I've narrowed it down...

Yes the Atma-Sphere S-30 was used in the voicing of Audiokinesis designs, but IIRC so was NuForce. Duke happens to be a dealer for both brands so he certainly had access to each.

My reasons for recommending these speakers is really about the flexibility and the fact that you can audition many types of amps with little worry as to compatibility. I have run 2 watt 45 and 12 watt EM7 SET amps, 35 watt EL-84 push pull, 70 watt KT-88/EL34 push pull, and 300 watt solid state amps with my speakers and the sound has always been pleasing, if not somewhat different.

I'm sure there are other flexible speaker designs out there and if I were the Op these would be the types of speakers I would focus on. I for one am in the camp that the system should be built around the speakers.

Unsound, you used the phrase

numerous requests

Your request for links which I provided does not constitute the above and my response also satisfied your lone request.

So your statement above is clearly misleading.

With regards to Norman Crowhurst, he does imply that negative feedback is beneficial. I pointed to him because he supports my claim about odd orders being distorted in a small degree by the presence of negative feedback. IOW he does not make a value judgment- that is made elsewhere, for example by Nelson Pass.

However in Crowhurst's text if one is familiar with Chaos Theory http://en.wikipedia.org/wiki/Chaos_theory we see that Crowhurst shows the formula for feedback; compared with that of a classic chaotic system that the two are nearly identical. He also mapped the Strange Attractor that is characteristic of the resulting Chaotic system that an amplifier is when using feedback. These things are not coincidental; the presence of bifurcation (distortion) is predicted by Chaos Theory and Crowhurst, despite Crowhurst's writings preceding the formation of the branch of science we call Chaos Theory.

Now the fact that Chaos Theory predicts negative feedback to be a destabilizing factor in amplifier design is something that should not be ignored (BTW, many designers will mistakenly claim that negative feedback is a stabilizing factor). However no value judgment is made, simply the expression of what is.

It is other studies including the rather simple and repeatable test (to which I have already referred) that make the value judgment. That judgment is not entirely mine, BTW, but a fairly large consensus in the audio community which agrees that odd orders are unpleasant to the human ear (and is the reason that over 50 years after the introduction of transistors, tubes have failed to become a footnote in audio history). All I have done is outline what is.

Atmasphere, the requests I made were for articles you have referenced before that are other than the Crowhurst. Since my previous post was not specific please refrain from making misleading statements regarding me. You generously provided a lengthy Crowhurst link in the past. In that article, Crowhurst suggested that negative feedback could be usefull, but it was important not to abuse it.
Once again, I will remind you that according to Nelson Pass some people prefer the odd 3rd order.
Once again, we seem to be straying off topic.

It has gotten some what off topic yet very interesting and informative,good thread IMO.
Atmasphere do DHT tubes behave differently from IDHT(Pentode) type tubes and would their response to feedback be the same? is one type more linear than the other? could that explain why some SET amps with DHT tubes can perform well without the need for feedback. Suprisingly the Yamamoto DAC I use is SS yet the builder uses zero feedback(he claims even 1 db of feedback is noticeable in the circuit).
Regards,

Charles1dad, I think you'll find plenty more of this in the archives.