So I find myself commonly using Noise Reduction, Normalization, and Compression on, well, just about everything. My question is, which is the best order? I go back and forth on whether Noise Reduction of Normalization is the best first step. Compression, it seems to me, should go last.
The difference between theory and reality is that, in theory, there is no difference between theory and reality.
My two cents. In my view the first two steps are interchangeable IF you normalize all clips by the same amount. Personally, I would normalize first, then do noise reduction as you can hear the source audio better that way. If you don't normalize by the same amount, you'll end up having to adjust the noise reduction settings for every clip. Compression last is sensible, as if you put it earlier you will get a pumping effect on the noise that will make it more difficult to remove. Compression will add some variation to the noise level either way, but it is more controllable in this order.
This is the order I do my audio for film. I put effects in order of non destructive.
1. dc offset - offset power errors affects dynamic range so this goes first, a critical pre-alignment step
2. match volume - normalize 'peak amplitude' everything to -6db to see serious errors easier like clipping, offsets, phasing etc.
3. declip - run declip effect, remove buzzing with dynamics processing, notch filter the rest.
4. equalize - run parametric equalizer to reduce wind, hiss via freq cut, give vocal clarity 'D' curve
5. phase correct - once tracks layed, detect any phasing errors
6. noise removal - declick, de-reverb, remove hiss, wind, learn sound model/noise reduction, all else healing brush
7. studio reverb - to add vocal weight
8. RMS -23db audio - to roughly match vocals begin basic audio editing with levels(vocals center and 12db higher than music, etc.)
9. compression - multiband compress sfx: 4:1, vocals 2:1 db to give pleasing db range. always 2nd to last step because any other processes affect dynamic range. It should soft limit for you. hard limits are audible and not recommended.
10. quality control - match loudness ITU-R BS.1770-3 -23 LUFS film, -16LUFS youtube - for standard