It depends on the brass instrument.
Piston and rotary valved instruments, such as trumpets, french horns, euphoniums, tubas, sousaphones, and the sort all have valves which direct the air through a longer or shorter section of tubes. The longer the tubing, the lower the note. The tension of the player's embouchure (how one's lips are set on the mouthpiece) and amount of air being blown also is a determining factor in the pitch. The tighter the embouchure, the higher the note is.
Slide operated instruments, such as trombones and baroque trumpets are essentially the same, only rather than having valves the player lengthens or shortens the amount of tubing on a slide.
Violin.
None of these intruments are part of the brass section. The Banjo though is most like a guitar.
we got brass intruments and timpani an a harpsichord and strings. and a conductor.
The trombone - it has a slide instead of valves, to change the pitch of the note.
The Bass Clarinet, Trumbone, Tuba, Cello, Bassoon, and others have a low pitch. Just to list a few.
For reed intruments it is the pressure and amount of air flow against it vibrates thus creating sound. In brass instruments the buzzing of lips and air flow to control the pitch of a note then moving valves or slide to play different notes
A pitch pipe.
BrassOn a brass instrument the bigger the mouthpiece the lower the pitch is.Must brass instrument have keys? The first brass band started around 1815.. All brass instruments have a mouthpiece you have to vibrate your lips.I play the baritone it is like the tuba or the trombone the baritone is smaller than the tuba and it has a no slide like the trombone. Brass instruments normally have a bell so the sound is loud. Most brass instruments are a gold colour or it is a silver colour. The brass instruments are made out of brass that is why it is called brass. The longer the tube is the lower the pitch is the shorter the tubing the high the pitch is. Brass can be classic or jazz.
The same way for any brass instrument--lower (pull out) the tuning slides
Tuba
tuba
The Tuba