Friday, February 6, 2009

Auto Input and Input Only Monitoring demystified (I hope :) )

Auto Input Monitoring versus Input Only Monitoring: These two monitoring modes have to do with how an audio track passes audio to the tracks output path when the audio track is record enabled. These modes can be toggled using the shortcut of Opt-K (Alt-K on PC), or from the Track Menu. On HD this can be switch on a track-by-track basis, in LE it is a global setting.
Let’s start with the easy one first, Input Only monitoring. When Pro Tools is set to Input Only monitoring and a track is record enabled, Pro Tools sends the audio that it receives from the input path on to the output path at all times, regardless of whether Pro Tools is Stopped, Playing, or Recording.
Auto Input monitoring is a bit more complex. In Auto Input mode, when a track is record enabled Pro Tools sends the audio that it receives from the input path on to the output path during recording and when the transport is stopped. When Pro Tools is playing back the existing audio material on a track is sent to the output path (if there is any audio). If no audio has been recorded on the track then nothing is sent to the output (so no sound will be heard from that track, not even the incoming signal).

A practical example of when to use each of the monitoring modes follows:
** Input Only: You are about to record a background vocal part into Pro Tools. You set up the mic and the audio track. However, you are not sure what harmonies you want to sing and need to sing along with the existing vocal a few times to work out the harmony. In this mode, the track can be record enabled and you will hear your voice even when you are just playing back (not recording the vocal).

** Auto Input: You worked out the harmony part and recorded it for the chorus (from the example above). However, on the second line of the Chorus you were a bit flat. Set Pro Tools to Auto Input monitoring, create a selection of the line that needs to be replaced, set the pre-roll to 4-bars (for example), and hit record. During playback (the 4-bars of pre-roll) you will hear the playback of your harmony, when Pro Tools gets to the line you need to replace it will start recording and you will hear yourself singing (hopefully on pitch this time) during recording. When Pro Tools reaches the end of the selection it will exit record mode and resume playback of the existing audio (at least during the post-roll time, if the post-roll has been set) otherwise PT will just stop (if not set to Loop Record mode, but that’s a topic for another post ☺ ).

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