A sampler is an electronic musical instrument similar in some respects to a synthesizer but instead of generating sounds, it uses recordings (or “samples”) of sounds that are loaded or recorded into it by the user. These sounds are then played back by means of the sampler program itself, a keyboard, sequencer or another triggering device to perform or compose music. Because these samples are now usually stored in digital memory, the information can be quickly accessed. A single sample may often be pitch-shifted to produce musical scales and chords.
Often samplers offer filters, modulation via low frequency oscillation and other synthesizer-like processes that allow the original sound to be modified in many different ways. Most samplers have polyphonic capabilities – they are able to play more than one note at the same time. Many are also multitimbral – they can play back different sounds simultaneously.