Two advanced editing techniques open up huge creative possibilities: manipulating time, and bouncing in place - committing sounds to audio so you can transform them further.
Tempo manipulation
Time-stretching
DAWs can change the length of audio without changing its pitch - warping in Ableton, Flex Time in Logic, elastic audio in Pro Tools. Each offers several algorithms, tuned for drums, tonal material or complex mixes.
Stretch further than intended and you get artefacts: graininess, phasiness, smeared transients. These can become effects in their own right - extreme stretching turns a short sound into an evolving texture.
Half-time and double-time
- Half-time - stretch a loop to twice its length, or program parts at half the rhythmic density, for a heavy, slow feel at the same tempo.
- Double-time - the reverse, for urgency.
- Switching between them across sections is a powerful arrangement tool.
Varispeed and repitching
Changing speed and pitch together - like speeding up or slowing down tape - keeps transients natural and changes character dramatically. Sped-up vocals and pitched-down drums are classic results.
Tempo automation
Gradual tempo changes - a slowdown into a breakdown, a speed-up into a drop - create tension and drama. Make sure warped audio follows the tempo map.
Bounce in place
Bounce in place (also called freeze and flatten, resample, or render in place) converts a track - an instrument with its effects - into an audio file on a new track.
Why bounce
- Commit decisions - stop endlessly tweaking a sound and move on.
- Save CPU - heavy synths and effect chains become a simple audio file.
- Transform further - once it is audio, you can chop, reverse, stretch, slice and resample it.
- Collaborate - audio opens in any DAW without your plug-ins.
Bounce as sound design
- Reverse a bounced pad or reverb tail for swells.
- Chop a bounced synth riff into new rhythms.
- Stretch a bounced sound into a texture.
- Resample repeatedly - process, bounce, process again. A sound that has been resampled several times through different chains can become unrecognisable from its source.
- Slice to a sampler and play the slices as a new instrument.
Good habits
- Keep the original track (muted or hidden) in case you need to go back.
- Name bounces clearly.
- Bounce with and without effects when you might need both.
Do this now
- Stretch a one-bar loop to eight bars with two different algorithms and compare the artefacts.
- Switch a beat to half-time for eight bars and back again.
- Bounce a synth part in place, reverse it, chop it into a new rhythm, and bounce the result again.