Stereo - All recordings, regardless of compression rate, will be encoded with dual channel, stereophonic sound - (default). Recordings under 24kbps may result in a 'mono' (single channel) recording.
Mono - You may elect to record with a single channel, monaurally. This option is generally selected at expense of sound quality and depth in order to reduce MP3 file size. You can select this option from Advanced in the Recorder settings screen.