The Blue Devils have a DVD called Dynasty of Brass.
It is the single most fantastic thing you could own that will help you develop your brass sound, because you can turn it up loud on your home theater and play right along the Blue Devils with their 16 warm-up exercises you hear all the time when they play "in the lot." You can change the audio and have Wayne Downy talk to you over the playing about how to develop a "characteristic sound", or you can play the "trumpets only" audio, or the tubas, mellos, or baris. You get the idea.
Plus you can print out the music for the exercises on your laser printer, which includes Space Music, and Bb Tuning (what the old guys call F Tuning, but for Bb instruments).
Characteristic sound? Twenty or so DCI high brass trophies tell me Blue Devils have got it, in spades!