[linux-audio-user] mixing advice

[Joern Nettingsmeier]

Patrick Shirkey wrote:
> 
> What do you think is the appropriate way to set the levels for a 12
> channel mixing desk that is being sent to a stereo channel in another
> mixer desk?
> 
> Would you set lowish on the master out and the gain high on the stereo in?

no. in most cases, you would have the output stage at 0 db (which is
nominal operating level), and gain to match.
p.a. mixers often produce very loud output (i've seen 22 dbu), so watch
out what the input can handle.

in case you have to use a very long cable between the mixers, it might
be advisable to have the signal as loud as possible to minimize the
effects of picked-up hum in the cable. watch for distortion in the
inputs, though.

> For micing an acoustic guitar in a space with large active speakers what
> would be the best gain, equilzation and volume level to not have it
> feedback often?

put the microphone on stage, set up the p.a. (i.e. do basic eqing to
compensate room acoustics or weirdnesses of the p.a.) and open *all*
microphones you are going to use.
now tell people to get lost or shut up, plug your ears and raise the
volume carefully. you will get distict feedback at some frequencies.
ride the faders so that the feedback stays at a constant level, then
grab the eq and kill it (lower only enough to stop the feedback). now
increase the volume - another feedback frequency will take over. lather,
rinse, repeat, until the overall volume is what you need. some feedback
frequencies you already killed might re-appear at a higher volume - just
lower the eq band some more.

now ask the artist to sit on stage, hold the instrument in playing
position, cover his/her ears and continue the above procedure (the
presence of the guitar will significantly change the characteristics of
the mike, and the body tends to amplify some freqs as well.

don't overdo it. the louder, the lousier. often, clarity of sound can
more than compensate for a marginal lack of volume.

when you handle the gain carefully, no painful feedback should ever
occur, but it's very advisable to take precautions. use hearing
protection, tell the artists to do the same.
leave one hand on the mixer fader at all times if possible, or place an
assistant at the board who knows how to switch off all outputs.
DON'T TOUCH ANY SWITCHES DURING THE PROCEDURE. only faders, only gently.
if you do need to touch a switch, set the fader to zero first, no matter
how sure you are that this switch won't be a problem. make it a habit.
causing the stage crew a tinnitus is a CATASTROPHE. (plus, it's dead
embarrassing.)


-- 
Jörn Nettingsmeier     
Kurfürstenstr 49, 45138 Essen, Germany      
http://spunk.dnsalias.org (my server)
http://www.linuxdj.com/audio/lad/ (Linux Audio Developers)