Mentioned first by Marin Mersenne in his 17th-century book Harmonie Universelle, the mute has long been a part of string playing. Nevertheless, many players regard muted sound as a single color, often giving more attention to whether a particular mute can be easily attached and removed. Artist-performers vary soft sounds through different combinations of bow speed, weight, and contact points as well as fingering. Similarly, building a collection of mutes, which can cost as little as $10 or less, can allow string players to choose from a wide palette of muted colors paralleling those used by many brass players.

When in playing position, the mute increases the mass of the bridge, thus reducing the amplitude of its vibrations and the strength of the produced harmonics, especially the higher harmonics. As a result, tone color generally becomes softer, less brilliant, and the amount of sound is reduced. However, the degree of these effects varies with the type of mute and materials from which it is made.

Mutes come in an array of sizes, shapes, and materials, each affecting the bridge somewhat differently—hence the variations in sound. For example, a large practice mute, which covers the entire top and outside edges of the bridge, with prongs extending between the strings, dampens the sound almost completely. Heavier metal mutes deaden more sound than rubber versions of similar design. Conversely, smaller mutes of less-dense material dampen the volume less. A mute with two prongs will hamper bridge vibrations differently from one with three. And leather, wood, and rubber mutes will each vibrate differently. Some mutes are mounted on the strings between bridge and tailpiece, always ready to be slipped into place, while others are removed from the instrument completely when not in use.

One of my favorite mutes is a unique two-pronged soft aluminum mute. Given to me by a former teacher many years ago, even then it was no longer commercially distributed. Its aluminum is so pliable that its feet can be easily adjusted to fit individual bridge thicknesses. This is an important consideration, because any mute must fit sufficiently tightly so as not to vibrate loose while playing, but not so tightly that the sound is too restricted or the bridge is marred.

This mute’s smooth, sensitive sound is—at the same time—covered but full and light, projecting with a strong, glowing character. Wonderful in both solo and chamber settings (as long as no quick changes between unmuted and muted sections are needed), it’s particularly effective in color-oriented writing such as Prokofiev’s Sonata in F Minor, Op. 80, and de Falla’s Suite Populaire.

One of my former students was so taken with the sound of this mute that he, along with a craftsman, handmade some slightly different models of two-pronged mutes from a slightly harder aluminum as well as other metals. While each had a slightly different sound, the one aluminum mute he gave me has a fine, focused sound that is a little firmer and somewhat brighter sounding than my soft aluminum mute. Unfortunately, the harder mute’s less-adjustable feet do not fit the bridge of my current instruments particularly well, so I seldom use it.

Leather, Ebony, Rosewood
Another of my favorites is a very soft, yellow, three-pronged leather mute. It is easily placed onto the bridge in varying degrees--placing it more deeply increases the muting effect, while a more shallow placement increases the sound projection. But unlike many other mutes, putting it lightly onto the bridge will not result in its eventually vibrating off while being played. Giving a more diffused, less focused sound, this mute is excellent for many impressionist works; I especially enjoy using it in much of the violin-piano writing by Karol Szymanowski (such as Fountains of Arethusa) and other composers influenced by him.