Sometimes you’ll want to apply stereo processing to a mono audio file. In order to do that you have to convert the audio file from mono to stereo first.
Sony Soundforge
1. Choose Process > Channel Converter.
2. Then choose the Mono to Stereo – 50% preset, and click OK. If you used the 100% preset, for instance, the volume may end up being too high to apply any more processing.
Adobe Audition
1. Choose File > Open and load your audio file. Go to Edit > Convert Sample Type or press F11.
2. In the new window you have the possibility to select Channels: Stereo. Now click OK.
Adobe Soundbooth
1. Import your audio file and drag it to an audio track in your timeline.
2. Now select File > Save As, You will be shown this dialog box where you now must simply select Stereo under the Channels setting.
Steinberg WaveLab
1. Load the audio file via File > Open > Wave
2. Now select File > Save As and click on the button that displayes the sample attributes (Eg. Wave / Mono / 44100 KHz / 16Bit)
3. From Audio File Format window select Channel > Stereo. Click OK. Click Save (here you can save the file under a a new name also).
Apple Logic Pro
1. Load the audio file via File > Open.
2. Now duplicate the track you have by using the DUPLICATE TRACK button.
3. Copy the regions from the first track and go to REGION in the INSPECTOR area pan one track to left and one track to right.
Audacity
1. Open the audio file you want to convert.
2. Go to the Project Menu and click the menu item that says “New Audio Track”.
3. Press CTRL+A on your keyboard to select all
4. Go to Edit Menu and hit the duplicate menu item.
5. Click the drop down arrow that is to the left of the first section of audio data and select “Make Stereo Track”