Realtime tempo modification

Currently (Audacity 2.3.0), it is possible to modify the playback speed in realtime, but it comes with a change in pitch.

It is also possible to modify the tempo without changing the pitch by using Effects > Change Tempo…, but this is not a realtime effect.

When doing ear training or music transcription, it is very useful to have access to realtime tempo change in order to tackle a particular part of a tune for instance. One can use Effects > Change Tempo…, but it has to be applied to get the desired effect, and (once the difficulty has been analyzed for instance) undone to get back to the original tempo.

There is currently a slider to modify the playback speed in realtime. An option could be a checkbox to select to alter the tempo instead of the speed:

I checked the Feature Request WIki page before creating this topic, apologize if I missed something in it!

Actually it is already listed, but not easy to find unless you know that it is there.
It is currently listed as:

“Play at tempo (without changing pitch)”

I’ve added your “vote” for this feature.
This is a long-standing feature request, but has been difficult to implement due to technical difficulties in the audio playback code. Some of these difficulties have been resolved very recently, so we are at least moving in the right direction, albeit slowly :wink:

Thank you for your quick answer and your clarification! Indeed, I had missed this line. Thanks for adding my vote to it :slight_smile:

Hopefully the recent improvements you mention means we’ll have this feature sooner rather than later :wink:

I am not a very heavy user of Audacity (i.e. I’m not a sound engineer or anything like this), but this is really a wonderful swiss army knife for anything audio. I recently discovered there was a very thorough spectrogram mode which is very helpful to investigate what notes are being played during a Jazz solo for instance! So thanks to you and the Audacity contributors for creating and maintaining such a great tool!

I would love to say that it will be soon, but it is a very small team of developers, and there are a lot of competing areas for them to work on. All that I can say, is that we are constantly working to improve Audacity.

Please add my vote to this feature.

I have two 2-hour recordings from a self-contained Tascam lavalier mic during a shoot. I guess I should have started a stopwatch and written down when we filmed different takes of each shot. I have to review the whole thing to select the right bits for each take.

Since I can’t do that without the chipmunk effect, I have to listen to the entire thing.

Vote added.

If you have an idea of what was said when (so that you don’t need to listen to the entire thing), or a script, then you may be able to skip through the recording more quickly with either “Quick Play” ( or “Seeking” from the “scrub ruler” (

Please add another vote for this feature.

This would make Audacity a rival to programs like “The Amazing Slow Downer” or “Transcribe!”.

I just want to be able to slow the tempo down during play and not actually edit or change the audio. This would make it so much easier to learn to play a new song.

Thank you all for a great program. Audacity already rocks. This feature would make it rock even more.


Are you aware that you can increase the “preview” length for effects?
For example, you could increase the preview length from 6 seconds (default), to say 30 seconds. You would then be able to use the Preview button in the “Change Tempo” effect to listen to up to 30 seconds at a different tempo without modifying the audio.

Yes I am aware of this and it is handy, but it does not help when trying to learn to play a new section of music. Some time I just need to repeat a bar or 2 and other times I want to repeat the whole line or chorus at a slower tempo in order to be able to learn that section of music. Often I am going from one section to another of different length in time. It would be nice if the Play-At-Speed tool bar could be changed to Play-At-Tempo tool bar.