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Re: Max Voltage during Live Sound???
Posted: Fri May 22, 2015 2:03 pm
by DJPhatman
yigba wrote:Being that we're concerned with displacement killing the sub drivers moreso than any type of thermal meltdown
It is excursion that limits power. While a driver may be limited to 50V, it should not be constantly run up to 50V. If you are hitting 1/2 voltage and it is not loud enough, double the cab count, assuming everything else is working properly. Doubling the power gains 3dB, but increases heat produced in the voice coil causing power compression. Doubling the cabs gains 6dB, with no additional heat produced.
Re: Max Voltage during Live Sound???
Posted: Fri May 22, 2015 3:19 pm
by yigba
Thanks for the info.
Re: Max Voltage during Live Sound???
Posted: Fri May 22, 2015 4:52 pm
by Grant Bunter
yigba wrote:
Being that we're concerned with displacement killing the sub drivers moreso than any type of thermal meltdown I understand the limiting rationale but that is effectively cutting our average output in half. In order to get that output higher you should figure out the best way to compress the mix, but not too much so that you kill the dynamics. Then simply limit the peak voltage thereafter, which theoretically should allow the average to be higher because the peaks of the mix will be slightly compressed and lower.
IIRC, in Bill's sub designs, as an example, the lab12 reaches both Xmax and thermal limits at the displacement limit of 50V.
Current mixdown methods, by and large, in recorded music, nowdays have the end result compressed to the nth degree. So some compression in live mixing can't hurt in that regard, to up the average.
Still, it's a knife edge. Remember, in the plans, it talks about amp transients. Mostly, that's what you're trying to stop. Along with displacement limiting for any given driver...
Re: Max Voltage during Live Sound???
Posted: Sat May 23, 2015 3:23 pm
by yigba
And the transients are what drive me nuts. In live sound the kick drum is mostly the one channel that has those transients. The bass channel sometimes also.
I hate that I have to lower the overall volume just to deal with those transients.
Re: Max Voltage during Live Sound???
Posted: Sat May 23, 2015 4:59 pm
by Bruce Weldy
yigba wrote:And the transients are what drive me nuts. In live sound the kick drum is mostly the one channel that has those transients. The bass channel sometimes also.
I hate that I have to lower the overall volume just to deal with those transients.
Compressors on those two channels help. And knowing the player and what to expect.