Sound coming out of only one speaker

Question

I'm in the middle of editing a movie, and I've run into a little snag with the audio.
I'm using an audio file I recorded in GarageBand, turned into an mp3 in iTunes, and then dragged into iMovie. The file plays out of both speakers (in mono, but I'm not picky) in GarageBand and iTunes, but once it gets to iMovie, it only plays out of one speaker. I feel like this should be fairly simple to fix, as the audio doesn't even have to be extracted from a video clip as it's already an .mp3. But for some reason I'm stumped. Any suggestions?
Thanks a lot!

Answer 1

"..two-channel mono directly from the camera (for which I often use a Sony on-camera gun mic).."
Twits.. (?!) ..various mics do produce mono, and sometimes on one channel only - e.g; left only - when plugged into a camcorder. Sometimes add-on Sony 'gun mics' may give only one channel if the contacts aren't properly touching on a Sony 'intelligent' hot-shoe (..the shoe which grips a Sony add-on mic).
Using Sound Studio (..see above..) you can easily copy, say, the left channel's mono audio onto a soundtrack's right channel (..tho' it'd still be mono: same thing out of both the left and right speakers..) so that the sound is there on both left and right.
To do that, just 'extract' the audio from the relevant video clip(s), double-click the extracted tracks to see what iMovie calls each of them (..probably 'Voice 01', 'Voice 02', etc..) then open your 14-days'-free-use download of Sound Studio and use 'File' and 'Open' to navigate to your extracted audio file, and then Select, Copy and Paste the one channel to the other side, as shown here.
[..To get to your extracted audio file(s), navigate to 'Movies', then within that should be the name of your particular movie, then open that movie folder and go to 'Media' ..at least that's what it's called in iMovie 4: I can't remember how it's organised - slightly differently - in iMovieHD.. and there will be your 'Voice' (extracted audio) file(s).]
NOTE: do NOT look in the 'Waveforms' folder; that just hold pictures of the look of your audio files; it doesn't contain the audio files themselves!
When you've edited the audio in Sound Studio - or whatever other program you might use, like Audacity or GarageBand - just use File and Save, and the changes will immediately play in iMovie.
NOTE also: if your add-on mics have only mono mini-jacks (..a long metal 'shank' with a single separate contact on the end..) you can simply replace those with 'stereo' mini-jack plugs (..shank plus 'ring' and 'tip'..) - if you're handy with a soldering iron - by soldering together the 'ring' and 'tip' contacts of a stereo jack within that mini stereo jack plug. That feeds the mono signal to both the left and right channels, and should then solve all future problems.
[..Not the exact info you need, but these pics should show you roughly what I mean: ignore the RCA-plug pics, and just look at the mini-jack and socket pics to see the left and right contacts. Click on 'Start Slideshow' for bigger, easier to see pics..]