Cannot export mp3 MONO?

When I try to export a mono track as mp3, the options has joint stereo and stereo but no mono.
How do I export it as a mono mp3?

Both audacity (1.3.14 beta) and lame (3.99) are downloaded today.

If the Audacity Project is entirely mono, then the exported MP3 will automatically be mono without you needing to do anything.

I opened a mono .wav file, and I still cannot export it as a mono mp3. I looked all over in preference and there is nothing that lets me specify the project is mono or stereo.

It shouldn’t be this difficult. Could someone give me a hint?

I finally figured it out.

The mp3 options channel mode is misleading. Even though it says “stereo”, it will (can) eventually export a mono file.
If the “use custom mix” options is turned on in file>preference>import/export, an advance mixing option dialog will pop up before the file is saved, and you can verify the file will be saved with 1 channel (i.e. mono).

I wish the UI is more user friendly, but I’m thankful the functionality is there.

We’re always interested in ways to make the user interface more intuitive.

  • The “joint stereo/ stereo” options refer to the “channel mode” command that Audacity sends to LAME (which encodes the MP3).
  • Lame only uses that command if the audio is being exported with two channels.
  • If Audacity is sending single channel mono for encoding, then LAME ignores the channel mode instruction.
  • The settings in the MP3 options control all subsequent MP3 exports until the user changes the settings. The “channel mode” instruction can’t be “greyed out” when exporting a mono track because if the channel mode option is not set then LAME will not know what to do if the next file to be exported is a stereo track. The MP3 options do not only apply to the current exported file, they apply to all exported MP3 files.

The MP3 options screen currently says:
Channel Mode: [] Joint Stereo / [] Stereo

What do you suggest that it could say that would make it clearer?

When the user exports a file and sees an option dialog, he will assume those options apply to the file he’s exporting.

How about forcing the user to see the mp3 options dialog everytime he exports an mp3? This way, you can tailor the options dialog to the file he is exporting. The option dialog could include these settings:

mono/stereo/joint stereo (radio buttons)
sampling rate: (drop down list and/or direct numeric entry)
bit rate: (drop down list and/or direct numeric entry)

With this approach, you can add some helpful error handling:
If the user has 1 mono track and he chooses stereo, audacity can tell the user to duplicate his mono track first. Or, audacity can offer to duplicate the track and save it as a stereo file for the user.

If the user has a stereo track and he chooses mono, audacity can ask whether the user wants to save the left channel, right channel, or a mix of the left/right channel. Or, just simply display a message telling the user to select a mono track first in order to save it as mono.

I see the sampling rate can be set in the project sampling rate box before entering the export dialog. However, exporting mp3 is when I most likely want to experiment with different sampling rate / bit rate combinations, so it is more concenient and intuitive to set the sampling rate in the export options.

Thanks for listening.

Thanks for taking the time to make a constructive suggestion, but I think that doing that would be widely unpopular. Many (probably most) users want the same export settings every time that they export. Adding just one more click in the export stage would almost certainly result in a lot of complaints about the inconvenience. Also, it would mean that “Export Multiple” could only be performed if all of the tracks were either mono or stereo and would fail if there was a mix of formats.

Perhaps just a simple rewording would help, for example:
Stereo Track Channel Mode: [] Joint Stereo / [] Stereo

It may also be helpful to add a “tool tip” that appears when the mouse pointer hovers over these settings with something like:

“This controls how the two channels of a stereo recording are processed during encoding.
Mono projects are not affected by this setting.”

Raising this old one up, as it touches the workflow we are working on right now.

There are 10-20 stereo clips in project. The exported file should be mono MP3. I assume the only way to mixdown to mono is to convert all stereo tracks to mono tracks - and leave the both halves to project as individual tracks. This is not the smoothest workflow imaginable. Some DAWs work like Audacity in a way that master bus channel mode defines the output file channel mode - but Audacity doesn’t have a master bus.

How about implementing the mp3 export options as below:

Channel Mode: [] Joint Stereo / [] Stereo / [_] Mono

Stereo content, stereo channel mode: Output - stereo MP3 file
Stereo content, mono channel mode: Output - mono MP3 file with left and right channels summed
Mono content, stereo channel mode: Output - stereo MP3 file with left and right channels having the same content
Mono content, mono channel mode: Output - mono MP3 file

Oh and any good reason why you are still using 1.3.14 - that is a superseded Beta version of Audacity.

Version 2 has been out for a while now (2.0.0 was heavily based on 1.3.14 Beta, with a few bug fixes) - 2.0.1 is the current release (soon to be replaced with 2.0.2). You can get the latest version from here:


E: I’m in a totally wrong category :smiley:
could this topic be moved to discussions about current version as it would be still valid there?

Done :slight_smile: