Yet Again - Limiter Settings

[SirNickity]

I'm having a time trying to visualise exactly your problem, but I thought I would toss an idea out there.

Have you checked that the limiter you're looking at is the one you're changing the setting for? On the DR, I think you have to press the comp/limiter button to cycle between global compressor and low, mid, and high limiters. (Also check that the compressor is off.)

This one caught me at first, as I was trying to find out why I could only set the limiters on one channel.

[yigba]

so I meter the output of the amplifier and adjust the High Xover level to obtain 40 volts. The limiter should be off while doing this.

This is exactly what I am doing by decreasing the xover by -8 db's in the DriverackPA. How much are you decreasing the xover in your unit?

[yigba]

And related to this topic - what are you guys averaging voltage wise in a live band siuation with 4 OTops (I'd only use 2 for indoor shows) and 2 24" T39's? Bar band - we mic everything - 3 vocals, keyboard, piano, guitar, acoustic guitar, bass and drums.

I mean if I'm not gonna get near 35 for the tops and 50 for the subs am I making a mountain out of a molehill in the first place? The biggest place we would ever play is outdoors needing to cover an area of roughly 60' by 150'. Most other places are small bars where I know having to push the volume won't be an issue at all.

[yigba]

I'm having a time trying to visualise exactly your problem, but I thought I would toss an idea out there.

Have you checked that the limiter you're looking at is the one you're changing the setting for? On the DR, I think you have to press the comp/limiter button to cycle between global compressor and low, mid, and high limiters. (Also check that the compressor is off.)

This one caught me at first, as I was trying to find out why I could only set the limiters on one channel.

I triple checked the limiters when I was setting them.

I guess my problem is that I don't want the limiters to kick in until I am at the top of the voltage range - 35 for tops and 50 for subs, with the amps wide open. And I want it to kick in when my fader on the board is at 0 (unity). I am not able to make this happen unless I dial back the amp gains which everyone here says is the wrong thing to do.

So my solution so far has been to dial back the crossover db's in the DriverackPA.

[doncolga]

And related to this topic - what are you guys averaging voltage wise in a live band siuation with 4 OTops (I'd only use 2 for indoor shows) and 2 24" T39's? Bar band - we mic everything - 3 vocals, keyboard, piano, guitar, acoustic guitar, bass and drums.

I mean if I'm not gonna get near 35 for the tops and 50 for the subs am I making a mountain out of a molehill in the first place? The biggest place we would ever play is outdoors needing to cover an area of roughly 60' by 150'. Most other places are small bars where I know having to push the volume won't be an issue at all.

The highest I've pushed my slim T30 pair is about 40 volts indoors. I've never measured my OT12 pair but I'm sure it's not anywhere near 35 volts. Having said that, I'd still be sure the limiter is properly set up.

[byacey]

My High Pass Xover level is set at -2dB. This setting will vary according to the input sensitivity specs of the power amp, and the output level of the mixer. Most balanced output mixers calibrated are either 1.0V, 1.23V, or 1.55V at 0 dB on the output buss meters. 1.23V is the common +4dB output level.

[tartan]

Did I just miss it, or was there no discussion in this thread about setting proper gain structure?

Why not do this the noise-optimized (minimized) way?

1) Disable x-over
2) Generate a sine wav in the passband of the speaker that you're working on.
3) Run up the output meter to the point where you'd like the limiter to start kicking in.
4) Set the limiter to start kicking in at this point.
5) While speakers are disconnected, measure voltage at amp output, and TURN DOWN the input attenuator ON THE AMP until you reach your target max voltage.

I used an EX-4000 to drive a stereo pair of SLAPROs this way. Obviously, that amp is WAY overrated for the SLA PRO, and with its attenuators set at zero (full up), the noise floor was insane, but the speakers were safely protected by limiters.

I actually LIKE full up at the amp, because then some monkey can walk by, turn the knobs all the way up, and my speakers don't blow. However, the noise floor is increased unnecessarily doing it this way. My solution for this customer? Security covers.

[Gregory East]

The "why not" was discussed. You leave yourself open to someone goosing the amp attenuator to get "more", winding up with silence instead.

Using the internal attenuators on the processors is the way to go if you want zero dB on your mixer to equate to onset of limiting. At least your mixer is running optimal gain and the amp is hopefully quiet enough to run wide open.

You can always turn your amp attenuators down and run the mixer harder when you're playing at lower volume. You lose a bit of headroom but you won't miss it until you want full volume and then you're off to the races with the amp attenuators.

[tartan]

The "why not" was discussed. You leave yourself open to someone goosing the amp attenuator to get "more", winding up with silence instead.

True, and that's why I said I prefer this approach, but only if the noise floor with the given speaker sensitivity doesn't become an issue. And for an installation, security covers solve that problem.

Using the internal attenuators on the processors is the way to go if you want zero dB on your mixer to equate to onset of limiting. At least your mixer is running optimal gain....

Quite right. No argument here. But I can still achieve that 0dB-at-the-mixer-output-onset-of-limiting in a noise-optimized way.

You can always turn your amp attenuators down and run the mixer harder when you're playing at lower volume. You lose a bit of headroom but you won't miss it until you want full volume and then you're off to the races with the amp attenuators.

I respectfully disagree. Whether I set the limiter by the two following approaches makes no difference to headroom, but it certainly does to dynamic range:
A) Set mixer output meters at 0dB; juice amp to 11; set limiter threshhold to speaker voltage limit, or down a few dB to play it safe.
B) Set mixer output meters at 0dB; set limiter threshhold to 0dB; juice amp to 11, then add amp attenuation until speaker voltage limit is reached, plus down a few volts to play it safe.

So what does someone do when he has a noisy, way-too-gainy amp, but it's what he has, so he uses it? He first decides if he can risk some knucklhead turning up the amp knobs, then he lowers the noise floor in case B, and boosts it in case A.

[Gregory East]

Yes, I misspoke. My way loses dynamic range.

If your gig is so quiet you can hear your amp hissing in the background you need to get a bigger audience or a quieter amp. I suppose if it is that quiet you don't have to worry about yahoos helping you out on the amp controls.

[tartan]

Yes, I misspoke. My way loses dynamic range.

If your gig is so quiet you can hear your amp hissing in the background you need to get a bigger audience or a quieter amp. I suppose if it is that quiet you don't have to worry about yahoos helping you out on the amp controls.

True! haha

My SLAPRO & QSC EX4000 (dual mono!) install were for the fellowship hall (50' x 70') of a church, which is used for public speaking, a/v presentations, and music, so the system had to be absolutely silent, and I had to repurpose amps they had. BTW, I still giggle when I think how the little QSC MX700 they had, running bridged mono driving a T48-36 corner-loaded destroys this particular room!

[gzc_stageTech]

I just use a noise gate to shut off any amp or system noise below the threshold. Nicely quiet when there's no input. And the compressor helps to corral the pastor when he starts to shout.

Chris