A combination of two or more existing tracks layered together — typically a vocal from one over the instrumental of another.
Definition
A mashup is a combination of two or more existing tracks performed live by a DJ or pre-produced as a studio bootleg. The most common form layers the vocals of one track over the instrumental of another, creating an unexpected and often emotionally striking new combination. In trance, mashups are a celebrated DJ technique: a famous example is Above & Beyond's frequent live mashups of their own vocal stems over different instrumentals. Mashups are typically created in real time with cue points and loop tools (Rekordbox, Pioneer DJ effects), or pre-built as edits the DJ carries on USB. They overlap with bootlegs (which are also unauthorised) but specifically describe the layering of multiple tracks, where a bootleg may simply be an unauthorised remix of a single track.