Gain controls in Final Cut Pro
Gain amplifies (or reduces) the signal by a specific decibel amount.
For information about adding the Gain effect to a clip and showing the effect’s controls, see Add Logic effects to clips in Final Cut Pro.
Gain knob and field: Set the amount of gain.
Phase Invert Left and Right buttons: Invert the phase of the left and right channels, respectively.
Inverting phase is useful for dealing with time alignment problems, particularly those caused by simultaneous recording with multiple microphones. When you invert the phase of a signal heard in isolation, it sounds identical to the original. When the signal is heard in conjunction with other signals, however, phase inversion may have an audible effect. For example, if you place microphones above and below a snare drum, inverting the phase of either microphone can improve (or ruin) the sound. As always, rely on your ears.
Balance knob and field: Adjust the balance of the incoming signal between the left and right channels.
Swap L/R button: Swap the left and right output channels. Swapping occurs after the Balance parameter in the signal path. The Swap L/R button is disabled when Mono is turned on.
Mono button: Output the summed mono signal on both the left and right channels.
Note: The Gain effect is available in mono, mono-to-stereo, and stereo instances. Only one Phase Invert button is available in mono and mono-to-stereo modes. In mono mode, the Balance, Swap L/R, and Mono parameters are also disabled. A separate Multichannel Gain effect is also available in surround channels. This features per-channel Phase Invert and Mute buttons, and Level sliders for each channel.