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 ("with mute") and removed with the direction senza sordino ("without mute") or via sordino ("mute off"). The spelling sordino is standard in musical notation, but in Italian, the proper spelling is sordina (a feminine noun).

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.

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. Usually this takes the form of a small three-prong implement made of wood or a rubber device which is attached to the top of the bridge. With wooden mutes, one prong is slid between each pair of strings. A rubber mute slides onto the end of the bridge for use and then is slid off when it is not needed.

A famous use of string mutes is in the introduction of Prokofiev's Romeo and Juliet. All the strings are muted (con sordini) so the sound appears to grow out of the initial discord, as if appearing from nothing. The sound is softer and more lyrical and flowing. Anything which reduces the bridge vibrations will suffice as a DIY way to mute for amateur or beginning musicians, such as spring-loaded clothes pegs, for example, have been used. A more modern invention is a mute which sits on the strings between the bridge and tailpiece of the instrument. This is slid into place right next to the bridge to produce the same effect as the detachable three-pronged mutes.

Heavy practice mutes or "hotel mutes" are available for string instruments. Some are made out of heavy rubber. Some models for violin and viola are made of metal. These also fix onto the bridge of the instrument and greatly reduce its loudness, enabling string players to practice at night in a bedroom or hotel room, without disturbing others. Recently, practice mutes have been used in contemporary music for a special color, appearing in works by John Corigliano and Gérard Grisey.

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. This does not change the timbre of the instrument on the whole, but helps to eliminate the wolf tone which is found on many cellos around a sixth or seventh above the open G-string. When used to eliminate wolf tones on a double bass, it is often attached on the A-string.

The violin mute was first described by Marin Mersenne in 1636. One of the earliest examples in the use of muted string instruments is found in Act II of Jean-Baptiste Lully's Armide, when the entire string section sporadically plays with mutes. However, the use of mutes did not become widespread in classical music until the 19th century when romantic composers sought new timbres from the orchestra. By the 20th century, the use of mutes was common for bowed instruments.

On the guitar, a player may palm mute the guitar. To palm mute, the player uses the side of the hand, or the edge of the palm, closest to the bridge to cover the strings. This shortens the sustain significantly causing a muting effect. This is a very common technique by electric guitar and bass guitar players in heavy metal music and hard rock. In metal, when palm-muting is used with a heavily distorted guitar amplifier, it is used to create a characteristic "crunch" sound with power chords and low-register riffs.

The Fender Jaguar has a built-in (but removable) spring-loaded string dampening device installed near the bridge of the guitar that can be utilized to simulate the palm muting technique while allowing the picking hand to be more mobile. Various Gretches like the 6120, the 6070 and the Country Gentleman have also been equipped with similar dampeners near their bridges, but Gretsch's design prevents them from being removed like the device on the Jaguar. The popular Rickenbacker 4001 and 4003 model electric bass guitar, along with earlier model Music Man basses, also have adjustable string mutes integrated into their bridge/tailpiece assemblies, which can be used to give the instrument a more percussive sound or to simulate the shorter sustain of an upright bass. Other electric basses have mutes built into their bridge covers. Built-in mutes may be made from foam, which reduces the length that notes can vibrate.

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. These mutes are typically made out of aluminum, brass, or copper metal, but more economical plaster, cardboard, and plastic versions exist. Each material produces a distinctive sound. Mutes can take advantage of this by using materials like cane, leather, and steel.

Mutes will usually make the instrument play sharp. High quality mutes try to reduce intonation issues while maintaining the characteristic sound. Even so, it is often necessary for the musician to accommodate by adjusting the tuning slide, or their own embouchure.

The most common type is the straight mute, a hollow, cone-shaped mute that fits into the bell of the instrument. This results in a more metallic, sometimes nasal sound, and when played at loud volumes can result in a very piercing note. Straight mutes have small pieces of cork attached to the end that squeeze against the inside of the bell and hold the mute in place. Straight mutes are available for all brass instruments, including the tuba.

