Mini-Tip: Leave Extra Headroom When Mixing LiveSeptember 2, 2008 6:00 am Live Sound
Two things always seem to happen when an artist or band plays a bunch of songs at a gig:
2. They get faster as they go along.
I’m not exactly sure why these things happen, but I have observed them at many gigs. The tempo increase is a strictly musical matter, but if you are the sound man for the band you need to anticipate increasing volume and take it into account in your initial PA settings.
If you are lucky enough to have full metering on your mixer channels, you can adjust where the peaks of the signal on each channel fall with respect to the 0 dB reference point to provide yourself a little extra headroom. (Headroom is a measure of how much louder a signal can get at a given gain setting before clipping or distorting, not to be confused with Max Headroom, the fictional artificial intelligence.)
Normally, you would set the trim control for each channel so that the signal almost reaches 0 dB on the peaks with the main channel fader in the “0″ position. But, if you do this during a soundcheck (or more likely, during the first song), you will end up with a signal that will be too hot after a few songs, due to the inevitable increase in volume. So, my advice would be to set the trim control to provide somewhat lower peaks, perhaps -6 dB or so. You will still have to adjust the fader when the volume goes up, but at least the signal won’t clip.
[An expanded version of this Mini-Tip appears in my eBook, Cheap Advice On Live Sound.]Tags: live mixing, mini-tips, music technology -->