"Hard limiter" that lowers output as input rises?

The hows and whys of running sound.
Message
Author
User avatar
SoundInMotionDJ
Posts: 1749
Joined: Thu Mar 15, 2007 1:31 pm
Location: DFW, Texas
Contact:

Re: "Hard limiter" that lowers output as input rises?

#16 Post by SoundInMotionDJ »

byacey wrote:If you get the opportunity, attenuate your input levels so your limiters are just engaging when the DJ mixer is clipping. If it sounds like crap, it's his problem / responsibility to lower his gain to an acceptable level.
This is what I aim for.

The issue is that the DJs come in with a wide variety of sound interfaces with a wide range of maximum outputs. About 2/3 of the DJs are using the headphone out jacks of their laptop. Most of those are capable of +2 to +6dBu (ish). The other 1/3 are using sound interfaces that vary from the old consumer grade (-10dBu reference, maybe +4dBu max) to really hot sound interfaces with a +18dBu max output. My sound interfaces have a maximum +14dBu output.

That wide range of possible input signal levels means that when I set the system up to clip the DJ mixer and the final hard limiter at the same time....I have to choose if that will be with the lowest or highest input signal from the DJ. If I choose the highest input level, then most of the DJs really can't get loud enough. If I choose the lowest input level, then a handful of DJs can be way too loud. I typically choose near the lowest....in order to accommodate the headphone jack DJs.

I will say that when I am there to adjust the channel gain for them, this is a non-issue and works itself out in no time at all. Play a loud song, adjust your volume to the max, adjust the channel gain until it is just ticking into the yellow, and move on from there. It takes about 30 seconds for the song to kick in enough to adjust the levels.

The "talent" also have a tendency to blame the system and not their usage. The event owners want the talent to be happy....and I get stuck. After five years, all the real pros know to just trust me...but the wanna-bes have egos well in excess of their understanding.
10 T39S + 10 DR200 + 1 T48

byacey
Posts: 948
Joined: Thu Jun 14, 2012 9:09 am
Location: Edmonton, Alberta, Canada

Re: "Hard limiter" that lowers output as input rises?

#17 Post by byacey »

A simple in-line attenuator can take care of the guys that want to try and push +26db down the line; kind of like strangling a rooster that doesn't want to shut up.

For the -10db guys, you can remove the attenuator and make up whatever gain you need.
Built
T48s
WH8s
SX212

bmf
Posts: 115
Joined: Sun Aug 26, 2012 11:03 pm
Location: Muncie, IN

Re: "Hard limiter" that lowers output as input rises?

#18 Post by bmf »

Brent hit it on the head. The only way to stop a distorted signal from leaving the mixer is to loop in compression before it leaves the mixer through the main insert patch. Then set the knee at the yellow and smash the ratio so that if the DJ goes beyond it it drops the output like a rock. This will "teach" him to run his level where he should. If a "louder is better" DJ looses power when he turns it up then he won't turn it up. Cruel yes but very effective.

wallywally
Posts: 674
Joined: Thu Jun 21, 2007 7:20 pm
Location: Mount Airy, MD
Contact:

Re: "Hard limiter" that lowers output as input rises?

#19 Post by wallywally »

Setup a sidechain ducking compressor. Trigger set from the main output before the limiter. Set to engage 1db lower than the limiter. The signal to be attenuated could be the audio input or the main output. It won't be linear like you want but a 6 or 10db drop will get their attention. Set the attack at 500ms so transients don't trigger it.
Builds:
T-39
DR 280
Wedgehorn 8
Omni 12
SLA
TAT
TLAH experimental

byacey
Posts: 948
Joined: Thu Jun 14, 2012 9:09 am
Location: Edmonton, Alberta, Canada

Re: "Hard limiter" that lowers output as input rises?

#20 Post by byacey »

That will certainly work.
Built
T48s
WH8s
SX212

User avatar
escapemcp
Posts: 1219
Joined: Thu Feb 07, 2013 8:57 pm
Location: Bristol, UK

Re: "Hard limiter" that lowers output as input rises?

#21 Post by escapemcp »

Quick related question:

I have been testing my mixer to see the point at which it clips. I have used sine waves (as you can easily hear clipping with these) at various frequencies. If I can get my mixer to, say, +8dB when it clips (happens at the same point with all sine wave freqs), can I safely assume that I can take a broadband signal to +8dB without any clipping?

I currently HAVE made that assumption, and have soldered in some resistors into the XLR chain in order to reduce the levels going into the DEQ, so that clipping on the mixer happens at the same time as clipping on the rest of my kit. This keeps SNR ratio high and avoids any nasties from dropped mics, needle thumps etc.

Grant Bunter
Posts: 6915
Joined: Mon Nov 28, 2011 11:12 am
Location: Ilfracombe Queensland Australia
Contact:

Re: "Hard limiter" that lowers output as input rises?

