Converting Mono to Stereo in Batch (after recording)


Im recording with my Mic but the sound just record in MONO (right channel), the left channel is ever clear.

I checked: preferences > Audio I/O > Recording choosing Channel=2(stereo) and all my Recording Devices but the problem persist. :cry:

I can do it manually going to: :smiley:

  1. Audio Track > Split Stereo Track
  2. Select the channel, copy n paste

I would like to do it Applying Chain, but the option “Split Stereo Track” its not available there even on the Menu.

Even that, I couldnt define any key combination to “Split Stereo Track” what would help, doing it manually.

I will be glad for any help,

Uh… Mics are mono devices.

Unless you have a stereo mic (which is actually 2 mics next to each other), you can only get 1 channel from it.

You should be recording in mono.

Copy and pasting 2 mono channels into a stereo signal doesn’t actually get you a stereo signal, it’s just a mono signal that takes up twice as much space.

Tks a lot!!! :sunglasses:

Hi, I know that copying a mono track into both sides of a stereo track doesn’t give you real stereo output but this is exactly what I want to be able to do in a Batch. I have a lot of mp3s that are mono and I want to listen to them with headphones. I’d like to be able to hear the audio in both sides of my headphones. How can I convert these files in batch? I have started doing this manually (importing the mp3, duplicating the track and then making it into a stereo file via the menu on the track pull-down, and then exporting the file back to an mp3) and it is taking a very long time. Any and all help is appreciated.



A mono MP3 should play through both sides of your headphones without any adjustment. Your media player should simply duplicate the signal to both channels.
Try downloading this 10 second test tone and see if it plays through both sides of your headphones. If it doesn’t then there’s something wrong with your playback set-up.

I’m using the stereo out on my computer. The file is being played in Amarok on a PC running Fedora Linux. The stereo line is split (using a converter) into two input channels that are connected to the right and left auxiliary inputs on my receiver on my entertainment center. If I use the headphone jack on my computer it plays in both ears, but the audio out keeps the two channels separate (ie one silent). I can’t use my headphone jack all the time because of the location of the jack, my 18 month old daughter would be pulling on the wire whenever I looked the other way. I was hoping that it would be relatively easy to convert them to dual mono “stereo” files. It is easy to do manually, but it is taking a long time because there are so many. I have almost mapped keyboard shortcuts for all operations, and would love to be able to write a script that could then be run as the batch process on all of the files. This is the first batch conversion that I am attempting to write and the available list of commands seems to be pretty limited. I looked in the help but there didn’t seem to be much there. Is there a tutorial that I could read on batching? Is it possible to use shortcut keys in the batch script or can we only use the commands provided?

Thanks for the help,


So the test tone that I uploaded for you, does it play out of one speaker, or both speakers?

The test tone plays out of only one speaker.

Then there is something wrong with your set-up. A mono mp3 should play out of both speakers.

I presume that stereo mp3’s play out of both speakers, which rules out a lot of possibilities.
Have you tried any other media players other than Amarok?

I’m guessing that it’s a driver, player, or codec problem, but there are other possibilities:

Thanks for the link, I was able to get it to play out of both speakers. I used kmix to turn on “stereo downmix” and it now plays out of both speakers. I have no idea what that actually does but it works for now. FYI, I tried the test tone in several different players and even in a couple of players after converting it to a wav file.

I’m still interested in setting up batches and I may try to do this conversion anyway for the experience. Is there a tutorial available for setting up batches/command chains? Is it possible to use shortcut keys/menu items or is it restricted to the commands listed in the select command dialog?

Thanks again for the help,


Cool, that’s saved you however many hours :slight_smile:

Batches can be quite useful, but there are a number of limitations.

You are restricted commands listed in the select command dialog (and there’s one or two that are not yet implemented, but I don’t remember off hand which ones they are).

Obviously, commands that require selecting specific areas of a file are not going to work as Audacity will not know which bit you want. For example, (if I remember correctly) using “Fade In” or “Fade Out” will be applied to the entire file, not just the beginning or end.

Also, commands such as “Amplify” will have the same value for each file in the batch, so if you want to amplify up to -0.5 dB, you should use “Normalize” rather than “Amplify”.

In terms of a manual / tutorial, this is the best I could find: