Audio Levels in FCP

Keep in mind that you're dealing with two levels when editing: gain and output. By default, all clips imported into or captured by FCP have a gain level of 0db. You can adjust the gain level +12db and reduce it to nothing. Of course, adjusting the gain level affects the output level as well.

Even though the gain level on clips may be the same, the output level can differ greatly. Say you capture two clips and drop them on the Timeline. Both will have the default 0db gain level but when you play them one may be at -6db on the meters and the other may be at -20db. You can raise the lower output level or reduce the higher output level or a combination of both.

You can also use the Modify->Levels menu and choose either an absolute gain level adjustment or a relative gain level adjustment. And you can make that adjustment to as many audio clips as you've selected (highlighted) on the Timeline.

You can also use the Dynamic Processor filter or the Compressor/Limiter filter to help control or reduce the dynamic range of the output levels.

But if there is a big difference from clip to clip you will most likely have to do some real editing clip-by-clip, with the goal of creating a realistic output and dynamic range (all sections of audio shouldn't be the exact same level unless you're outputting a test tone).

-DH