Limiter vs Speaker Management

[nickb12345]

Hi All

 

One of my venues has come under some stick from the local authority for noise complaints and are likely to have to install a noise limiter on the PA. We have been discussing this with our usual supplier and they have sent a Formula Sound AVC-2 Limiter to demo.

 

I have been playing with this in the office today and looking through the paperwork (not had chance to run it up yet tho) but from the paperwork it would appear to function much the same to the limiter in most speaker management systems. We have Behringer Ultradrives in most of our venues and I have been looking at putting one into this venue for some time. I know the functions of this box well and understand the limiter function within it. Is this not the same as the function performed by the formula sound box?

 

I appreciate the AVC2 has locks and mechanical features to prevent tamper and bypassing the unit/changing the settings, but the Ultradrive has password protection too.

 

What’s other people's opinion on this one, do you think the limiter function of the Behringer box would satisfy the local authority's restrictions (subject to correct calibration and installation obviously).

 

Regards

 

Nick

[KevinE]

Firstly I assume you're talking an installed PA here rather than live music that would require a volume-sensing type of limiter.

 

Essentially the AVC2 works like an Ultradrive that is properly set as a limiter for sound control. This is not the same as an Ultradrive set incorrectly! Maybe that sounds like a daft thing to say but as a complex unit there's more to get wrong with the Ultradrive if you dont quite grasp the principles of the limiter and its parameters...we dont want it working like a compressor by mistake!

 

That said, there's no reason why it shouldn't be used for noise control providing it can be arranged so that the XLRs on the rear can't be unplugged and mated back-to-back thus negating its effect. Of course it should be set for a fast attack and slowest release and a fairly high ratio in order to emulate the AVC2.

 

The AVC2 is a dedicated unit for noise control (and loudspeaker protection) and is a very worthy unit, it has facilities for external warning lights as well as comprehensive, large built-in bargraphs for gain reduction, a long release time and a large wide ratio to make it as progressive and gradual as possible in its action. Their reliability and efficacy is proven and they're fitted in licensed premises all over the country.

 

So both will be ok properly installed and adjusted, you'll just have to speak to the council in question to see if they have any specific clauses about whether they need to see a closed-loop microphone-sensed type unit or not. (Formula sound of course do this drastic type as well!!).

[Matt Pengelly]

The AVC2 is a slightly different beast to the limiters in the DCX. It depends exactly what the scenario is as Kevin says.

 

Where the AVC2 comes into its own is in set-and-forget style bar/club installations where no engineer is present during the normal run of play. Whereas the limiter functions in the DCX will happily stop the odd peak nipping above the threshold, it won't be able to stop DJs from pushing as hard as they can to stay at that threshold all night right up to the point of something breaking or the council getting called out again. The beauty of the AVC2 is that once that pre-defined threshold is set, the more someone tries to push the levels past it the more harshly the attenuation sets in. Once levels are going way above the defined threshold the AVC2 will bring the level not only back to the threshold, but below it. I've found that it's a very effective 'stick' for keeping levels in check in that kind of situation.

 

If the situation is more along the lines of a live music venue, where there is always an engineer present then I would suggest that the DCX limiters (properly calibrated in order to protect the system - be conservative if necessary!) should be more than enough and then a simply asking the engineer to watch his levels. Anybody worth their salt should be able to do that.

 

Here's hoping you don't end up having to put in *one of those boxes that shall not be named*.

[nickb12345]

Thanks for the replies guys.

 

The situation is a install where the amps are in a rack I the dj box, so needs to be secure to prevent tampering with the front, but the back of the rack isnt accessable without taking everything out. Its a holiday park venue where there is 'operator' for running shows, but not neceserally a person who knows the ins and outs of live sound (sometimes not anything) - you wouldnt be able to rely on the operator to ensure levels are kept down, unless you have something simple installed that they can follow (i.e. the meter on the front of either of the above mentioned prducts (AVC unit would be the compression meter, the DCX unit would be the "Limit" led)).

 

I surpose it all depends how the limiter actually functions in the DCX unit. When the signal hits the defined level does it hit a brick wall and cannot go above that level, no matter how hard you drive the input signal?

 

Thanks

 

Nick

[J Pearce]

From memory, the DCXs limiter can have its ratio adjusted from brick wall to medium compression.

 

If you used the limiters on both the ins and outs you could get a compression then brick wall limit setup.

[Charlie Jeal]

The limiters on the DCX do't have an adjustable ratio at all ,you may however have been looking at the dynamic eqs 2nd page.

 

Charlie

[J Pearce]

Ah that'll be it. Has been a while since I've fiddled with the settings on mine.

[KevinE]

The limiters on the DCX do't have an adjustable ratio at all

 

Does the Driverack maybe?

