Limiter Parameters (dbxV360) and bridge..

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GNUlars
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Limiter Parameters (dbxV360) and bridge..

#1 Post by GNUlars »

Dear BFM people!
I am finishing a 20" T48 with a Kappalite 3015LF 8ohm
I have a DBX Venu 360 and two QSC RMX 1450
I understand the threshold adjustment using a voltmeter and a sine wave (at 60-80Hz maybe?) But there are several other parameters.
What values should I use for Overeasy, Attack, Hold, Release and Overshoot?? Also: should i turn on the Auto button?
I know my amp is a little small, and you are not fond of bridge mode.
Should I go for just one channel and 260watts into 8 ohms or can I use bridge mode for more output with a single sub (800watts according to QSC specs).
I should get a more powerful amp but this is what I have right now...
Thanks
Lars
Making six or twelve DR200`s, great fun!
Also have two T39´, a T48, four W8´s and two W6´s in the making
No, I´m not in a hurry...
Allen&Heath GL2200 16ch, Allen&Heath SQ5, DBX Venu360, DBX dr PA

Bruce Weldy
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Re: Limiter Parameters (dbxV360) and bridge..

#2 Post by Bruce Weldy »

First.....are you sure you are in the limiter section and not the compressor section? I haven't used the 360, but on the other driveracks, you have to page past the compressor to get to the limiter.

There is no problem bridging that amp as long as you have the limiter set properly and test it properly. I've run three bridged amps for my 6 - T39s for years.....never blown a single driver.

6 - T39 3012LF
4 - OT12 2512
1 - T24
1 - SLA Pro
2 - XF210


"A system with a few knobs set up by someone who knows what they are doing is always better than one with a lot of knobs set up by someone who doesn't."

Bruce Weldy
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Location: New Braunfels, TX

Re: Limiter Parameters (dbxV360) and bridge..

#3 Post by Bruce Weldy »

Bruce Weldy wrote: Sun May 15, 2022 9:04 am First.....are you sure you are in the limiter section and not the compressor section? I haven't used the 360, but on the other driveracks, you have to page past the compressor to get to the limiter.

There is no problem bridging that amp as long as you have the limiter set properly and test it properly. I've run three bridged amps for my 6 - T39s for years.....never blown a single driver.
Just went and looked at the manual....more options with the 360. Turn the OverEasy and Auto OFF. Turn the Peak Stop Plus ON. Set the Overshoot as low as will go. Give that a try. That should be as tight as the unit can be on the limiter.

Most importantly is making sure that you set the voltage limit properly - if you have any questions about how to do that, let us know.

6 - T39 3012LF
4 - OT12 2512
1 - T24
1 - SLA Pro
2 - XF210


"A system with a few knobs set up by someone who knows what they are doing is always better than one with a lot of knobs set up by someone who doesn't."

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GNUlars
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Location: Jonsered, Goteborg, SWEDEN

Re: Limiter Parameters (dbxV360) and bridge..

#4 Post by GNUlars »

Thanks! I will give it a try.
Should Attack, Hold and Release also be set low?
I will try and post a picture of the editor window..
Screen Shot 2022-05-16 at 00.49.23.png
Making six or twelve DR200`s, great fun!
Also have two T39´, a T48, four W8´s and two W6´s in the making
No, I´m not in a hurry...
Allen&Heath GL2200 16ch, Allen&Heath SQ5, DBX Venu360, DBX dr PA

Bruce Weldy
Posts: 8301
Joined: Fri Nov 27, 2009 11:37 am
Location: New Braunfels, TX

Re: Limiter Parameters (dbxV360) and bridge..

#5 Post by Bruce Weldy »

Honestly, I don't care about those parameters. It's not a mixing tool like compression, we just want it to stop the voltage when it hits the limit - it's about protecting the speakers. If you are hitting the limiters all the time and are worried about how fast or show the limiting starts or stops, then you need to build more subs and back off the volume.

6 - T39 3012LF
4 - OT12 2512
1 - T24
1 - SLA Pro
2 - XF210


"A system with a few knobs set up by someone who knows what they are doing is always better than one with a lot of knobs set up by someone who doesn't."

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Seth
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Re: Limiter Parameters (dbxV360) and bridge..

#6 Post by Seth »

A couple things... do not use the method of setting gain structure as outlined in their manual. Doing so, will not protect your subs. Also, we've discussed this a little in the past, I think. I'm still a little surprised they don't have a standard Brick Wall Limiter option. They seem to have "Peak Plus "off"" as an RMS limiter, and "Peak Plus "on"" as a peak limiter with an adjustable overshoot... 2dB minimum and no option to have 0dB overshoot. So, it sounds to me that if you set your limit at 60volts, the limiter would allow voltage peaks of 75.5 to occur. And that to have 60 be the absolute max brick wall limit, you'd have to set the limiter for 47.7 volts.

