Which limiters are good enough?

Richard Stringer

Sophomore
Jan 13, 2011
124
0
16
Boston, Lincolnshire, UK
Now then guys, i'm looking for a limiter which is good enough for speaker system protection, I been looking at used limiters like the Drawmer DL241, Dbx 1066 and Drawmer SP2021, i've already got a Dbx 223SX crossover and BSS FDS-960 graphic equalizer. I heard that the Dbx Driverack PA aren't that great really and that the limiters in them aren't useless but they're not very good at all, so I was thinking about going an outboard dedicated limiter to be put in the signal chain before the crossover. The crossover will have a 1U mesh security plate over the front so after i've set it up no-one can mess with it, same with the limiter if I go for one. The amps are set to fully clockwise. I can't afford a used loudspeaker management system of the quality of say an EV DC One, XTA DP series etc..I can get hold of used limiters cheap enough though.
 
Re: Which limiters are good enough?

Essentially nothing analog will work as a peak limiter to avoid blowing drivers, since to limit peaks the ability to 'look ahead' in time is required. Something analog could work if you don't mind limiting early, losing headroom.

Fortunately, the most common failure mode of drivers is not mechanical (due to peak power), it is thermal (due to long-term power). A regular compressor/limiter can't provide long-term power limiting, since they reduce the dynamic range of the signal (which increases average power) rather than reducing the overall signal (while preserving the dynamic range).

In fact, I don't know of any processor that implements a decent average power limiter, except maybe the Lake stuff. The only average power limiters I know of are the ones in DSP amps, which doesn't apply to you.

I hope others chime in with their ideas so both of us can learn about other limiting options.
 
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Re: Which limiters are good enough?

Would maybe a Peavey VSX26 be ok? What's the unit like? Unless I get myself a pair of QSC RMX1450 amps and bridge them, one on each of my Peavey UL215H mid/highs, I mean I can get them cheap, about £150 each and they've got built in clip limiting haven't they. I haven't currently got an amp to power my mid/highs. By the way when I said I turn the amp's attenuators to fully clockwise, I mean that I do that with the amps, but they're hired, I don't own them.
 
Re: Which limiters are good enough?

So I guess then my best bet would be to just get a Dbx Driverack PA used and try and keep out of the limiters then yeah? Even though the limiters in it are pretty useless. Is the Peavey VSX26 any good? By the way would bridging two QSC RMX1450 amps, one per mid/high be good? I'm planning on doing that until next year when I save up for a pair of used Nexo PS15 mid/highs to replace my Peavey UL215H cabs, and then i'm planning on passively powering the PS15 cabs with a QSC PLX3402.
 
Re: Which limiters are good enough?

It sounds like you are missing the point. All of these pieces of equipment are PEAK limiters which does nothing for RMS heating. I would not buy the Driverack unless you need the eq/crossover functions as well.

If you are happy with your analog processing and crossover, by all means add an analog limiter, but understand the limits to the protection it will provide.
 
Re: Which limiters are good enough?

The easiest thing to do is to learn how loud your rig will get and keep it under that. There's no limiting like human limiting.© Then you can put a dominator on the mains to protect from accidental damage like mics dropped into monitor grills, phantom power pops, rappers, drunken party goers thinking it's karaoke night, etc......
 
Re: Which limiters are good enough?

Behringer DCX2496. Seriously. I've got 3 of these guys now and they are hands down the best budget DSP on the market. The limiters do their job, and they don't sound great when you dig into them, which is great because they pretty much tell you "hey, turn it down asshole." . They've kept my rigs safe to date.
 
Re: Which limiters are good enough?

I wish I could afford an XTA DP200, but although i'm gonna save up for one at the start of next year, I can't afford it right now.
If you go a year without limiters before having that XTA, I think you'll be fine. Just keep it out of the red. Seriously, it's that easy. PA's were used for the last 100 years without any limiters whatsoever.
 
Re: Which limiters are good enough?

Well I don't hammer my system hard but I do run it to the limit, by hammer I mean I don't ever run it so hard it's in the red, as soon as a red light flickers I turn it down a tad so to keep it at maximum without going into the red.
 
Re: Which limiters are good enough?

In fact, I don't know of any processor that implements a decent average power limiter, except maybe the Lake stuff. The only average power limiters I know of are the ones in DSP amps, which doesn't apply to you.

I hope others chime in with their ideas so both of us can learn about other limiting options.

+1.
I'm also interested in any products, cheaper than Lake, that do combined RMS and peak limiting.
 
Re: Which limiters are good enough?

Well I don't hammer my system hard but I do run it to the limit, by hammer I mean I don't ever run it so hard it's in the red, as soon as a red light flickers I turn it down a tad so to keep it at maximum without going into the red.

The question is, does the red mean anything?

You're probably safe not tapping any amp limit/clip lights, but you may be throwing away a lot of potential system performance. Perhaps you don't need every last ounce of output, which is an enviable position to be in, in which case keep doing what you've been doing. Since it doesn't sound like you've been toasting drivers, who cares what anyone else thinks?
 
Re: Which limiters are good enough?

Heres the deal. How good do you want the limiter to actually be?

I know that sounds stupid-but follow me.

Do you want the limiter to stop the speaker from "blowing". Then any limiter on the market can do that-as longas you set it low enough. Of course you won't be able to driver your speakers anywhere near the maximum-but at least you won't blow them up.

Do you want to be able to run your system up to around 99% and not blow it up? IF SO-then you are GOING to have to have a limiter that has all sorts of different "types" of limiting.

AND you are going to HAVE to know the exact limits of your speakers (and that will often not come off of the spec sheet).

AND you are going to have to know how to PROPERLY setup the limiter.

Now in reality-what you are looking for is something inbetween these two extremes. The "inbetween" is a VERY LARGE area-of all different types of limiters-different qualities and so forth.
For example-you should have a "peak stop-an RMS-a thermal/heating-an overexcursion-a HF feedback oscillation limiter and so forth. Most of those numbers you will not be able to get from the manufacturer-so how would you know where to set them? Carefull measurement is the way-but you hvae to be carefull not to tear up your loudspeakers in the process of "trying to protect them".

It is NOT and easy question-but the BIGGEST issues are NOT the particular limiters-but how well they are setup. This is based on your knowledge and skill and how accurate the specs are on the loudspeakers.

You can use the best limiters out there-but set them up wrong and they are worthless.

Setting limiters to get the most out of a loudspeaker-without tearing it up-is not an easy thing to do.

Just like building a bridge. Building a bridge to carry a specific load is pretty easy. Building it to "just barely" carry that load-is WAAYYYYYYY HARDER. Most people want to be able to run "right up to the edge" and not have a problem. That is very hard to do. So setting the limiter where it "kicks in" nice and early gives a better guarantee-but less overall output.

As will all things in audio-doing "really right" is often very hard. Kinda getting by-is much easier.
 
Re: Which limiters are good enough?

Thanks, I really apreciate all the help you guys have given me, any ideas on some pretty good limiter settings? I thought about these :

Attack Time : 1-5ms
Release Time : 100ms
Ratio : Infinity
Threshold : I turn that down until the amps stop clipping (when setting gain structure without a load connected to the amplifiers)
Output Gain : whatever number in db that the threshold has to be set to, so if the threshold is -10db (just an example) then the output gain would be set at 10db.

Is that right guys?