BillFitzmaurice.info

When we limit BFM cabs is the voltage we're limiting to a peak setting or a RMS setting?

I just got a BSS FDS-336 that has a two step limiter - one is at the threshold you set (which I believe is RMS) and the other (brickwall limiter) is 6 db's higher.

I assume I'd set the limiter at the RMS of the speaker but don't know if the limited voltage per the BFM plans are RMS or peak.

RMS, PMS, MSNBC......none of those are relevant in setting your voltage.

Use a voltmeter attached to the outputs of the amp. With the amp all the way up, sent a test tone through your system where the main output is just below hitting the red.

Now, use your DSP device to limit the signal until the voltage reads whatever you want it to. Then throw the master fader all the way up - if the volt meter doesn't move - then it is working.

So say I want to limit the voltage to 40 volts all I care about is setting the threshold of the limiter so the reading at the max signal out of the mixer is 40 volts, correct? If so I have been making this way harder than it should have been.

yigba wrote:So say I want to limit the voltage to 40 volts all I care about is setting the threshold of the limiter so the reading at the max signal out of the mixer is 40 volts, correct?

Nope....the voltage from the power amp is the voltage that you are concerned with....not the mixer.

If so I have been making this way harder than it should have been.

Yep

Bruce Weldy wrote:Nope....the voltage from the power amp is the voltage that you are concerned with....not the mixer.

I get that. I just mean with all the gain settings the same in the DSP and the amp knobs wide open then the max out of the mixer drives the power amps to a specific voltage that you set by the limiter. So those voltage settings are the peak voltages that Bill wants his speakers to see. That's what I thought but just wanted to make sure.

yigba wrote:

Bruce Weldy wrote:Nope....the voltage from the power amp is the voltage that you are concerned with....not the mixer.

I get that. I just mean with all the gain settings the same in the DSP and the amp knobs wide open then the max out of the mixer drives the power amps to a specific voltage that you set by the limiter. So those voltage settings are the peak voltages that Bill wants his speakers to see. That's what I thought but just wanted to make sure.

Just wanted to make sure that you knew in which end to stick the thermometer.

Thanks for your help. This stuff just fries my brain.

But I will say this BSS FDS-336 limiter behaves the way I expected it to behave. I can't say the same thing about the Driverack PA limiter.

yigba wrote:Thanks for your help. This stuff just fries my brain.

But I will say this BSS FDS-336 limiter behaves the way I expected it to behave. I can't say the same thing about the Driverack PA limiter.

Never had a problem with either of the two driveracks that I use. They have held firm every time that I've tested 'em.

Maybe the limiter on mine is screwy. I posted here before - Either I could never get it to the voltage I needed at a usable setting on my mixer without turning down the amp knobs or it limited too much. I set it very similarly to this BSS unit.