mix stereo down to mono changes playback speed

i have a stereo track that i would like to be mono. when i select the track and use tracks > mix > mix stereo down to mono, it does indeed change the track to mono but it also changes the playback speed to much much faster. i checked the playback speed settings and they were still at the default 1.

i browsed around the web and this forum for answers and couldn’t find anything. any help is appreciated. thanks.

…That doesn’t happen to me.

Try [u]Split Stereo Track[/u]. That will give you two mono tracks and when you export they will be mixed to one mono track.

good work around for avoiding stereo, thanks. i’d love to figure out why it’s happening though. if anyone has a similar issue or thoughts on it let me know.

Perhaps you are changing the track sample rate somehow?

I’ve just run into the same problem. Here’s the setup currently, everything works and plays back fine.


Now after mixing several of the tracks down to mono:


You can see some of them have now changed in length and play back at the wrong speed.

Audacity 2.4.2 for reference.

There’s a bug in Audacity 2.4.2. If a stereo track has a different sample rate to the Project Rate, then “Mix Stereo to Mono” will incorrectly resample the audio. To work around the bug, Resample the track to the Project Rate before mixing to mono.

Windows 10 - This happens all the time. All files and project are 44100Hz. Mix down makes the track longer, slower, and lower in pitch. Separating into 2 mono tracks and deleting one is not a good answer. Wouldn’t these be a left track and a right track?? Not necessarily the same??

Are you looking in the right place for “Project Rate” (See: Selection Toolbar - Audacity Manual)
and track rate (See: Audio Tracks - Audacity Manual)

If you are, then you will need to give very detailed instructions for how to reproduce the problem.

This isn’t unique to Windows. I see the same behavior with Audacity 2.4.2 on OSX.

To duplicate the problem:

  1. create a project with a sample rate of 44,100
  2. import a stereo track with a sample rate of 48,000
  3. Mix the stereo track to mono

Expected is either of:

  1. new mono track has original sample rate of 48,000
  2. new mono track is resampled to project sample rate of 44,100

What actually happens is that the new mono track has been resampled to 44,100 but is still labeled and plays back as 48,000.

Once you know about the issue, you can work around with either

  1. resample before mixing
  2. correct the sample rate to 44,100 after mixing

Somebody above mentioned that this is a bug, but I wasn’t clear on whether it’s being tracked anywhere, and if it isn’t, how to help by filing a bug.

Yes it was a bug. It was logged and has been fixed for the next Audacity release.