A synthesizer which has the ability to record and digitize short lengths (samples) of arbitrary sounds, and uses these as its waveform source (as opposed to using oscillators or other waveform-generating circults). A sampler has the ability to pitch-shift a recorded sound to correspond to the key played on the keyboard, allowing non-musical sounds such as spoken words, automobile engines, pots and pans, etc., to be played.(The first sample ever recorded on the first sampler was a barking dog.) The Fairlight CMI is known today as the first sampler, but it wasn’t really designed to be a sampler as such; the first synth designed specifically as a sampler was the E-mu Emulator.
The first samplers had little capability beyond simply recording and playing back sounds. However, modern samplers are usually equipped with most of the same sound-shaping components as other synthesizers -- VCFs, VCAs, and so on. Further, an essential component to modern sampling technique is the ability to loop part or all of a sample, in order to create an indefinitely sustainable tone, or a repeating phrase. Advanced samplers can play loops forwards and backwards, use different parts of the sample for attack, sustain, or release loops, or apply different processing to different parts of the loops. Other advanced capabilities include the ability to cut, paste, and merge blocks of samples; apply time, frequency, and formant shifting to samples, and draw or edit waveforms graphically.