Mutes are devices fitted to musical instruments to alter the sound or timbre. Common trumpet mutes are the straight mute, cup mute, Harmon mute, wah-wah mute, bucket mute and plunger mute. Each creates its own unique and distinctive timbre of sound. The type of material has a great deal to do with the mute’s sound quality and price. Layered paper mutes are much less expensive than metal mutes. Some metal mutes incorporate copper to mellow the muted sound.