Identifying Two-Channel Mono Recordings
When you are working with two-channel audio, it is important to be able to distinguish
between true stereo recordings and two tracks used to record two independent mono
channels. These are called dual mono recordings.
Examples of dual mono recordings include:
 Two independent microphones used to record two independent sounds, such as two
different actors speaking. These microphones independently follow each actor’s voice
and are never positioned in a stereo left-right configuration. In this case, the intent is
not a stereo recording but two discrete mono channels of synchronized sound.
 Two channels with exactly the same signal. This is no different than a mono recording,
because both channels contain exactly the same information. Production audio is
sometimes recorded this way, with slightly different gain settings on each channel. This
way, if one channel distorts, you have a safety channel recorded at a lower level.
 Two completely unrelated sounds, such as dialogue on track 1 and a timecode audio
signal on track 2, or music on channel 1 and sound effects on channel 2.
Conceptually, this is not much different than recording two discrete dialogue tracks
in the example above.
The important point to remember is that if you have a two-track recording system,
each track can be used to record anything you want. If you use the two tracks to record
properly positioned left and right microphones, you can make a stereo recording.
Otherwise, you are simply making a two-channel mono recording.