Tape / Vari-Speed Calculator
Tape / Vari-Speed Calculator
Change the tempo like tape and see exactly how far the pitch moves. Enter the original and new BPM to get the shift in semitones, cents and percent. Free.
Tape speed = pitch
| Speed change | Pitch shift |
|---|---|
| Double speed (2x) | +12 semitones (one octave up) |
| Half speed (0.5x) | -12 semitones (one octave down) |
| +50% faster | about +7 semitones |
| -10% slower | about -1.8 semitones |
Tape and vari-speed: change speed, change pitch
On tape, speed and pitch move together. Slow the machine down and the music drops in pitch and tempo at the same time; speed it up and it rises. This calculator shows exactly how far the pitch moves when you change the tempo, so you can recreate that classic vari-speed sound or match a sample to a new BPM.
The formula
The speed ratio is new BPM divided by original BPM. The pitch shift in semitones is twelve times the base-2 logarithm of that ratio. Halving the tempo drops the pitch a full octave; doubling it raises an octave.
FAQ
If I slow a track from 120 to 100 BPM on tape, how much does the pitch drop?
The ratio is 100/120 = 0.833, which is about -3.16 semitones (close to a minor third down).
Does changing tempo always change pitch?
On tape or simple vari-speed, yes. Modern DAW time-stretching can change tempo without pitch, but the tape sound comes from moving both together.
How do I get the tape slowdown effect?
Lower the playback speed, or pitch down and slow the tempo by the same ratio. This tool gives you the matching semitone amount.
Is this free?
Yes, free forever. The paid upgrade is the plugins on Meshplugins.com.
Want tape character on your tracks?
This shows the math. The plugins on Meshplugins.com bring the tape sound into your DAW. Pro studio results, bedroom-friendly.
Real sauce. No fluff.