Converting Dual Mono to Mono [SOLVED]

Using Audacity 2.0.5 and Mac OS 10.6.8

I use Fission to edit dual mono PCM audio in the AIFF file format. I’ve been using Audacity to convert the dual mono Fission created AIFF files to mono audio files ever since receiving help in this thread years ago: I typically work with AIFF rather than WAV files now. In my experience, the left channel on the source analog audio cassette tapes is typically louder than the right channel, and theoretically has a better signal-to-noise ratio. Therefore, I usually choose the left channel when creating mono audio files from my dual mono AIFF files, following the steps described in that thread.

However, now I have a case where I want to use the right channel for some of the audio because Audacity shows it as having less clipping than the left channel, and the left channel as usual for the rest of the audio. What are the best steps for combining my choices like this?
Screen shot 2016-02-19 at 5.07.07 PM.png

You could use envelopes to automate the mix.

Leave the envelope volume up for the channels you want to use, turn down where you don’t want to use it. That should give you a sliding transition between the two channels. See:

Put “split lines” at the points where you want to switch from one channel to the other (Click on the track then Command + i)
When you finished doing that, split the stereo track to mono using the track dropdown menu (

You can select an “audio clip” (the audio between two split lines) by double clicking on it.

Go through the tracks removing the parts that you don’t want to keep. (Quickest way is probably to just silence them with Command + L).

You should now have something similar to this (alternating sound / silent clips):
When you export, the two mono tracks will automatically be mixed together, but if you want to see the result before you export, select all (Command + A) then “Mix and Render” (from the “Tracks” menu).

steve’s suggestion works pretty nicely for me. I tried it, following all of the suggested steps, and it works for me. Thanks.