In article ,
Serge Auckland wrote:
It shouldn't be forgotten either that audio levels are still being
monitored with a standard BBC PPM which under reads by anything between
4 and 8 dB on very short-term peaks, so 10dB of headroom on digital
transmission is sensible.

I very much doubt anything goes to line without going through a
compressor/limiter, and all such things tend to remove the sort of peaks
that fool a PPM.

In spite of many attempts, I could never persuade anyone at either the
BBC or commercial operators to adopt a true-peak PPM, even one with the
same standard 1-7 scale. Those who tried it always went back to the
well-known and loved quasi-peak as it looked more like they were used
to.

Thing is that the ear can't really hear these short term peaks, so the
meter not reading them is no bad thing from a balance - if not engineering
- point of view.

I've got fast acting peak LEDs on the workshop PPM and they're on most of
the time. ;-)

--
*The average person falls asleep in seven minutes *

Dave Plowman London SW
To e-mail, change noise into sound.