Brass instruments include the trumpet, trombone, French horn, tuba, and other instruments consisting of a horn driven by lip vibrations at one end. The mouthpiece of a brass instrument is generally cup-shaped, and the lips vibrate at a frequency near that of the sounding note.
There are three main components needed in synthesis models for brass instruments: the mouthpiece, bore, and bell. Both cylindrical and conical bores are accurately modeled using digital waveguide techniques, as discussed in previous chapters (see §C.18 for further discussion). However, bore models may need to simulate nonlinear shock wave formation at high dynamic levels [199,344], which is relatively expensive to do . The bell, which flares more rapidly than conical (typically exponentially10.21) does not support true traveling waves , and so it must be modeled using a more general simulation technique, such as by means of reflection and transmission filters (discussed in §9.7.2 below).