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.