So I had a bunch of audio files in mono and wanted to convert them to sterero. This is pretty much just a case of copying the single-channel mono stream and pasting it into the two separate channels of the stereo track. I then also wanted to add a fake effect that makes this new dubious stereo track sound something like a genuine stereo track. All this is possible in Audacity. What's more, the program allows batch processing which allowed me to automate this task across a bunch of files.