Page 100 of the manual talks about selecting the audio and selecting the audio monitor. Can any one tell me what this is for and does the setting have an effect on the actual sound.

It does not affect the audio recording.

It is useful only if you're playing back a tape that was recorded with four-channel audio. Since the XH series cameras can't actually record four-channel audio, chances are strong that you'll never have to change this setting. Leave it at the default position, Ch.1/2.

Thanks Chris. Your explanation is much better than what the manual offered. Much appreciated.