distortion as they reach the last few dB's of headroom on each channel. By running the channels a little lower than 0VU when you PFL on the mixer the advantages in less distortion offset the relatively low signal at the A/D(input on recorder).Some transients will actually be higher than the VU/Peak meter will indicate.
I often track at -18dBFS and this leaves plenty of analogue and digital headroom. You may have a slightly lower S/N ratio in the analogue domain (i.e. the mixer) but if you are using something like a Mackie or better then this will be pretty much unnoticeable.
It surprises me when I see LED VU meters on live desk channels running at +15VU (1 LED before max) which occasionally ends up briefly clipping an A/D and probably has a sharp rise in analogue opamp distortion as the device reaches is operational limits.
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