What do trombone players to change there pitches?

Trombone players change pitches by moving a slide in and out of the instrument. The longer the slide is, the lower the pitch will be. Pulling the slide out to increase its length results in a lower pitched note. Conversely, pushing the slide in towards the player’s body shortens the tubes length, thereby raising the pitch.

Trombonists are also able to change pitches using their embouchure, or the way they shape their lips and mouth around the mouthpiece. By controlling the tension and shape of their embouchure, trombonists can produce different notes and tones without having to move the slide.