Mute Music

A mute is a device used with a musical instrument to alter its timbre and, in some cases, reduce its volume. Mutes are most commonly associated with brass instruments and string instruments, particularly the trumpet, trombone, violin, and viola, though they are also used on guitars, pianos, and certain percussion instruments. While muting can serve practical purposes such as enabling quiet practice, its primary function is artistic, allowing performers and composers to achieve distinctive tone colours and expressive effects.
The act of using a mute is known as muting, and written instructions for its use are a standard feature of musical notation across several genres.

Definition and Function

According to The New Grove Dictionary of Music and Musicians, a mute is a device that modifies an instrument’s sound by reducing the intensity of certain partials while emphasising others, thereby reshaping the tonal spectrum. More generally, the term refers to any mechanism that muffles or softens sound. In brass instruments, mutes are sometimes called dampers, although damping more precisely refers to stopping vibrations after a sound has been produced.
A common misconception is that the sole purpose of a mute is to reduce loudness. In practice, most orchestral and jazz mutes primarily change tone colour rather than significantly decreasing volume. Only practice mutes are designed specifically for substantial sound reduction.

Notation and Performance Practice

Musical notation indicating the use of a mute typically appears as text above the staff. In classical music, the Italian instruction con sordino (or con sordini) directs performers to apply a mute, while senza sordino indicates its removal. Equivalent terms exist in other languages, such as avec sourdine and sans sourdine in French, and mit Dämpfer and ohne Dämpfer in German. For brass instruments, the word open often signals a return to unmuted playing.
Composers must allow sufficient time for performers to attach or remove mutes, although some designs permit rapid engagement. For hand muting, symbols such as o (open) and + (closed) may be used. In percussion and harp music, damping is sometimes indicated by a specific symbol resembling a coda or by diamond-shaped noteheads.

Brass Instrument Mutes

Mutes are especially prominent in brass playing, where they are usually inserted into the instrument’s bell or held against it. Trumpet and trombone players use the widest range of mutes, which may be made from metal, plastic, fibre, cardboard, or combinations of materials. In general, brass mutes attenuate lower frequencies while emphasising higher ones due to resonances created within the mute.
The use of trumpet mutes can be traced back to at least the early sixteenth century, and possibly earlier. While some early stoppers found in ancient tombs were likely protective rather than musical, written references to muted trumpets appear in Renaissance Europe. By the Baroque period, wooden mutes were in use, often raising pitch and requiring compensatory tubing.

Straight Mute

The straight mute is the most common brass mute and is widely used in both classical and jazz music. It is typically shaped as a truncated cone closed at the outward end, with cork pads allowing sound to escape around the bell. Acoustically, it acts as a high-pass filter, producing a bright, penetrating tone.
Straight mutes made of metal, usually aluminium, tend to sound more brilliant and forceful than those made from plastic or fibre. It is one of the few mutes that can be played effectively at loud dynamic levels. When a score specifies con sordino without further detail, it is generally assumed that a straight mute is intended. For the tuba, it is effectively the only standard mute in regular use.

Cup Mute

The cup mute resembles a straight mute with an additional inverted cup facing the bell. It produces a darker, more subdued sound and is used mainly in jazz contexts for trumpet and trombone. Some cup mutes allow adjustment of the cup’s distance from the bell, altering volume and tonal colour. Variants include the mica mute, designed for close microphone use, and the buzz-wah mute, which adds a buzzing resonance.

Harmon Mute

The Harmon mute, also known as the wah-wah or wow-wow mute, is a metal mute that completely seals the bell, forcing air through an internal chamber and out through a central hole. It may be used with or without a removable stem, producing markedly different sounds. Stem-out playing yields a distant, hollow tone, while stem-in playing creates a sharp, piercing effect. By moving the hand in front of the bell, performers can produce the characteristic “wah” sound associated with jazz trumpet solos.

String Instrument Mutes

On string instruments of the violin family, mutes are typically small devices clipped onto the bridge, reducing its vibration. This results in a softer, veiled tone rather than a dramatic volume reduction. String mutes have been used in classical music since at least the seventeenth century, often to convey intimacy, distance, or mystery.
For guitars, muting is commonly achieved by hand. Palm muting involves resting the side of the picking hand lightly on the strings near the bridge, producing a damped, percussive sound widely used in popular and rock music. Some guitars also feature mechanical mutes that replicate this effect.

Keyboard and Other Instruments

On the piano, muting is achieved through pedals rather than detachable devices. The soft pedal reduces volume and alters tone, while some instruments include a practice pedal that inserts a felt strip between hammers and strings for quiet playing. Percussion instruments may be muted by hand or with cloths, while harpists dampen strings using their hands to control resonance.