Toggle Pre-Fader Metering – Logic Pro keyboard command of the day

  Toggle Pre-Fader Metering

Toggles between pre-fader and post-fader metering. The mixer visual changes with the meter to the left or right of the fader, left is pre-fader.

NB Pre-fader metering is post-insert – after all the plugins!

Set Pre-Fader Metering – Apple Support

The level meters normally show you the signal level after the channel strip volume fader. This is the most effective way to use the level meters during mixing your project. However, you can also set the level meters to show you the signal level before the channel strip volume fader, called pre-fader metering. You may want to use pre-fader metering when you want to adjust a signal using the controls on your audio hardware before recording.