A feature of some samplers which allows the performer to assemble one or more patches and samples, possibly with layering and effects, and then play notes while the sampler simultaneously records new samples of the played notes. In this manner a very complex built-up sound can be reduced to a single sample. This frees up resources in the sampler (such as allowing a note to be played with a single voice instead of requiring multiple voices), and it allows the new complex sound to be combined with other sounds, possibly for further resampling.