Perhaps using an expensive post house would be the best way to make sure audio passes tech evaluations on PBS redbook standards. But I passed American Public Televisions evaluation doing it myself with the "Orban" Loudness meter. Yes the meter is different than what is on the fcp timeline, or just about any other edit system meter.
The ITU BS.1770 meter is like the editing software's meter in super slow motion and gives lower readings. It is like an average of the last 5 seconds. I got my laptop out and put the free Orban Loudness Meter on it, made sure they were calibrated with each-other with a -20db tone, and mixed away. I did it little by little adjusting every little part. But Compression might do the trick. (Behringer uf0202 will give you line-in audio to USB and worked well for me)
Just make sure you do a -20db tone straight off the timeline, calibrate your output volume so that your "listening" computer reads -20db on the orban meter, and your ready to mix average loudness.
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