Record Levels - what is +4dB / -10dB

abowyerlowe at abowyerlowe at
Wed Apr 24 19:43:57 CEST 1996

>0 Vu actually represents the highest value that can be stored digitally.  If
>the signal exceeds that level, it is clipped.  What happens is that the top
>of the waveform (the portion that exceeds that highest level) is cut off in
>a straight line.  This makes a most unpleasant sound!

On badly designed digital equipment, rather than clipping the top of the 
waveform, the signal will wrap around to -xxx, creating an *extremely* 
unpleasant sound!

>As mentioned, to allow some notion of headroom, some manufacturers will
>purposely set 0 Vu to be a couple of dB below the actual clip point to allow
>for unexpected peak levels.

I think the ADATs have about 14db of headroom on their meters...

Anthony Bowyer-Lowe. Audio Programmer @ Mindscape UK.
"I'm the midnight bomber, what bombs at midnight." - The Tick.

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