Call me ignorant or naieve, but I don't really know much about "responce" either. To me, the moutpiece could be a large factor on how your horn plays. But what do I know?
With me, I just play the darn thing.

If it sounds good to me and I am happy, then all is fine, and if it sounds bad, then I try to fix it.
Also, in trumpets that are soooo alike, like the Yamahas, would they not respond mostly the same to many people?
Cheers all.
Happy New Years
__________________
Eric Sproul
Practice is like filling a leaky bucket
Bb: Yamaha Xeno 8335
C: Bach Stadivarious 239L and 25A leadpipe (Owned by Eric Sholtz)
Flugel: Yamaha Bobby Shew 6310Z
Mouthpieces: GR tech
www.stadband.ca