PreSonus Blog

Play Faster with Tape Stretch

How to Play Faster—By Playing Slower covered how to slow down tempo of non-MIDI based music without changing pitch. This allows playing a difficult part at a slower speed, and then speeding the part back up to the desired tempo. However, this method may produce artifacts, because time-stretching algorithms aren’t perfect (yet…).

With tape, musicians used variable-speed recorders to implement the same technique. However, because this approach locked pitch and tempo together, slowing down the tempo also lowered pitch. So, you’d need to learn the song in a different key, or retune your instrument to match the lower pitch. Speeding the tape back up to its original tempo sped up the slower overdub, and raised its pitch as well.

Studio One’s “Tape” stretch mode works the same way as variable-speed tape, and unlike other stretch methods, produces zero artifacts. You still need to learn the part in a different key, but sometimes this is a good thing. When you play along at the slower tempo and then speed the part back up again, the instrument’s timbre becomes brighter—which might be just what a song needs. Similarly, you can record at a faster speed, and then slow back down for a sound that’s more like downtuning. What’s more, with stringed instruments, it’s possible to record with a different voicing that might be more effective, or provide additional contrast if you’re layering parts.

How to Do It

1. Rather than try to slow down an entire Song, position the loop markers at the beginning and end. Choose Song > Export Mixdown to create a premix of the Song. Under Export Range, choose “Between Loop.” Under Options, check “Import to Track” (fig. 1).

Figure 1: Export the premix.

2. Mute all Song tracks except the imported premix.

3. Select the premix, and open its Inspector (F4).

4. For Timestretch mode, choose “Tape” (fig. 2).

Figure 2: Inspector settings for the premix.

5. Further down in the Inspector, locate the “Speedup” parameter.

6. Enter a Speedup value that “lands” on a key, as shown in fig. 3. For example, a Speedup setting of 0.89089 slows the tempo to 89% of its current value, and transposes pitch down 2 semitones. Enter all 6 digits for correct tuning, even though Speedup displays only 3 digits (Studio One knows the extra digits are there). Hit Return.

7. Create a new track, and record your overdub at the slower tempo, in the different key.

8. When you’re done, make sure your overdub extends to the song’s beginning. If there’s a gap, use the Paint tool to create a blank event that extends from the song’s beginning to the overdub. Select the blank clip and overdub, and then type Ctrl+B to turn them into a single event.

9. Click on the overdub event, and set Timestretch to Tape. transpose it up by as much as it was transposed down. For example, if the track was transposed down 2 semitones, enter a Speedup time of 1.12246 to transpose it back up two semitones. Hit return.

10. Done!

Figure 3: Speedup parameter values for different transpositions.