DBX 2031 Limiter

jlbass

What is a typical setting for the limiter for the DBX 2031? Plus, if I set the limiter to zero what effect would that have?

Thanks for your help! JL

Dra

Is this for speaker protection or individual inputs?

DRA

jlbass

This is for speaker protection

Dra

From a thread on PSW:

I set my limiters the old fashioned way:
What is the rated power (RMS) of the loudspeaker section in question?
How many Volts is that? Let's say it's 40V.
At what power do I want the limiter to come in?
How many volts is that? Let's call it 28V.
Then I :
Disconnect the loudspeaker.
Run a continuous signal (Tone) into the DSP until the Voltage out of the amp is 40V.
Adjust the limiter until the Voltage has been reduced to 28V.
Repeat for each section of the loudspeaker (using the appropriate Voltage for each section).
Save the settings as a preset (and save a copy).

Release time should be in the neighborhood of 8 times the attack time. If you don't have a watts to volts calculator, let me know and I'll figure it for you.

DRA

Gadget

That's all fine and dandy until you realize that this is a one knob limiter.. that it's PEAK STOP NOT brick wall... AND takes no part of gain structure into account...

1. Do you practice gain structure with your system?
2. Peak stop limiters let transient peaks through... the harder you hit them the more gets through... AND the higher the duty cycle becomes on the amps... which WILL harm your speakers...
3. If you set your limiter @ -0- chances are that you won't get any limiting action... gain structure dependent...
4. Your FAR better off to have a proper gain structure with 8-12 db of headroom and then if things merit it start to dial down the limiter till it just starts to see activity...this will help smooth a rough performance... dynamics wise...
5. DON'T depend on this for speaker protection :!: :!: :!: :!: :!: :!: :!: :!: it won't!
Gadget

Good advice for a full featured brick wall limiter though Dra... That hypothesis is of course for an amp with 40 volts of gain.. and a theoretical limit point as well...YMMV

jlbass

Thanks everyone, my speakers are two JBL MRX515 which I'm powering with a QSC PLX3602. They are rated at 400 RMS. DRA, I dont have a volt to watts calculator

JL

Dra

Ok. Here are the facts (math).
The amp will produce 775w @ 8 ohms / 79 volts AC. The amp will produce roughly double that when clipping.
The speakers will handle 400w / 57 Volts of continuous signal.
The check the voltage out of the amp set your multi-meter to VAC and connect to the binding post outputs. Be sure to set the gain structure like Gadget said before you start this process. And definately engage the Lo cut.
There are a couple of options for setting the limiter and depend a lot on your use and how much "self control" you have.
Limiting the output to 57v is the most protection IF you are loud enough AND the limiter is not egaging at all.
Limiting at 79v give little protection from clipping the amp, because it will shoot right passed.
75v is 700w might keep transiants out of the amp.
I would also engage the limiter on the amp and set the filter (33hz) on the amp as well.
The limiter is really for emegencies. Bad disconnection, dropped mic, out of control feedback, etc. The amp speaker combo is quite well matched as is.

DRA

jlbass

Thanks so much for your help! JL

jlbass

I'm back again, one last question. I'm running my system mono and the 2031 is my FOH EQ. I currently leave the gain level on the 2031 at "0". Is that correct? Sometimes I just don't feel I'm getting the maximum power from my system. As an FYI, my system consists of:

2 MRX515 - driven by PLX3602 (8 ohm each side)
2 MRX 518 - driven by PLX3602 (4 ohm each side)
DBX Driverack
DBX 2031
DBX compressor/limiter

Thanks for your help!

JL

Gadget

Ok, now you have opened up a world of questions...Why the 2231 when you have the Driverack? Instant gratification?
The 2231 sounds like crap compared to the Driverack...and why in the WORLD would you want to use the one knob compressor when you have a driverack? That makes NO SENSE whatsoever :?

I also see a compressor.. hopefully that's for channel insert use?

You need to detail how the system is hooked, and how the driverack is configured...

Have you read the "START HERE" thread"?
viewtopic.php?f=61&t=959
Or the FAQ's?
viewforum.php?f=60
These are in the "READ ME FIRST BEFORE POSTING SECTION"

This whole thing is VERY strange...
G

jlbass

Gadget,

As far as my DRPA is concern, I run a mono system, The crossover is set to 1X3 and my subs are set at 45hrz - 80hrz and the tops are set 80hrz. Both filters are set at LR24. My gain control is set at 0.

When I first purchased the DRPA I followed your gain structure setup you posted and updated it when I purchased a MixWiz 16.

The reason I don't use the EQ in the DRPA is that I'm constantly doing sound in various size clubs that are always packed with people and I'm never able to EQ the system to get a proper RTA measurement. This is why I use the 2231 where I can quickly EQ the room and adjust when needed.

Finally, my compressor is only used for line inserts.

If you have any suggestions on how I could enhance my setup and eliminate the 2231 and use the EQ on the DRPA is appreciated.

JL

Gadget

I hear you about the tactile advantage of the outboard eq... but fact is ... it's not a very "musical" eq...

Did you ever set up the speakers with a flat preset? We have found that if you flatten the response of the speakers you will have a system that is pretty darn good in most rooms with minimal additional eq needed. Do you really find that you need to do a lot of eq in the rooms you play in?

Further I posted in the FAQ section a "whole system" compression scheme for the driverack platform that will, when properly set up, provide gentile peak compression with little artifact and audibility...

Why do you have a 2 way system set up with a 3 way crossover?

What type music do you play?

Best regards
G

jlbass

Gadget,

I don't do a lot of EQ adjusting at show. I start out every show with my EQ flat and make minor adjustments. If you could help with how I can set the DRPA with a flat preset would be great.

Regarding your question regarding a 2 way system set up with a 3 way crossover, this is the way dbx instructed me to set up my system. Once again, any help you can provide to adjust this properly in the DRPA would be appreciated.

Finally, I perform in a blues/classic rock band.

I appreciate all your help and I will check out your FAQ whole system compression scheme.

JL

Gadget

If you want to get the most out of the system you need the measurement mic... got one? With the system you have you should only need a 2X4 Or 1X2 in your case... you could actually set up a mono 2 way and a single monitor feed with the one DRPA.. I'm working on an FAQ now for the DRPA+ to do just that...

G