to dismiss the price difference when judging.
You like these drivers?
I have heard some of the, for want of a better word, exotica, but find myself gravitating back to the 'natural' products, except for my SL.
The magnesium drivers are very good, but have a 'sound' in some of the applications that I have heard.
I have heard excellent mids and highs from the diamond tweeter in the Kharma, Marten and Avalon Eidolon. The mids in the Kharma are very clean and disperse almost equal to Soundlab, so there are some things they do that are excellent.

My problem will be if they do great mids and highs but won't do bass. Overall tonal balance is as important as resolution to me. That's why I always defend Vandy's, they get the tonal balance right even though not the highest resolution speaker out there.

I will likely never part with my Soundlabs. Considering they have been my reference for 15 years. However, I always play "what if" and look at each new offering (especially cone speakers) as a potential replacement.

Thanks for your insight.

I too would be interested in your Kharma/Marten listening comparisons. I also am thinking about the Coltranes or Coltrane Altos. Any word on the significantly less expensive Usher AC-10/20's recently praised and honored by Soundstage for musicality and coherence (using 1" ceramic tweeter, 4" ceramic mid and 10" conventional woofer(s)...1 or 2 (AC-10/20)

We have the Marten Coltranes here and, as you suspected Albert, they have a very tight, top-to-bottom tonal and resolution consistancy, very similar to the Vandersteen in this respect (in particular the Vandy 5... my old 2ce, well, it did OK... :-) .

Compared to the Kharmas, the Martens are more real, neutral and detailed, not quite as easy to drive (though we run our Coltranes off the Kegon 22 watt SET monoblocks to good effect), slightly more musical, with deeper and more detailed bass, but without that oh so effusive midrange of the Kharmas.

The same comparison more or less goes for the Avalons as well, though the Avalons are much harder to drive than either the Marten or Kharma. The LumenWhites have just been updated, as I understand it. In the past they could be a little crispy and a little on the cool side at times.

I have heard good things about the Venture - but have not actually heard them myself.

We have at times seriously considered carrying all of the above speakers - they can all be made to make a very satisfying sound (some easier than others ;-)

As always, "Use the ears, Luke".

If any of you are ever up near Denver town, you are welcome to stop by and hear the Coltranes with your own ears. And Albert, I'm afraid you can only up here after our @#$%^ remodel is done :-) We would love to hear your impressions of the Edge 800 watts NL Reference 'pyramids' on the U1s, along with your impressions of the Martens.

Mike (Marten Design dealer)
Mike, that is tempting, I would love to hear the Coltrane. How many hours did it require to break in? Do they do true deep bass?

What sound pressure level can they reach before compression and /or distortion?

Do I understand from your comments about NL Reference on U-1's that you have a pair of the big Soundlabs in your demo room?
Hey Albert,

Breaking in the Coltranes is more or less like breaking in all speakers - a hundred hours or so to relax, and 6 months or so to get to the steady-state.

They do bass very well: they go very deep and are well-damped in a natural manner. Similar to the big Wilsons w/o the low/mid bass hump. Similar to the Vandy 5 (given the right amplification) but more tuneful and with higher resolution (if I remember correctly).

We haven't ever heard them evidence compression or distortion. We do not play them all that loud here - they are currently in a very live room, but at our usual digs they have been played quite loud). Note that these speaker's sound is very tightly controlled, not a big and open or relaxed sound (though we haven't yet tried big tube amps like your VTLs!). However, this does not mean they are over-damped - in fact it is this perfect balance that so beguiling. They reproduce notes in a very realistic manner - w/o any hint of compression or reluctance (though they do benefit from and were designed to be close to the front wall - not for bass augmentation but to add a bit of glow(?) to the midrange and to widen the soundstage).

Can't tell you how many times I have run from system to system after playing a CD on the Coltranes - seeing if the other systems do as well using *their* approach to sound reproduction (usually they do, but in their own way). This is not to be hyperbolic but to emphasize that we have 3 very different SOTA speaker systems here (horns, stats, cones) - all very good at what they do - and the interesting thing is that they all do it differently.

The U1s. We are remodeling and we left the Soundlabs and the Edge Refs at the house - safely wrapped up - with the plan being to finish the demo room #2 in about 6 weeks. It has now been 5 months and counting. Tick tick tick... But yes, once everything is finished there we will have the U1s, wired internally with Valhalla cable, hooked up to the Refs (and using Walker High definition links - which is about the extent of our tweakage on these speakers to date). When we get back we are also planning on putting the Walker in a central location so that all 3 systems can use it as a source using some not-quite-but-almost ridiculously long interconnect. Otherwise we will go crazy(ier) trying to pick which system gets the 'table....

Glad we could tempt you :-)

Anybody heard anything from Venture Audio?
Interesting thread and very informational. I hope Albert can keep us up to date on his findings.

The Martin Designs have caught my attention for a while now and very much wish to read more about it. Of course, being an amateur saxophone player, the name Coltrane certainly gets my attention. I have the Kharma 3.2s and I feel that ceramic drivers are a great compromise between the most detailed metallic based drivers and the warmest paper derived drivers. I do subscribe to the idea that there is a sonic signature that can be heard no matter how hard it is to detect. A metal mouthpiece will always sound different than a rubber mouthpiece.

With that in mind, I would venture to think that since the Coltrane uses ceramic drivers as their bass drivers, they would have better uniformity of voicing and tonal texture than the Kharmas that uses Nomex-Kevlar. But ceramic drivers, for all it's advantages as a midrange driver would inherently have disadvantages as a bass driver. For one thing, speaking from instrumental terms, you want your bass notes to have warmth. In order to achieve this warmth it is often important to dampen the higher harmonics so more of the lower harmonics can be heard. With that in mind, I would suspect the Kharma bass driver to be better at reproducing this desired bass quality. In the midrange and up, you want enough detail to allow enough of the lower harmonics through to round out the sound but in the bass, in a way, you want less detail since upper harmonics would actually obscure detail.

Mike. It's easy to say that one is more real, neutral and detailed. But how did this impression come about? On what basis do you base this by? If one without the knowledge of saxophone, is to hear Stan Getz and Coltrane back to back, I would venture to think that Getz would seem more "real" due to the warmth of Getz' sound, even though it's a matter of having a different voice. With that said, I can't agree more about other speaker systems doing things differently.
I forgot to add all this is just my thinking derived from my general observations from listening to drivers of different materials. I just get the feeling that ceramic bass drivers will reproduce some bass instruments better while the Nomex-Kevlar will produce other bass instruments better. I see the ceramic driver as quicker and probably with better articulation while the Nomex will provide more oomph in the process. I mean some people aren't exactly happy with the Kharma's bass performance so I can see how some people would prefer it in this case. I would love it if someone can help shed light as to the correctness of my theories :D