Many higher quality voiceover microphones record audio on only one (mono) channel, which requires some correction. However iMovie doesn’t have a built in mono to stereo or stereo to mono option.
The quickest and easiest way I’ve found to convert mono audio to stereo audio (although technically I’m converting stereo audio to mono audion) in iMovie 09 is showcased in this video.
Technically speaking, my voiceover microphone (a samson g-track) record in stereo, but only populates the left stereo audio channel. This means the sound only comes out of one speaker, the left speaker.
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