Con sordino

A mute is a device fitted to a musical instrument to alter the sound produced: by affecting the timbre (or "tone"), reducing the volume, or most commonly both. The use of a mute is usually indicated in musical notation by the Italian direction con sordino and removed with the senza sordino direction, which means "without mute". On string instruments of the violin family, the mute takes the form of a device attached to the bridge of the instrument, dampening vibrations and resulting in a "softer", darker and more somber sound. On the cello and double bass, a wolf mute is often attached to the G-string (on the cello) and on the A-string (on the bass) between the bridge and the tailpiece to eliminate the wolf tone. On the guitar, a player may palm mute their guitar. Some instruments, such as the Fender Jaguar and the Rickenbacker 4001 and 4003 electric bass guitars have built-in string mutes.

A variety of mutes have been used on brass instruments, most of which either squeeze inside the bell of the instrument, or are hung or clipped to the outside of the bell. The most common type is the straight mute, a hollow, cone-shaped mute that fits into the bell of the instrument. The second most common brass mute is the cup mute. There are a range of other mutes for brass, such as the solotone mute, the buzz-wah mute, the Wah-wah mute, bucket mutes, and hats or plungers. Muting woodwind instruments is very uncommon. Saxophone mutes which are usually made of a soft material, which is placed in the bell to soften the tone. Percussion instruments often require no specialist mutes. The triangle is muted by simply gripping the instrument with the hand, stopping it from vibrating so much. Drums may require muting if they "ring" too much with cloth, gaffer tape or special rubber or foam rubber rings. The soft pedal of the piano can be seen as having the effect of a mute. It used to be common for pianos to be fitted with another kind of mute — a piece of felt or similar material which would sit between the hammers and the strings. This results in a very muffled and much quieter sound. It was not used in any serious context, but was useful for reducing the volume of the instrument when practicing and was often termed a "Practice Pedal". Few pianos, apart from some uprights, have this device today.

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Wikipedia