When you add plug-in effects to your tracks in Pro Tools (EQ, compression, reverb, etc.), your computer needs a little bit of time to process the tracks through the plug-ins. This processing is also not instantaneous. In relation to the other tracks in the Pro Tools session, the track literally plays back a little later than when it was originally recorded. That means, the tracks are no longer time-aligned.
To solve this issue, you can utilize Pro Tools’ Automatic Delay Compensation (ADC). ADC figures out what track has the most delay caused by plug-in processing (including the small amount of delay caused by using busses in your signal routing), then automatically delays every other track to match up with the longest delayed track.
For instance, if your largest amount of plug-in delay equals 1000 milliseconds of delay, then a different track having only 10 milliseconds of delay will actually be delayed an extra 990 milliseconds to align with the other track, so they both are delayed by 1000 milliseconds.
There are several settings for ADC in Pro Tools. Watch this video from the Pro Tools 10 Essential Training course to hear more about the differences between the offered ADC settings.
During a mixing session is usually the time when you’ll need the largest amount of ADC. You’ll likely have plenty of plug-ins that will be causing various amounts of delay on different tracks. Watch the following video to see how to implement Automatic Delay Compensation best in a mixing session.
For more training on Pro Tools, check out Pro Tools 10 Essential Training. If you’re interested in learning more about audio in general, I recommend checking out our Foundations of Audio courses that include our innovative Get In The Mix Pro Tools session files (no Premium membership required!).