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Old 18th September 2019, 08:18 AM   #1
east electronics is offline east electronics  Greece
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Default PA and limiters

There is no easiest way to say that I have a system installed for a client and i dont have enough knowledge to set up the limiters correctly

I can give any information wanted to get some advice ....

Mixer is A&H which as far as i know includes compressor in the output
Drive rack is Behringer
Amplifiers are EV P3000 ( with limiters working and set up to slow for bass and fast for tops )
System is Two boxes 2*18 Renkus Heinz while the units inside are Sound King 600W @ 4R

to drive those since i have 4R load and two units per box with amplifier that doesn't operate at 2R i drive one box with one amplifier one channel for one woofer at parallel mode so power that is available for bass for every box is about 1250 per woofer 2500 per box

2 Tops are also sound king 2*15'+2' 2+1/2 crossed lower woofer is passive crossed without mids upper woofer is crossed with mids and 2' driver is passive crossed about 4K

Program played at this place is classic Disco music so bpm is about 120 most of the time ....

problems are at near 100% which for me is just before amplifier clipping bass is not enough that is weird since it seems that 5KW is applied for that, and tops are always above bass ....far above

Installation is convenient 2*18 lays on the floor horizontally Tops are above 1.20m upper than the sub and have a slight tilt internal for horizontal and a slight tilt for vertical

Distance between the stacks is about 4-5m and the club is about 400sq meters while this system is the main PA and should be more than enough for the dance floor area and around while for the rest of the club exist a peripheral system that is not active at the time of the tests to avoid confusion

so today for testing i would like to remove all limiters to ensure that the problem lays there IE wrong limiter setting ( attack and release )

been trying to add some delay to the tops to bring bass upfront times 4-10-30 ms seem to not be able to effect bass response

been trying to play with phase starting from 30-90 -180 degrees and still there was loss of bass not increase ...

I would like suggestions about the limiters

Thank you
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Old 18th September 2019, 08:53 AM   #2
JonSnell Electronic is offline JonSnell Electronic  United Kingdom
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A&H do not use compression in the output stage.
The correct way to limit is to use a dedicated limiter. The limiter is connected to the output of the amplifiers and a safe level is set. When the safe level gets near the knee point, the limiter compresses the drive to the amplifiers, this stops the speakers and amplifiers from damage.
This document will explain;
https://www.powersoft-audio.com/en/d...-limiters/file
I used a compressor that was also an electronic crossover for the power amplifiers.
Don't forget, if employed in an enclosed room or hall, use a single point sub/bass otherwise as you walk around the phasing between subs/bass will cancel in pockets around the room giving no bass in the pockets.
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Old 18th September 2019, 01:06 PM   #3
David Morison is online now David Morison  Scotland
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Quote:
Originally Posted by JonSnell Electronic View Post
A&H do not use compression in the output stage.
Any chance you're thinking of their traditional analogue products here?
The Qu and SQ series of digital desks certainly do have comps available on the outputs, and I'm sure the higher series wouldn't miss out on features present in these lower series.
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Old 18th September 2019, 01:22 PM   #4
JonSnell Electronic is offline JonSnell Electronic  United Kingdom
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What I mean is there is no way to compress the result from the amplifier feeding the speakers without a dedicated feedback system that adjusts the drive voltage to the amplifiers.
The SQ7 series has gated threshold and compression but not relative to the loud speaker drive, just a guess by the engineer driving the amplifiers.
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Old 18th September 2019, 03:25 PM   #5
conanski is offline conanski  Canada
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Quote:
Originally Posted by east electronics View Post
problems are at near 100% which for me is just before amplifier clipping bass is not enough that is weird since it seems that 5KW is applied for that, and tops are always above bass ....far above

I have a similar system, the simple facts of the matter are you will never be able to use the full output of the tops as they are capable of a lot more SPL than the subs. A general rule of thumb is subs must be capable of at least 10dB more output than the tops, some genres of music have an even larger bass boost than that built into the recordings so it's not uncommon to see a 2:1 or 3:1 sub-top ratio these days. My 215/218 system is currently configured with the mid and high output levels on the DCX at -8 and -11dB relative to the subs.
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Old 19th September 2019, 07:21 AM   #6
east electronics is offline east electronics  Greece
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well that become a longer story than i expected ....

John Snell

i will not agree with you while i think that what you say should be the correct way to do things
In reality since this is not possible you calculate a few things ....guess is not the right word for an Electronics Engineer and you set up your limiters a few db lower than your calculation to be on the safe side given as a fact that the total result includes enough power for the application .

Conanski

Indeed i will agree with you about the sub / tops ratio but remember that this is a Disco club plays 80's music where bass was not that thick like is in House music or RnB music .... So i might as well get away with it on the edge ....

In the bottom line equipment belongs to the client so there is not much i can do with that I can recommend 2 subs more but some one will have to pay for that.


I solved the problem that had nothing to do with limiters after all

DCX2496 belongs to the client always operated and programed with a laptop always left with global lock for safety and always with a copy of the preset on the laptop ...

In reality what happened was that the preset was something like 4 years old which we have been working on that in four years more than 40-50 times for small or big changes .

So it seems that presets of DCX 2496 do remember things from the past for reasons that i dont know and that makes the all thing very confusing ....

I was trigered by three things to look farther in to this
1-In the past I had 5 EQ points in this preset since last year and after last year's changes i use only 3 EQ points ....the existing left 2 presets even if clicked to be inactive still effect the result .I check where can i remove totally these two presets and i was not able to do so

2-In the first page where the system is presented with graphs appears that my subs are lower than my tops I checked every page to see why is that and i was not able to find out why all my settings was correct but the graph presented my subs far lower than my tops ...

3- Computing power dropped and it was far lower without adding new settings only trying adjusting the old ones ....


Then i had the idea to load a new fresh preset with the exact same settings with the old one at the first click sound was 100 times better stereo image was dramatically improved and the all thing played far more clear than before ....
At the first click there was so much power in the system that was already too much for this club ....

so it seems that presets can get dirty on a DCX 2496 Presets can rememeber things from the past and involve them in the result before you even think about it ...

I was also told that when computing power drops for any reason on these machines then latency changes and that will have a huge impact in the sound quality ....

My system is over powered 2X15"+2'' top crossed as described above with units Sound king which actually is an excellent manufacturer and produces very good products and in the past produced units for big names of the market can probably handle 500-600W clean watt .... A EV P3000 will produce 1250 at 4R

My subs are 4R 600W yet again EV p3000 will produce 1250W at 4R
So i have more power than my units can handle

So after the fresh preset there was so much power in the system far before any clip even appears on any amplifier ...That of course gave room for the limiter to apply and operate far before a clip appears on any amplifier ...

so i used a slow limiter for the subs with fast release and a fast limiter for the tops with a fast release .....

been trying to play with how much fast and it seems that i managed to reach a point that in any case the Dj over drive the system there is a loss in the impact but there is no breaks or distortion in the sound

So i am good ...

Thanks dear all
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