....Trained on FCP for many years... but new to FCPX
I was taught to mix dialogue between -6 and -12 dB, and of course never peaking above 0 dB. But this is assuming you are using a digital meter, which never exceeds 0. If i'm not mistaken FCPX now uses the dBU scale which goes into the positive range, and sort of depicts the average loudness as opposed to the instantaneous peaks on the digital (dBFS?) scale.
So my question is... what should my rules of thumb be for audio mixing now? About what dB level should my dialogue be set to, and what should my max peak be? I know there's new laws for broadcast, but I had some trouble deciphering it. Probably a little louder for internet i assume?
I'm not sure if I can help you because I'm fairly new to editing myself.
As you know the red coloring in the wave forms under the images are a good indication that the sound is too loud.
You will have to look from close up, though, to see *short* moments where the audio is too loud.
You can also play a clip and at the end check the two tiny indicators of the sound volume (on the right to the time code); when there is a moment of 'red' the indicator of that sound channel will remain red for the rest of that clip.
Important is not to use your ears, because when it's red the sound is often still good enough, but once you export it (at least when you burn it to a DVD) the parts where the wave form was red sound distorted.