   a brass instrument is a musical instrument that produces sound by sympathetic vibration of air in a tubular resonator in sympathy with the vibration of the player's lips. brass instruments are also called labrosones, literally meaning "lip-vibrated instruments". there are several factors involved in producing different pitches on a brass instrument. slides, valves, crooks, or keys are used to change vibratory length of tubing, thus changing the available harmonic series, while the player's embouchure, lip tension and air flow serve to select the specific harmonic produced from the available series. the view of most scholars (see organology) is that the term "brass instrument" should be defined by the way the sound is made, as above, and not by whether the instrument is actually made of brass. thus one finds brass instruments made of wood, like the alphorn, the cornett, the serpent and the didgeridoo, while some woodwind instruments are made of brass, like the saxophone. == families == modern brass instruments generally come in one of two families: * valved brass instruments use a set of valves (typically three or four but as many as seven or more in some cases) operated by the player's fingers that introduce additional tubing, or crooks, into the instrument, changing its overall length. this family includes all of the modern brass instruments except the trombone: the trumpet, horn (also called french horn), euphonium, and tuba, as well as the cornet, flÃ¼gelhorn, tenor horn (alto horn), baritone horn, sousaphone, mellophone, and the saxhorn. as valved instruments are predominant among the brasses today, a more thorough discussion of their workings can be found below. the valves are usually piston valves, but can be rotary valves; the latter are the norm for the horn and are also prevalent on the tuba. * slide brass instruments use a slide to change the length of tubing. the main instruments in this category are the trombone family, though valve trombones are occasionally used, especially in jazz. the trombone family's ancestor, the sackbut, and the folk instrument bazooka are also in the slide family. there are two other families that have, in general, become functionally obsolete for 
Brass_instruments