It makes very little sense to me why they wouldn't have a traditional brick wall limiter. I'd almost say to use the compressor instead, except that it is way too early in the signal chain to do what we'd need it to do. Otherwise, it's settings could be made to work as a better limiter for our needs than what they call a limiter.
Screenshot (182).png
Build in process - 2 WH6, one Alpha 6a loaded, one PRV Audio 6MB250-NDY loaded

Two 2x6 shorty SLA Pro's
One T39, 16", 3012LF loaded
Tall AutoTuba, 20" wide, 2x 8" MCM 55-2421
TruckTuba, 8½" wide, 2x 8" MCM 55-2421

Bruce Weldy
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Re: Limiter Parameters (dbxV360) and bridge..

#7 Post by Bruce Weldy »

Seth wrote: Mon May 16, 2022 12:27 am And that to have 60 be the absolute max brick wall limit, you'd have to set the limiter for 47.7 volts.
You may be correct, but I don't set 'em with math - I'd use the voltmeter and the proper testing to determine if it holds - then adjust it down if it doesn't. I've never had a problem with my old driveracks overshooting when I set the limiters properly. At least not by more than a volt or two. But, the difference between 60 volts and 50 volts isn't that big of a deal either way. If you are hitting the limiter very often, you need more cabs.

6 - T39 3012LF
4 - OT12 2512
1 - T24
1 - SLA Pro
2 - XF210


"A system with a few knobs set up by someone who knows what they are doing is always better than one with a lot of knobs set up by someone who doesn't."

User avatar
GNUlars
Posts: 49
Joined: Thu Apr 17, 2014 2:26 pm
Location: Jonsered, Goteborg, SWEDEN

Re: Limiter Parameters (dbxV360) and bridge..

#8 Post by GNUlars »

Ok. Thanks for your replies!
I´ll give it a try with a voltmeter and see how it works out without worrying about attack, release and hold values.
So.... I can run sine wave through the mixer to set the gains at the same time, and after setting gains and limiter I suppose I should also try music content looking at the voltmeter and the gains...? Hope I got it right...
Thanks
Lars
Making six or twelve DR200`s, great fun!
Also have two T39´, a T48, four W8´s and two W6´s in the making
No, I´m not in a hurry...
Allen&Heath GL2200 16ch, Allen&Heath SQ5, DBX Venu360, DBX dr PA

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Tom Smit
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Re: Limiter Parameters (dbxV360) and bridge..

#9 Post by Tom Smit »

Pretty much. Do your testing without the speakers hooked up because if you try to reach said voltage with speakers hooked up, you would either potentially fry your speakers or your ears.
TomS

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Seth
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Re: Limiter Parameters (dbxV360) and bridge..

#10 Post by Seth »

GNUlars wrote: Tue May 17, 2022 7:00 pm Ok. Thanks for your replies!
I´ll give it a try with a voltmeter and see how it works out without worrying about attack, release and hold values.
So.... I can run sine wave through the mixer to set the gains at the same time, and after setting gains and limiter I suppose I should also try music content looking at the voltmeter and the gains...? Hope I got it right...
Thanks
Lars
Rereading my previous post... awfully negative sounding. Sorry about that. Completely not my intention. Just wanted to point out that functionality so you're aware of what's going on if you set it for one value, then get a different value when you test it. I'm pleased to read Bruce hasn't had any issues getting it to work as intended.

Anyway, standard run of the mill digital multimeters read voltage and/or frequency of single sinewaves fairly well. But, they do not measure music well at all. Don't be worried if you measure while playing music sources and get figures that are much different than what you measured with a sine wave. There's really no reason to measure voltage while playing music, can't get an accurate reading unless you have a high dollar true-RMS volt meter.

To set limiters, I use a 60Hz sine wave and a multimeter. All crossover and high pass filters disabled and speakers disconnected.

To set gains, with crossover filters enabled, I use a sinewave of the intended crossover frequency and a decibel meter. Run the subs alone, note the level, then run the tops alone and adjust to match the subs level. Then play them both together and the reading should be close to 6dB more than either on their own. I personally usually use Linkwitz-Riley filters between the lows and mids/highs. LR filters are -6dB at their designated frequency, so they sum to 0dB, no gain/attenuation at the crossover frequency. Some guys seem to like having a gap of 5-15Hz in their set frequencies. I assume this is a practice originating with the use of Butterworth filters, but that's just conjecture. There's certainly more than one way to get the job done.


Wiki - Linkwitz-Riley Filter
Screenshot (183).png
Build in process - 2 WH6, one Alpha 6a loaded, one PRV Audio 6MB250-NDY loaded

Two 2x6 shorty SLA Pro's
One T39, 16", 3012LF loaded
Tall AutoTuba, 20" wide, 2x 8" MCM 55-2421
TruckTuba, 8½" wide, 2x 8" MCM 55-2421

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