Re: sine

[Guy De Bievre <guy.debievre@xxxxxxxxxxxxxxxxxxx>]

pure sine waves can be lethal for systems, you could say they are
acoustically inefficient (i.e. the level you perceive audibly is in
comparison to 'regular audio signal' much less, for the same amount of
'electrical level' running through the system), so one is easily tempted to
turn up the volume, because it doesn't sound 'loud'.
On the other hand pure sine waves can be acoustically very efficient when
it comes down to interacting with other sounds, just check out the works of
the one great sine wave virtuoso of contemporary music: Alvin Lucier.
So if you're thinking about using sine waves, ask yourself if you really
need the typical characteristics op pure sine waves or if the idea you have
can be achieved with a different type of wave or a different type of sound
alltogether. The guy at the desk will be ever so grateful.

guy


At 11:19 09/04/01 -0000, Julian Knowles wrote:
>Interesting... I did the mix for Pan Sonic here in Sydney and i can 
>appreciate issues to do with the inedequacy of the PA system in a 
>venue.. They need a really big, hugely powerful PA to really 
>potentialise what is happening (notice i didn't say 'loud'). The main 
>issue is that they use test signals at very high amplitudes, 
>particularly the oscillator. If it is set to full tilt @ 10Hz then 
>that is what you get... No fairy dust or smoothing... Its a pretty 
>scarey prospect from a live sound point of view.. I had a *very* 
>large Martinsound system in a moderate sized room with 600 people in 
>it and i had the system working to its absolute limit from 120Hz 
>down.. The opening of the show was a sine sweep down to subsonic 
>frequencies which had all my clip lights on the crossover rack go 
>full red for the low frequency output.. I had to take some radical 
>action to avoid blowing the subs and the amplifier racks along with 
>them... It took  -12db full cut @ 100Hz down  to get the crossovers 
>out of clip... A kick drum would never ever do that... Totally full 
>on... never had to do that before..  Even when winding out the bottom 
>end to bring the system back into the safe zone you didn't really 
>hear a difference, as the frequency of the oscillator was so damn low 
>as to be virtually inaudible (but with incredible amounts of gain). 
>People near the stacks did say, though ,that they could feel the hair 
>on their arms standing up, so a lot of air must have been moving in 
>the room..
>
>i found that if you looked at their video oscilloscope it helped you to
mix...
>
>As for Ilpo and Mika, they are fine, but they are pretty particular 
>about how they sound which is fair enough, given the difficulty of 
>the signals they are dealing with. The only issue i had was that when 
>we soundchecked I had mountains of headroom in the system and 
>everything was comfortable - During the gig, though, they gave me at 
>least 20 db more of the oscillator which is what freaked the system 

doh, typical, thank god indeed for the guy who invented the compressor

>out..  I don't like compressing things too hard per se but a good 
>multiband compressor would have done a lot of the hard work to make 
>it sound good.