[Charlie Jeal]

The limiters on the DCX do't have an adjustable ratio at all

 

Does the Driverack maybe?

 

 

Yes and no on the driverack pa anyway the limiters on them sound plain nasty when into heavy limiting and the lock isnt exactly foolproof to defeat on them.

 

The AVC2 is the best tool for the situation described as once it gets pushed past the set threshold it actually starts to attenuate the sound. The limiters on the DCX are mainly for speaker protection not volume limiting and are not as likely to be an acceptable solution to a local authority. Most EH noise enforcement people will recognise the Formula Sound name from the mains cut off limiters they also produce.

 

Charlie

[KevinE]

I agree on the AVC2 really, it's the best tool for the job if you dont mind the extra money.

[bryanmclean]

Hi, have you also considered the unit drawmer make? http://www.drawmer.com/products/protection...r-protector.php

 

We picked up one of these yesterday and had it up and running against the AVC2 at the lock up. The AVC 2 is brilliant as it actually turns the output level down when it hits its threshold of 0db which makes the dj aware that he has turned it up too loud and has to bring the output on the mixer down to bring the volume up on the dancefloor.

 

Now this in my mind is a perfect solution IF every single person who uses the setup is aware of what the box does and how to keep the volume on the dancefloor up. I have found that very few djs actually know how to use an AVC2 limited rig and the ones that dont get get confused by the large release time of the unit, they expect the music to go straight back up when the level is turned down, which is does eventually but not straight away.

 

The drawmer unit is different though, open the key lockable dials on the front panel, set the input signal level to the threshold you require then set the desired output level and lock the dials on the front panel for tamper protection. This unit differs from the AVC2 as it maintains the output level you selected from the threshold point you have set making it a bit more accepted by the dj community. They have only themselves to blame if the sound is distorted as that means they are clipping the mixer to hell even though it has no effect on output.

 

Just another option for you if you find the place doesn't get along with the AVC2. Can highly recommend both units though

[emsgeorge]

At a slight tangent from the above - Ive found that DJ's can be quite inginuitive when it comes to bypassing the AVC.

 

The AVC unit (formula sound) was found one week disconnected, but still in the rack. As we only serviced the site every couple of months, it was only the alarming regularity in which the bass cones were being fried at that made me look a bit closer.

 

If you want to protect it from prying 'dj' fingers - then dont use any of the simple tamperproof screws.

 

I found the best to be 'system zero' screws, which are available in M6 machine versions from RS. Virtually tamperproof, and quite difficult to remove if you dont have the right tool.

 

Also is not in the usual packs of 'security screws sets' from Maplin and the like.

[djmatthill]

At a slight tangent from the above - Ive found that DJ's can be quite inginuitive when it comes to bypassing the AVC.

 

The AVC unit (formula sound) was found one week disconnected, but still in the rack. As we only serviced the site every couple of months, it was only the alarming regularity in which the bass cones were being fried at that made me look a bit closer.

 

If you want to protect it from prying 'dj' fingers - then dont use any of the simple tamperproof screws.

 

I found the best to be 'system zero' screws, which are available in M6 machine versions from RS. Virtually tamperproof, and quite difficult to remove if you dont have the right tool.

 

Also is not in the usual packs of 'security screws sets' from Maplin and the like.

 

 

Hi There,

 

From Experience :( The System Zero Screws can be easily opened with a pair if small Side Clip wire cutters VERY easily..

 

I Worked in a venue a few years ago that used that system but I did nt have the correct tool, So I used my side cutters,, Worked Every time.....

 

A better way is get a some metal threaded wire (same stuff that used for security chain) and faster each corner in to the rack .....or a tamper proof seal similar to the ones they electricity and Gas board use on their meters...... you can tell Instantly if the units been tampered with........ of course all of the above is useless if the DJ can turn turn the rack around and get access to the back and simply un plug the XLR`s from the back of the AVC.........

 

Thats when you have to consider sealing the bvack of the unit somehow... One method I have seen is the original XLR sockets removed from the unit and replaced with some Non standard multipin connector is D type connector so if its unplugged it cant be bypassed,,,,,, or you could Hard wire a connection in and out of the AVC or...... if you ve got loads of money buy a soundweb that uses the Pheonix connectors B-) ...... Just my 2p`s worth ,,,, I also work as a DJ you seen,,,,, ** laughs out loud ** been there got the T shirt

[emsgeorge]

It would seem although the 'dj's' we have on the south coast aren't as inginuitive then - and in the end, we sealed up the rack good and tight. The system zero screws are better than most in my experience, and we use the driver bits with the old battery drill to make sure they are nice and tight.

 

We ended up putting security covers over the front of all of the amps, and vented panels all over the back of the rack. They seemed to get the message after that.