Stereo to Mono Conversions

Audacity 3 Help Forum macOS
1

Hello All,

I think I may have found a bug in audacity 2.4.X. I can’t say if it is a bug or just something I don’t understand. I do a lot of Stereo to Mono conversions. I have no problem with this when there is only one track or if all of the tracks are recorded at 44.1 kHz. The problem occurs when there are multi-tracks and one of them is 48.0 kHz. When I convert this track to mono the recording is sped up. However, take that same track open a new Audacity window and it converts just fine. Then I can copy and paste it back to my project. I first noticed this problem with 2.4.0 and it has continued on to 2.4.2. Is this expected or is it a bug?

Thank you!

-Ron

2

Please give step by step instructions to reproduce the issue.

3

To recreate this issue you will need to:

  1. Create a new project.
  2. Record some audio or import audio that is 44.1 kHz it can be a mono or stereo track. I mostly have mono tracks.
  3. Import a stereo track that was recorded at 48.0 kHz
  4. Select the 48.0 kHz track by clicking the select button.
  5. Play that track to make sure it sounds correct.
  6. Select Track>Mix>Mix Stereo Down To Mono
  7. Play converted track. For me, it is sped up every time.

Thanks,
-Ron

4

Terrific description. Yes that’s a bug. I’ll log it on the bug tracker.

A workaround:

  1. Create a new project.

  2. Record some audio or import audio that is 44.1 kHz it can be a mono or stereo track. I mostly have mono tracks.

  3. Import a stereo track that was recorded at 48.0 kHz

  4. Select the 48.0 kHz track by clicking the select button.

  5. Play that track to make sure it sounds correct.
    –< workaround >–

  6. Change the “Project Rate” (lower left corner of the main Audacity window) to 48000

  7. “Tracks menu > Mix > Mix Stereo Down To Mono”

  8. (Optional) Change the “Project Rate” back to 44100
    Note that the Project Rate sets the sample rate for exported files.


    Alternative workaround:

  9. “Tracks menu > Resample” and resample the 48 kHz track to 44.1 kHz

  10. “Tracks menu > Mix > Mix Stereo Down To Mono”

5

Second alternative workaround

  1. Create a new project.
  2. Record some audio or import audio that is 44.1 kHz it can be a mono or stereo track. I mostly have mono tracks.
    – note that the project rate is 44100 –
  3. Import a stereo track that was recorded at 48.0 kHz
  4. Select the 48.0 kHz track by clicking the select button.
  5. Play that track to make sure it sounds correct.
  6. “Tracks menu > Mix > Mix Stereo Down To Mono”
    – note that the sample rate of the mono track still reads 48000 when the track has actually been resampled to 44100; it gets shorter and plays back faster
    –< workaround >–
  7. In the Track dropdown menu, choose Rate, then 44100.
    – the track goes back to its original length and plays at the right speed

– Bill

6

Thank you for the replies. Glad to know that it is a bug and not a me problem :stuck_out_tongue:

-Ron

7

This has been fixed for the next Audacity release.