Why use percussive link tracks? Firstly, many songs do not have sufficient length of Intro and Outro to allow a gradual transition between tracks. Secondly, not all playout software is musical key aware, and beat-matched transitions between tunes in incompatible keys can easily sound awful, a musical train-wreck. The use of short percussive links with only atonal beats in the Intro and Outro sections overcomes these issues without time consuming preparative 'DJ edits' and categorisation by key.
In the illustrations below, BLUE shows parts of the waveforms not mixed with other tracks, and played at natural tempo and volume. The GOLD parts are subject to tempo then volume adjustment upon playout. Any RED parts are unplayed in the resulting mix. Bar, or measure, downbeats are indicated by MAGENTA marks, other beats by GREEN. Six markers (cue-points) are set at downbeats in each track, labelled here for reference a, b, c, d, e, or f.
a) Intro pre-match range start
b) Intro match point - typically at the start of a musical phrase
c) Intro post-match range end - typically at the start of the first verse of the track
d) Outro pre-match range start
e) Outro match point - typically at the start of the final or penultimate musical phrase
f) Outro post-match range end
General operation, starting with normal volume on outgoing track and zero volume on incoming:
a) At match-range start, adjust tempo of outgoing track to that of incoming track.
b) Once tempos are matched, fade out outgoing track and fade in the incoming (or crossfade).
