Sound box

The frequency and strength of the resonances of the body of a musical instrument have a significant impact on the tone quality it produces.

The sound box typically adds resonances at lower frequencies, enhancing the lower-frequency response of the instrument.

Drumhead lutes such as the banjo or erhu have at least one open end of the sound box covered with animal skin (or a skin-like acrylic material).

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.