Larry,
I agree with you all the way you know and I am just as wary of being sold snake oil like any other sensible person, which I hope that I am. In fact I am the first to doubt my own hearing, because in younger years I was with a group of colleagues who did research on the validity of testimony,of what people saw, experienced or rather think they experienced. The result of this research I have never forgotten and it taught me to be very careful and question and question again what my senses tell me. Not always, that would be stupid. (If I see a beautiful woman, I see a beautiful women, well knowing that beauty lies in the eyes of the beholder) But in this question which we are discussing, it would be advisable to question and to question unrelentingly. Like you, I would prefer a rational explanation of what is happening and what I am perceiving. But with the Bybees I have to give up. I was taught physics once, but Quantum physics are beyond me and I cannot form an opinion. If what my ears tell me, and with little "experiments" in front of my rig, friends etc will in their own words tell me more or less the same, I will have to be grudgingly content.
However, like you, I would also like to have a reasonable explanation of what in fact is going on, when you submit the Bybees into your system. I find it interesting to note, that in general, the description of what is happening points into the same direction:
Namely that there is a difference and that instruments sound more "natural", more like real music. So speaking in scientific terms, there is some empirical evidence which can be seen as pointing into the same direction. There is no theory however why this is so. All attempts to explain do not really satisfy. Bybee himself says, that he has no explanation for what is going on on the subatomic level, where he says his modules function. Here the circle seems to close for some : No explanation for what is happening is indeed close to snake oil. Because if snake oil works, it is only in the mind of the believer. No dirty tricks even needed here, auto-suggestion will do the work for you. We all know, how strong such an effect can be. Also in the case of Bybees: They are very, very expensive, so they must be good and if they are good, I must of course hear a difference for the better. Therefore, if someone would accuse me of having fallen into that trap, all argumentative powers I would summon for my defense would not suffice to convince my adversary, because even if he would hear the same thing as I, he could still argue that he has obviously fallen prey to the same illusion. Collective auto suggestion is a well known phenomenon. You cannot discount even that possibility.
So what to do? To my mind we have to admit, that if the Bybees work, and there is some evidence which could point into that direction, we cannot explain why. We have the choice of thinking that it is all fraud, because we can't explain it, or on the other hand, accept that the world is full of phenomena which exist but we (still?) don't know and cannot explain satisfactorily how they function. Our own body, at least quite a large part of its intricate interplay, especially on the "electro"-chemical level belongs to this category. There are quite of lot of people, who think that all that cannot be rationally explained must somehow be sham. Hence they tend to look down on the "believers". What they fail to see, is that they are also believers. Believers in what is basically a theoretical concept of reality, which works very well in practice but just simply is not the whole reality. That's why, John, I reacted a bit touchy when I read your first post. As you can see now, so I hope, I respect your position, actually share it, when it gets down to the nitty gritty. I will insist however that there is also dignity in an attitude, which, seemingly naive, is open to be surprised and taken in by phenomena, which cannot be explained. Call it a childlike openess for miracles, which remain only miracles of course, as long as we cannot explain them. Critical rationality in the explanation of world phenomena demands respect of course. Last not least due to the efforts of generations before us laying the foundations of Natural Science, without which modern life would not function. The other attitude, which I am defending now, demands respect as well, because of its courage to be able to be open and to believe and to have the strength to bear and live with the gap between belief and knowledge. Last not least of course also for having the guts to take it, being proven a fool and mistaken. Those two attitudes are often taken as absolute opposites, you are either for the one or for the other side. In fact, I feel, they should not oppose but complement each other. Each on its own is obviously not enough. The discussion about those Bybees to me show this up very nicely.
(Sorry to be so longwinded, in case you managed to read until here (: )
Cheers