I found this on Page 107:
- If you’re using an external microphone, first attach it and use the sound pane of System Preferences to configure the input settings.
And that worked for me. The manual I was able to find, btw, is at; http://manuals.info.apple.com/MANUALS/0/MA662/en_US/Keynote09_UserGuide.pdf
But it may be for an older version, though it still helped.
THE AUDIO DIDN'T SOUND SO GOOD. In fact, somewhat pathetic. And I have a real good microphone that records wonderful in other apps.
Right now WORKFLOW, I arrange slides in Keynote. Then I'm exporting the Keynote file as a QuickTime movie. That can be imported into Garage Band and I record the audio there, while watching the slides. This works okay.
I suppose it would be even better if using Logic....and Final Cut Pro....yet those are expensive upgrade. For $15 from App Store I got Piezo and I not only like it's sound quality but it is super simple. Open the app. Click the red button, start recording; no frills but a-okay sound.