#22 Post by Grant Bunter »

escapement,
Please note we have been talking about increases in distortion as well.
Sure, it might be the hottest signal you can get out of your mixer pre clip, but that doesn't mean it isn't distorted.
To determine that, you need to be on the non operator side and have a very critical and careful listen...
Built:
DR 250: x 2 melded array, 2x CD horn, March 2012 plans.
T39's: 4 x 20" KL3010LF , 2 x 28" 3012LF.
WH8: x 6 with melded array wired series/parallel.
Bunter's Audio and Lighting "like"s would be most appreciated...

User avatar
bjm362
Posts: 89
Joined: Sun Aug 31, 2014 5:55 am
Location: Oklahoma City, Oklahoma

Re: "Hard limiter" that lowers output as input rises?

#23 Post by bjm362 »

No matter how good the system, feed it a bad enough signal and it will sound bad. By giving your limiter that bad of signal they are doing two things. 1st they are STILL risking feeding square waves to your speakers and destroying them. Even limiters can be rendered useless when operated by complete idiots. 2nd they are proving they are complete idiots and have no business having their hands on the levels of any mixers.

While I do not recommend violence, I have to admit in that situation I would be awfully tempted to explain it physically (even in my decrepit physical state). I have run lights and/or sound at a number of Raves, though that has been many years. Even the ones where I wasn't the sound guy SOMEONE made SURE that did NOT happen!
In truth I don't think the headphone issue is the problem, I think the EGO issue is. Some of these guys seem to think if they can be the loudest then they are the best. Here that could encounter a different problem. There are limits now as to how loud an event can be to meet hearing safety standards. You never know when the sound police will pop in. They can write tickets and/or shut down the event.

Limiters and amps with good distortion detection are very useful. They can help dramatically extend both the life and level of enjoyment of your gear, but very few things are idiot proof!

It is your gear, do as you see fit! If you keep things at the right volume the audience can enjoy the show...if you do not the damage can extend to physical harm and lawsuits!
In order to have a dream come true, you must first dream it!

User avatar
Tom Smit
Posts: 7457
Joined: Sat Jan 05, 2008 1:24 pm
Location: Sarnia, Ont. Canada

Re: "Hard limiter" that lowers output as input rises?

#24 Post by Tom Smit »

bjm362 wrote: 1st they are STILL risking feeding square waves to your speakers and destroying them.
No.
"Square waves" just have more power under the envelope which is what burns out the drivers; it's not because the waves are "square".
TomS

User avatar
bjm362
Posts: 89
Joined: Sun Aug 31, 2014 5:55 am
Location: Oklahoma City, Oklahoma

Re: "Hard limiter" that lowers output as input rises?

#25 Post by bjm362 »

Tom Smit wrote:
bjm362 wrote: 1st they are STILL risking feeding square waves to your speakers and destroying them.
No.
"Square waves" just have more power under the envelope which is what burns out the drivers; it's not because the waves are "square".
You can create sufficient clipping prior to a limiter so that the limiter can no longer protect your drivers. That is the bottom line! Anyone operating a system that badly will at a minimum cause the system to sound bad. There is potential for them to cause it to be "game over" in the middle of a gig! I think we actually thoroughly agree that that is no fun!
In order to have a dream come true, you must first dream it!

User avatar
SoundInMotionDJ
Posts: 1749
Joined: Thu Mar 15, 2007 1:31 pm
Location: DFW, Texas
Contact:

Re: "Hard limiter" that lowers output as input rises?

#26 Post by SoundInMotionDJ »

bjm362 wrote:Anyone operating a system that badly will at a minimum cause the system to sound bad.
I am not worried about protecting the drivers. Well, more specifically, I have sufficient protection to the drivers that the shape of the waves or the amount of compression imposed by the hard limiter is not a concern.

The issue of "sounds bad" is trickier. I agree that it sounds bad...but I also agree that as you push into the limiter, it sounds louder. The peaks may not go any higher, but the RMS level will. And, there is a STRONG sense among the great unwashed masses that "Louder == Better". THAT is the issue that I am fighting.

A side chain compressor is in the ball park of providing the effect that I want...but at this point the test setup is overly complicated, given the hardware that I have on hand.
10 T39S + 10 DR200 + 1 T48

User avatar
bjm362
Posts: 89
Joined: Sun Aug 31, 2014 5:55 am
Location: Oklahoma City, Oklahoma

Re: "Hard limiter" that lowers output as input rises?

