Paulstretch
From Audacity Manual
Use Paulstretch to slow down audio by extreme amounts without changing the pitch.
- Accessed by:
Stretch Factor
This sets how much longer the processed sound will be relative to the original. For example, setting this to 10 will stretch 1 minute of audio into approximately 10 minutes of audio, somewhat less at higher Time Resolutions.
Time Resolution (seconds)
In order for the effect to work, this value must be smaller than the selected area in the waveform.
Small values have good time resolution, but poor frequency resolution, so you may still be able to detect a rhythm (albeit a very slow rhythm). Large values have poor time resolution, but have great frequency resolution, so transients will disappear but pitch differences may be better preserved.
Usually, a value of 0.25 seconds is good for most music. Very large values (greater than 2 seconds) can be used for special effects such as "smearing" a song into a sound-texture, even if the Stretch Factor is close to 1.0.
