Pitch Shifting and Time Stretching: What Actually Works
Changing the pitch of audio without changing its length, or changing its length without changing its pitch.
Tomas Lindqvist
Where most projects go wrong
The usual mistakes:
- Large stretches on speech
- Chipmunk voices from unpreserved formants
- Stacking several stretch passes
- Using stretching to hide editing problems
What good looks like instead
- Keep changes small where possible
- Preserve formants when shifting voices
- Choose algorithms suited to speech or music
- Compare against the original
- Render changes before further processing
Why it matters
These tools fit music to picture and fix timing, but pushing them too far creates robotic or watery artifacts.
The specs that matter
| Measure | Figure |
|---|---|
| Time stretching | changes duration while keeping pitch |
| Pitch shifting | changes pitch while keeping duration |
| Formants | preserving formants keeps voices sounding natural |
| Tools | Audacity and Adobe Audition include pitch and tempo effects |
Knowing when to hand it over
Tip: Bring in help when music must fit picture without audible artifacts.
Where this comes from
- Audacity — Audacity Manual
- Adobe Help Center — Audition User Guide
The figures and practices above come from the sources listed.
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Where to go next
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