Trumpet Mufflers, also known as 'mutes, ' are devices that are used to reduce the sound of a trumpet. They are usually made of metal, plastic, or rubber and are placed inside the bell of the instrument. The mute alters the sound of the trumpet by dampening the vibrations of the air column within the instrument. This allows the musician to play with a softer, more mellow tone. Trumpet Mufflers are often used in jazz and classical music to create a unique sound.