i cant forward my debate with you gaer because i havent actually gone and learnt a brass instrument. i know you say you have dealt with perfect pitch players on brass instruments but sureley someone must have done it and im sure it can be done.
I'm not sure what you mean by "it can be done". I'm not sure what "it" is. However, if we took the time to ask fine instrumentalists how they keep track of pitch, how they hear, how they relate pitches, even then the answers might not be very satisfactory. Some of the people I've asked have merely shrugged their shoulders and said, "I just do it.".
But I do have a theory. It's only a theory, at best, and feel free to shoot it down. I think that how we hear relates the instruments we play, most of all to our primary instrument.
In all the theory classes I took, singers were weakest. Everyone joked about how the "could not hear", but this is totally unfair. Vocalists do not have something to link pitches to. To say that a singer who can't sightsing to save his or her life has a poor pitch sense does not necessarily make any sense. I would say that a singer who sings very well in tune has the most highly developed pitch sense of all of us, in a way, since he or she gets no help. Even on brass, which in the higher registers is almost totally controlled by the embouchure, you still land on one note or another. Trumpet, for instance, has high Bb, high C and high D all with open. Only under the rarest circumstances would you PLAY a high Bb with open, since it's going to be about 31 cents flat, but that's not the point. If you aim for a high C, you have a very good chance of hitting the wrong note, either a step low or a step high, if the lips are not set perfectly, even if you HEAR the note perfectly in your head. This problem is even worse on horn because the partials or overtones are closer together, and for all practical purposes you can hit just about any pitch with any fingering up very high, although many will be very out of tune. Ever wonder why horn players miss more notes than any other brass instrument? That's why.
Now, I've met SO many find brass players who nailed every note just as well as I could who told me, point blank, that they couldn't prehear a pitch to save their lives. I always wondered how they found the first pitch in any section, since the rest relate relatively, so I suspect some amount of absolute pitch sense is operating on a subconcious level.
I just think we don't know very much about how people hear. Even the term "perfect pitch" is incredibly misleading, since different people mean different things. How perfect is perfect? What is the minimum error plus or minus, in cents, that people can hear? Many problems have already been mentioned in this thread.
And sightsinging courses—how much do they help? Can they help everyone? What works best for most people? Syllables? Fixed do? Movable do? If your a pianist, what about just visualizing the keys themselves, bypassing any other system?
These are the kinds of things I'd like to hear discussed. I don't think we will discover many answers, but we sure as heck should be able to come up some very interesting questions, and asking questions is the first step towards deeper understanding.
Gary