The second most common brass mute is the cup mute. Cup mutes are similar to straight mutes, but have a cup portion attached to the end of the mute's cone. This allows the sound to bounce back towards the instrument bell before making its way through the gap between the cup and bell, producing a more muffled darker tone. Traditionally, cup mutes are made from fiber materials and have a very distinctive sound. Cup mutes can be made from metal, plastic or fiber materials. Some metal cup mutes have an adjustable cup portion which can be moved towards or away from the brass instrument bell to further color the tone. Newer cup mutes now offer an adjustable cup portion although made from a fiber composite material, allowing the user to adjust the cup while preserving the traditional cup mute sound.

The solotone mute (labeled by Humes and Berg as the "cleartone" mute), also called a mega-mute, is shaped like a long straight mute, and includes sound baffles inside the mute that accentuate treble frequencies. It is rarely written for today but was common in jazz ensemble music written between 1930 and 1950. The most trademark use of the solo-tone mute was in Tommy Dorsey's trombone solo in "Song of India", recorded January 1, 1937.

The buzz-wah mute is shaped like a cup but is designed with vibrating membranes on the mute, as if several kazoos were attached to the instrument. This mute creates a very unusual and recognizable sound, but is quite difficult to play, and is extremely rare in performance. In the early 1920s, Joe "King" Oliver was known to hold a kazoo in the bell of his cornet to achieve the buzz effect. Commercial versions of this type of mute soon followed. The earliest version of this was the "Humes Jazzer" patented by Guy B. Humes in the mid-1920s.^[1]

The Wah-wah mute (also known by the brand name Harmon) is a hollow, bulbous mute in two parts. Unlike the more common straight or cup mutes, the Harmon mute has a solid ring of cork that completely blocks the air leaving the bell, forcing all of it into the mute. At the front of the mute, there is a cup on a tube (sometimes called the "stem") that can be slid in or out, or removed completely, depending on the composer's direction or the player's preference. This mute produces a tinny, shallow sound which can be varied by adjusting the mute and via manipulation with the fingers at the cup end. Harmon mutes are commonly used only on trumpets and trombones.

Miles Davis often played through a Harmon mute without the stem. This formed a characteristic sound, and greatly influenced the jazz community in such classic tracks as "All Blues".

Bucket mutes attach to the rim of the bell with springs and contain cotton, foam or a similar substance. The effect is removal of high frequencies and a soft, muffled tone. Some modern bucket mutes (by JoRal for example) are designed as oversized straight mutes filled with batting, with large holes in along the side. These are held in the bell of the instrument with strips of cork, like straight and cup mutes. Players often find a trade-off between spring-style mutes, which can prevent quick transitions and cone-shaped mutes that squeeze into the bell, which can cause back-pressure. Modernized flexible spring-style clips on bucket mutes make transitioning fast and also eliminate back-pressure.

Derby mutes or hat mutes (also known as Bowler Hats, and also confusingly and incorrectly called Wah-wah mutes) were common in jazz from the 1920s when King Oliver played and others wrote for them. These mutes were originally actual bowler hats. In the 1920s, with the advent of aluminum as an art metal, derby mutes were stamped out of metal by companies such as Meta-Lite, Elton, and later Harmon. These replaced the use of the actual bowler derbies. From the 1950s to the present derby mutes were made of fibre (a resin impregnated cardboard). They are still available from the Humes & Berg Company.

Derby mutes are typically mounted on stands in front of the trumpet and trombone players, to permit quick movement of the bell in and out of the hat quickly, although they can be opened and closed over the bell of the instrument by hand. These mutes have fallen somewhat out of favor in recent years, as bucket mutes or playing into the music stand can give a somewhat similar, although unvarying sound.

Stop or Stopping mutes are unique to the French horn. The term hand-stopping involves the hornist inserting his/her hand into the bell of the instrument. A buzzing sound results, and the tone is raised a semitone from the shortening of the effective length of the vibrating air column. At lower intervals, application of this technique is very demanding. At the pedal level, it is nearly impossible (as in the final movement of Tchaikovsky's Symphony No. 6). To remedy this, a small mute made of brass, with a small branch and tiny brass bell, is substituted for the hand. It still takes an enormous amount of air to achieve the "stopped" sound, but is certainly possible for an experienced player. Stopping, whether accomplished by hand or with a mute, raises the pitch to such an extent that horn players have traditionally transposed the muted notes, fingering a half-step lower than written, but a line of self-transposing stop mutes have recently been developed in Japan.

