A sound box or sounding box (sometimes written soundbox) is an open chamber in the body of a

musical instrument A musical instrument is a device created or adapted to make musical sounds. In principle, any object that produces sound can be considered a musical instrument—it is through purpose that the object becomes a musical instrument. A person who pl ...

which modifies the sound of the instrument, and helps transfer that sound to the surrounding air. Objects respond more strongly to vibrations at certain frequencies, known as resonances. The frequency and strength of the resonances of the body of a musical instrument have a significant impact on the

tone quality In music, timbre ( ), also known as tone color or tone quality (from psychoacoustics), is the perceived sound quality of a musical note, sound or tone. Timbre distinguishes different types of sound production, such as choir voices and musical ...

it produces. The air inside the chamber has its own resonances, and these interact with the resonances of the body, altering the resonances of the instrument as a whole. The sound box typically adds resonances at lower frequencies, enhancing the lower- frequency response of the instrument. The distinctive sound of an instrument with a sound box owes a lot to the alteration made to the tone. A sound box is found in most

string instrument String instruments, stringed instruments, or chordophones are musical instruments that produce sound from vibrating strings when a performer plays or sounds the strings in some manner. Musicians play some string instruments by plucking the ...

s.Medieval and Tudor string instruments
/ref> The most notable exceptions are some electrically amplified instruments like the

solid body thumb , Sound sample of solid-body electric guitar. A solid-body musical instrument is a string instrument such as a guitar, bass or violin built without its normal sound box and relying on an electromagnetic pickup system to directly detect th ...

electric guitar or the electric violin, and the piano which uses only a sound board instead. Drumhead lutes such as the

banjo The banjo is a stringed instrument with a thin membrane stretched over a frame or cavity to form a resonator. The membrane is typically circular, and usually made of plastic, or occasionally animal skin. Early forms of the instrument were fashi ...

or '' erhu'' have at least one open end of the sound box covered with animal skin (or a skin-like acrylic material). Open back banjos are normally used for clawhammer and frailing, while those used for bluegrass have the back covered with a resonator. In some arrangements, loudspeakers are also mounted on a sound box to enhance their output, particularly bass speakers. One notable example of this arrangement is called the bass reflex enclosure. However, in these cases the box resonance is carefully tuned so as to make the sound more equal across frequencies, rather than to impart a particular character to the reinforced sound. *

Acoustic guitar An acoustic guitar is a musical instrument in the string family. When a string is plucked its vibration is transmitted from the bridge, resonating throughout the top of the guitar. It is also transmitted to the side and back of the instrument, ...

* Basic physics of the violin *

Filter (signal processing) In signal processing, a filter is a device or process that removes some unwanted components or features from a signal. Filtering is a class of signal processing, the defining feature of filters being the complete or partial suppression of some aspe ...

* Frequency response * Resonance chamber

References

String instrument construction {{string-instrument-stub