When I first got to work with FCPX, I quickly realized there’re some audio enhancement features built-in. And while the Background Noise- and Hum Removal options are pretty self-explanatory, I was first intrigued by the third option – Loudness – and its controls: Amount and Uniformity.
It turns out, as Mark on this forum explains, those are just the “consumer” terms for something we know as compression threshold and ratio in the audio world.
So, for example, Amount at 20% sets compression threshold to -10db, 40% to -20db, 60% to -30db etc.
Likewise, Uniformity represents the compression ratio. Uniformity of 6% means 2:1 compression, 13% = 4:1, 16% = 5:1, 20% = 6:1, 26% = 8:1, 33% = 10:1 and 50% = 15:1.
Just so you know, don’t go too crazy on those numbers.