Yo' Visionmike... it's ALL about the set up!!!
What I've found is that the closer to your mouth you get on the horn, the more it affects your sound... First your embochure and breath support, then your choice of mouthpice/reed/ligature... THEN the horn.
Now, this is assuming you have a properly working horn w/ no leaks or malfunctions etc.
On the horn tho' they say what it's made out of (brass, nickel, etc.) and if it's laqured or plated can also affect the sound slightly