Plunger mutes are simply rubber sink or toilet plungers with the wooden handle removed (but can be purchased from certain mute companies). Some musicians cut holes in the rubber to alter the sound produced. Plungers are often used in a manner similar to the hat mute, where the musician manipulates the plunger in front of the bell while playing with their other hand. A "closed" plunger gives a tone similar to a tightly inserted cup mute, and a skilled plunger technician can often produce sounds similar to the human voice.

In Duke Ellington's orchestra, trombonist Tricky Sam Nanton was noted for his work with the "plumber's friend". The Glenn Miller band made a wooden red and white plunger popularly called the "Tuxedo Plunger" (used in the band's hit tune "Tuxedo Junction"). For a combination of straight mute sound with the readily manipulated plunger, Pixie mutes are used. More recently, some players use a plunger made from a dog toy called the "Jolly Ball Tug-n'-Toss" cut in half.

This mute is similar to a straight mute, but is generally used with a plunger mute to get a "dirtier" sound. It was a favorite of Sam Nanton of the Duke Ellington Orchestra.

Practice mutes, also known as Whispa, whisper, or hotel mutes, are similar to straight mutes in appearance, but have a solid ring of cork that prevents air from escaping from the bell like a Harmon mute. There are sound baffles inside the mute, and tiny holes in the sides of the mute that allow air to escape silently. These mutes are extremely quiet and are rarely used in performance. They are usually used for privacy and to avoid disturbing bystanders during practice sessions.

The trumpet playing community has embraced a method for making an inexpensive practice mute out of a conical plastic "Renuzit" brand gel air freshener container filled with tissue or fabric.^[2] The mute is held in the bell with weatherstripping. The self-assembly allows each player to custom-fit the mute to the bell of their trumpet, or alter the sound quality and muffling effect.

The RingMute is a dampening ring that attaches to the bell rim of a standard Bb trumpet. Since the mute is attached to the outside of the trumpet and is not placed inside the trumpet, it is known as an external mute. The construction consists of a lightweight urethane foam ring held in place by an adhesive strip. The purpose of the RingMute is twofold: 1)According to the University of New South Wales, Sydney Australia, the highest overtones that typically give the trumpet its brassy sound, are emitted at the bell rim.(Brass Acoustics: An Introduction(newt.phys.unsw.edu.au/jw/brassacoustics.html). The absorbent foam dampening ring is attached to the bell rim of a Bb trumpet and assists in diminishing the higher overtones. This is helpful when performing in small areas where the sound of a trumpet can be overbearing but the performer wishes to maintain an open trumpet sound. 2)The other use of the RingMute is when practicing in apartments or close areas where the sound can be disturbing to others. An interesting feature that the RingMute possesses that many mutes do not is that intonation is basically unaltered. With almost all internal mutes such as Harmon, Straight, Cup, Renuzit, etc. that are fitted into the trumpet, the main tuning slide must be extended from its normal setting in order to be in tune. This adjustment is due to the opening of the trumpet bell being plugged. The RingMute Dampening Ring (by virtue of being an external mute and fitted onto the trumpet)requires no altering of the main tuning slide.

Yamaha produces an electronic practice mute system known as Silent Brass, with models for tuba, euphonium, horn, trombone/bass trombone, alto trombone/flugelhorn, trumpet/cornet, and piccolo trumpet.^[3] It consists of a practice mute with a built-in microphone and 1/8th inch jack, which connects to a pocket amplifier with volume control and headphone output.^[4] It is sometimes used in combination with effects pedals or other devices to completely change the sound of the instrument.^[5][6]

Sound from woodwinds emanates mainly from the holes in the instrument's body. Muting woodwind instruments is very uncommon, and in the case of the flute is almost unknown. In the 18th century purpose-built mutes existed for the oboe and clarinet, but in the rare cases when one of these instruments is muted today a handkerchief is usually stuffed up the bell resulting in a muffled sound. Some bassoonists still use purpose-built mutes, generally as a way of regulating volume at extremes of the instrument's register.

