In computer technology, a wavetable is a table of stored sound waves that are digitized samples of actual recorded sound. A wavetable is stored in read-only memory ( ROM ) on a sound card chip but it can also be supplemented with software. Originally, computer sounds (digital versions of analog waveforms) were generated through frequency modulation ( FM ). Prestoring sound waveforms in a lookup table improved quality and throughput.
Today's more advanced sound cards include wavetables with 32 "voices" or instruments (that are combined during creation and playback). Some sound cards work with software that provides additional voices. Wavetables are used as part of music or sound synthesizers that use the musical instrument digital interface ( MIDI ). MIDI lets you capture sound and play it back based on the commands in files that are essentially little "scripts" to the "orchestra" (one might think of it as a written description of what the conductor is doing and which instruments are being pointed to with the baton). A wavetable sound can be enhanced or modified using reverberation or other effects before it is saved in the table. Some wavetable chips include a special section for drum sounds to support rhythmic effects.
Many sound cards take advantage of Direct Memory Access ( DMA ). Many also include an FM synthesizer in order to play back sounds from older applications or files. A full-duplex sound card lets you record and playback at the same time or, if you're using Internet telephony, talk and hear at the same time.
Wavetable sound cards use digital signal processor ( DSP ) chips.