Soundboard (music)

thumb|right|Soundboard of a [[harpsichord with Chladni patterns]]

thumb|right|A portion of the soundboard of a Vose & Sons upright piano

thumb|No. 15 indicates the Soundboard

A soundboard (or sounding board) is the surface of a string instrument that the strings vibrate against, usually via some sort of bridge. Depending on the instrument, it is also called a top, top plate, resonator, table, sound-table, or belly. It is usually made of a softwood, often spruce.

Pianos, guitars, banjos, and many other stringed instruments incorporate soundboards. The resonant properties of the soundboard and the interior of the instrument greatly increase the loudness of the vibrating strings. "The sound board is probably the most important element of a guitar in terms of its influence on the quality of the instrument's tone ."

The soundboard operates by the principle of forced vibration. The string gently vibrates the board, and despite their differences in size and composition, makes the board vibrate at exactly the same frequency. This produces the same sound as the string alone, differing only in timbre. The string would produce the same amount of energy without the board present, but the greater surface area of the soundboard moves a greater volume of air, which produces a louder sound. "Generally, stiffer boards will give a brighter edge to the sound than softer, more flexible boards....A good, dry soundboard has a certain 'live' tone while a poor one will have a relatively dead response," which the luthier may test during construction by thumping the board and listening for "brighter, more noticeable ring[ing]" so as to work the board "to the appropriate thinness".

References

ca:Caixa de ressonància