I have been playing alto for about two years and have a good sound. I have been playing a Martin Handcraft and the upper octave has a beautiful rounded singing tone - no problem with embouchure I think. I recently bought a Trevor James Signature Custom because I wanted a modern horn with fast keywork, and I had heard that these horns are a genuine pro level horn. I am finding that, as with the two TJ horns I have had in the past (The Horn Classic and the intermediate Signature Series - now Revolution II) when I hit the upper octave notes of G and A, I get a grating noise of the lower octave note coming through as well. This is only after a few minutes of playing, and does not happen all the time, as if it is an embouchure problem, but I wouldn't get this on the Martin - and if I go a note higher to B the problem disappears. Is it me, or a mouthpiece/reed issue? Maybe the Martin is just such a great horn that it didn't need me to put so much effort in, but a different horn needs more embouchure strength/control.