#27 Post by bjm362 »

Sound waves are not eminently benign. Too loud of continuous sound can cause headaches, fatigue, nausea, vomiting, hearing damage and in extreme cases they can cause brain damage and death.
Hopefully you are using your system in a such a manner as not to cause any of those. A DB meter is about $60, and it sounds to me like that is a vital piece of equipment in your situation! Apparently prudence is being disregarded at risk.
Don't let quantity of sound replace clarity of sound. It is a rocky road! If you need more gear to get the volume you need clearly, by all means build it. If you are already to loud and the sound is bad, turn it down until it is clear enough people can hear it better!
By your description you are being pressed at both ends...but the liabilities are all on you! I have done a sound gig where I did not stand up to the talent myself so I do understand. It rapidly became a nightmare I never want to repeat! The choices and responsibility is yours...Best wishes!
Last edited by bjm362 on Wed Oct 08, 2014 4:08 pm, edited 1 time in total.
In order to have a dream come true, you must first dream it!

CoronaOperator
Posts: 1648
Joined: Wed Mar 25, 2009 7:07 pm
Location: Medicine Hat, Alberta, Canada

Re: "Hard limiter" that lowers output as input rises?

#28 Post by CoronaOperator »

Another thing to try is the Dynamic EQ's on the DCX2496. Something like a low shelving eq @ 20khz, 12db/octave, with -15 dB gain or to taste, infinite ratio, threshold set just below your limiters kick in, and adjust attack to let shorter transients through, play with the release.

I haven't played with the dynamic EQ yet but I suspect it lowers the "gain" of the selected spectrum like an EQ rather than "compresses" the sound like a limiter. The low shelving @ 20khz will essentially lower the gain of the whole spectrum. If you want, lower the freq to about 500hz so only the bass drops when the threshold is overcome.

I suspect a hardware solution will never replace a soundman "riding the faders" but worth a try. I have 3 shows this weekend so If I have time I'll try it out and see how seamless I can get it or whether it is worth pursuing.
Built:
17" width 10" driver Autotuba
2 x 29" width dual Lab12 Tuba60
6 x DR250 2510/asd1001
In progress:
2 x DR250 2510/asd1001
For best results, point the loud end of the array towards the audience

Grant Bunter
Posts: 6915
Joined: Mon Nov 28, 2011 11:12 am
Location: Ilfracombe Queensland Australia
Contact:

Re: "Hard limiter" that lowers output as input rises?

#29 Post by Grant Bunter »

CoronaOperator wrote:Another thing to try is the Dynamic EQ's on the DCX2496. Something like a low shelving eq @ 20khz, 12db/octave, with -15 dB gain or to taste, infinite ratio, threshold set just below your limiters kick in, and adjust attack to let shorter transients through, play with the release.

I haven't played with the dynamic EQ yet but I suspect it lowers the "gain" of the selected spectrum like an EQ rather than "compresses" the sound like a limiter. The low shelving @ 20khz will essentially lower the gain of the whole spectrum. If you want, lower the freq to about 500hz so only the bass drops when the threshold is overcome.

I suspect a hardware solution will never replace a soundman "riding the faders" but worth a try. I have 3 shows this weekend so If I have time I'll try it out and see how seamless I can get it or whether it is worth pursuing.
I did suggest this on page one. But I wasn't sure if the OP has a DCX.
My understanding of the "usual" use of a dynamic limiter is to implement a narrow bandwidth limit over an offending frequency or set of frequencies, when that bandwidth presents itself as a problem when output goes up. An example would be almost like a feedback issue.

Since the Dynamic Limiter parameters can be set, you could activate it across the entire sepctrum...
Built:
DR 250: x 2 melded array, 2x CD horn, March 2012 plans.
T39's: 4 x 20" KL3010LF , 2 x 28" 3012LF.
WH8: x 6 with melded array wired series/parallel.
Bunter's Audio and Lighting "like"s would be most appreciated...

CoronaOperator
Posts: 1648
Joined: Wed Mar 25, 2009 7:07 pm
Location: Medicine Hat, Alberta, Canada

Re: "Hard limiter" that lowers output as input rises?

#30 Post by CoronaOperator »

Grant Bunter wrote: My understanding of the "usual" use of a dynamic limiter is to implement a narrow bandwidth limit over an offending frequency or set of frequencies, when that bandwidth presents itself as a problem when output goes up. An example would be almost like a feedback issue
... or one could also duck midrange (essentially increasing bass and treble) at low volumes and flattening out at higher volumes just like the old "loudness" button did to match the fletcher/munson equal loudness curves. Useful in an install. Or increasing the high frequency energy as the volume goes up with the assumption that volume increases happen when the crowd increases and hence absorption/refraction of high frequency energy goes up. My hope is that the dynamic EQ will leave the signal quality mostly intact. We'll see if the transitions are smooth when the content is bobbing up and down around the threshold. It may jolt/pump back and forth which would be horrible.
Built:
17" width 10" driver Autotuba
2 x 29" width dual Lab12 Tuba60
6 x DR250 2510/asd1001
In progress:
2 x DR250 2510/asd1001
For best results, point the loud end of the array towards the audience

Post Reply