String instrument: Encyclopedia II - String instrument - Sound amplification

String instrument - Sound amplification

String instrument - Through resonance

A vibrating string on its own makes only a very quiet sound, so string instruments are usually constructed in such a way that this sound is amplified either by a hollow resonating chamber, a soundboard, or both. On the violin, for example, the taut strings pass over a bridge resting on a hollow box. The strings' vibrations are distributed via the bridge to all surfaces of the instrument, and thus amplified.

Achieving effective and beautiful resonance is something of an art, and the makers of string instruments often seek very high quality woods to this end, particularly spruce (chosen for its combination of lightness and strength) and maple (a very hard wood).

In the early 20th century, the Stroh violin used a diaphragm-type resonator and a metal horn to amplify the string sound, much like early mechanical gramophones. Its use declined beginning about 1920, as electronic amplification came into use.

String instrument - Electric amplification

Electric string instruments use pick-ups to convert the string's vibrations into electrical waves which are amplified and then converted into sound by loudspeakers. Such instruments are often solid bodied, which makes them barely audible with the amplifier switched off. When the amplifier is switched on, they can be much louder than their acoustic counterparts. An advantage of this method is that it allows electronic manipulation of the sound; the guitar overdrive is a classic example.

Adapted from the Wikipedia article "Sound amplification", under the G.N U Free Docmentation License. Please also see http://en.wikipedia.org/wiki