There exist saxophone mutes which are usually made of a soft material (such as velvet, silk or chenille) woven around a hard inner ring (usually brass or plastic). This mute is placed in the bell, most commonly perpendicularly to the body of the saxophone. This softens the tones of the saxophone somewhat, and can be useful in classical settings as it also dampens the sound a bit. They are not in common use, but they are not rare either. They are usually only made for the alto saxophone, although bigger and smaller ones can be made and used for higher and lower registers of saxophone. Some companies currently produce mutes that cover the entirety of the instrument (such as the E-Sax Whisper mute and the Silent Sax case), thus dramatically diminishing the volume of sound produced. To date their overall effectiveness is still in question.

Percussion instruments often require no specialist mutes. The triangle, for example, is muted by simply gripping the instrument with the hand, stopping it from vibrating so much. Cymbalists, similarly, will grip the cymbals with their hand, or simply strike crash cymbals together to stop excessive vibration

Drums may require muting if they "ring" too much. They can be muted by laying a small piece of cloth (or in a pinch, a credit card, adhesive bandages, or even sanitary napkins and duct or gaffer tape for larger drums) over their skin resulting in a muffled sound, but there are also specialized adhesive cloth mutes that stick to the head of the drum. Timpani players will run their fingers across the surface of the drum-head to control unwanted resonance.

For the snare drum, tenor drums, or the entire drum (trap) set, drum and cymbal mute pads (such as SoundOff by Evans, Deadhead Pads by DW Drum Workshop, and Vic Firth Drum Set Mutes, and many others) are available for playing quietly while practicing. These usually consist of a piece of rubber or foam rubber that is laid on top of each drum head and cymbal. Computer mouse pads (whole or pieces) may also be placed on drum heads and cymbals to achieve a similar effect.

Many struck idiophones, such as the claves, can be muted by varying the way the instruments are held or struck in order to reduce their resonance. Shaken idiophones, such as maracas, can often be muted by holding or squeezing the ball section in the palm of the hand instead of holding them by the handle, which can alter the tone as well as the volume for added versatility during recording sessions.

Traditionally, a military band playing for a funeral would cover the drums with cloth, producing a muffled tone suitable to the solemn occasion.

The soft pedal of the piano can be seen as having the effect of a mute. In a grand piano, depressing the soft pedal shifts the action slightly to one side, making the hammers hit only two of the three strings for each note (or one of the two at lower registers). This results in a quieter and "thinner" sound. In some upright pianos, the soft pedal instead moves the hammers slightly closer to the strings, shortening the blow distance and weakening the strike. The effect is then markedly smaller than in the grand piano, and is a matter of volume but not timbre.

Indication that the soft pedal should be used is the instruction una corda or sometimes due corde, with tre corde or sometimes tutte le corde cancelling it. On early pianos it was possible by use of the soft pedal to play only one, two, or all three strings, making the distinction between una corda (one string) and due corde (two strings) meaningful; but this is no longer the case.

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.

To confuse matters, the instruction senza sordino (or some variant) is sometimes used to indicate continuous application of the sustain pedal on a piano, throughout a long section or an entire movement (as opposed to the standard use of [[INLINE_IMAGE|//upload.wikimedia.org/wikipedia/commons/thumb/0/08/Pedal_Mark_1.svg/30px-Pedal_Mark_1.svg.png|//upload.wikimedia.org/wikipedia/commons/thumb/0/08/Pedal_Mark_1.svg/45px-Pedal_Mark_1.svg.png 1.5x, //upload.wikimedia.org/wikipedia/commons/thumb/0/08/Pedal_Mark_1.svg/60px-Pedal_Mark_1.svg.png 2x|Pedal Mark 1.svg|h20|w30]], or alternatively a brace mark, written below the staff, for short applications of the pedal). The sordino of this notation refers to the felt dampers, each of which stops the sound of a note's strings when the note is not being played. When all the dampers are lifted by the sustain pedal (senza sordino), all the strings of the piano are allowed to sound, resulting in a complex sound when all strings are free to sound sympathetically with other strings. (See Moonlight Sonata for a classic example of senza sordino.)

A piano tuner will use another kind of mute with a piano; a rubber or felt wedge, which is inserted between strings to make sure only the desired string in a "unison" (that is, in the strings for one note) is sounding. A felt strip can also be inserted and "braided" between strings, to mute several strings at once.

Finally, a very simple and basic way to somewhat muffle the sound of a piano when practicing is to cover it with a blanket.