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limiting and put the amp @ full power

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sgarfa View Drop Down
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    Posted: 26 December 2017 at 4:33pm
hi, i need ad information about limiting ... i use my rig processed by a rcf dx4008 (a xilica) at 90% for techno music... having 3000w @4 homs par channel and an amplifier whit 44db of gain the amplifier ..i  set it at -1db (function one site limiter calc), i have 0 bass all the chains of the sound, traktor s4 - mixer-  gain in input and sub channel in the amplifier, but I noticed that the limiter in the processor was always on.. I finally gave up and lowered the gain at the mixer...
I do not use the amplifiers with the volume know to the maximum, it would be better to put the volume to the maximum and from the mixer to attenuate the bass until you work occasionally the limiter?
sorry for the maybe trivial question



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Post Options Post Options   Thanks (0) Thanks(0)   Quote app Quote  Post ReplyReply Direct Link To This Post Posted: 26 December 2017 at 5:10pm
There is no volume control in your amplifier. Google amplifier input sensitivity...
"what!?"
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Conanski Quote  Post ReplyReply Direct Link To This Post Posted: 26 December 2017 at 6:20pm
What speakers do you have connected to this amplifier?
Can they handle full output of this amplifier with this source material?
What mixer do you have?
The Funktion-One limiter calculator is based on the digital reference of 0 dBFS which is roughly equal to +18dB on an analog mixer, are you driving the signal this high?
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Post Options Post Options   Thanks (0) Thanks(0)   Quote sgarfa Quote  Post ReplyReply Direct Link To This Post Posted: 26 December 2017 at 7:10pm
hi to all, chain regarding the subs is this:
  1. native instruments  traktor s4 mk1
  2. Peavey PV 20 USB
  3. rcf 4008
  4. fp14000 clone
  5. 2x per channel 1x21 reflex with b&c 21sw150-8ohm
app is right about the amplifier input sensitivity... it is an undeclared data , I relied on the Voltage Clip Limiter set at 44 db, anyway i used another app from hornplans.free.fr... and it said me -3dbu ...
no no the gain it isn't too hight in the input led meter of the processor the light are always green







Edited by sgarfa - 26 December 2017 at 7:33pm
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Post Options Post Options   Thanks (0) Thanks(0)   Quote sgarfa Quote  Post ReplyReply Direct Link To This Post Posted: 27 December 2017 at 11:50am
anyway, which are in general the precautions to be adopted for a fine setting of the limiters...
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Post Options Post Options   Thanks (0) Thanks(0)   Quote charlysays Quote  Post ReplyReply Direct Link To This Post Posted: 30 December 2017 at 3:22pm
Originally posted by sgarfa sgarfa wrote:

anyway, which are in general the precautions to be adopted for a fine setting of the limiters...


Here is the easiest way to quickly find the limiter setting you need to stop the amp clipping..
Switch off any clip limiters on the amp.
disconnect the speakers.
Play either a song with a full range of frequencies or pink noise through the mixer.
Turn it up loud, clip the mixer a bit like most DJs like to do.
Open the gains wide open on your amp (with speakers disconnected).
It will probably be clipping now.
Bring the limiter threshold on your DSP down until the amp just stops clipping, then bring it down another 1 DB. Use a long release on the limiter, like 4 seconds. This will provide the best speaker protection.

This is a basic way to quickly set limiters to stop the amps clipping.

The next consideration for speaker protection is the liklihood of the amp cleanly overpowering the speakers. To this end, when playing compressed dance music, I just use an amp which has slightly more in watts RMS than the AES rating. I've done this for years and not had any issues even when DJs push into the limiter.

If I'm using an amp which could cleanly blow the speakers, I use the rule of thumb that -6db halves the power going to the speakers, so if I was running a 1000w speaker with a 2000w amp channel I'd just subtract 6db from its output band on the DSP.

There is a way of calculating this mathematically and getting an exact limiter setting which both protects the amp from clipping and the speaker from overpowering but I never learned it (hate maths) and so far over several years have not needed it.

Also you need to make sure you're running the right HP and LP filters. Over excursion is a real risk with stuff like dubstep especially if you're running lots of headroom (much more amp power than the speaker rating which is often advised but as above I don't do it) on the subs.


Edited by charlysays - 30 December 2017 at 3:24pm
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Post Options Post Options   Thanks (0) Thanks(0)   Quote DMorison Quote  Post ReplyReply Direct Link To This Post Posted: 31 December 2017 at 2:29pm
Originally posted by charlysays charlysays wrote:


If I'm using an amp which could cleanly blow the speakers, I use the rule of thumb that -6db halves the power going to the speakers, so if I was running a 1000w speaker with a 2000w amp channel I'd just subtract 6db from its output band on the DSP.

6dB would be half the voltage, not half the power.
When voltage is applied to a load it induces current in the load which is proportional to the voltage.
Therefore, half voltage results in half current too - resulting in the power being quartered, not halved.

In your example above, that would just mean you'd been a bit more conservative than you'd thought, which may not be a bad thing really. 
However, if you definitely wanted half power, you'd turn down 3dB rather than 6.

HTH,
David.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote charlysays Quote  Post ReplyReply Direct Link To This Post Posted: 31 December 2017 at 3:01pm
Originally posted by DMorison DMorison wrote:

Originally posted by charlysays charlysays wrote:


If I'm using an amp which could cleanly blow the speakers, I use the rule of thumb that -6db halves the power going to the speakers, so if I was running a 1000w speaker with a 2000w amp channel I'd just subtract 6db from its output band on the DSP.



6dB would be half the voltage, not half the power.
When voltage is applied to a load it induces current in the load which is proportional to the voltage.
Therefore, half voltage results in half current too - resulting in the power being quartered, not halved.

In your example above, that would just mean you'd been a bit more conservative than you'd thought, which may not be a bad thing really. 
However, if you definitely wanted half power, you'd turn down 3dB rather than 6.

HTH,
David.


Thanks for clearing that up ☺ so -3 is 50% power and -6 is 25% of the power. Great rules of thumb for avoiding overpowering speakers!
Being a bit more conservative is good when it comes to jbl lol
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Post Options Post Options   Thanks (0) Thanks(0)   Quote sgarfa Quote  Post ReplyReply Direct Link To This Post Posted: 02 January 2018 at 9:01am
Originally posted by charlysays charlysays wrote:

Originally posted by sgarfa sgarfa wrote:

anyway, which are in general the precautions to be adopted for a fine setting of the limiters...


Here is the easiest way to quickly find the limiter setting you need to stop the amp clipping..
Switch off any clip limiters on the amp.
disconnect the speakers.
Play either a song with a full range of frequencies or pink noise through the mixer.
Turn it up loud, clip the mixer a bit like most DJs like to do.
Open the gains wide open on your amp (with speakers disconnected).
It will probably be clipping now.
Bring the limiter threshold on your DSP down until the amp just stops clipping, then bring it down another 1 DB. Use a long release on the limiter, like 4 seconds. This will provide the best speaker protection.

This is a basic way to quickly set limiters to stop the amps clipping.

The next consideration for speaker protection is the liklihood of the amp cleanly overpowering the speakers. To this end, when playing compressed dance music, I just use an amp which has slightly more in watts RMS than the AES rating. I've done this for years and not had any issues even when DJs push into the limiter.

If I'm using an amp which could cleanly blow the speakers, I use the rule of thumb that -6db halves the power going to the speakers, so if I was running a 1000w speaker with a 2000w amp channel I'd just subtract 6db from its output band on the DSP.

There is a way of calculating this mathematically and getting an exact limiter setting which both protects the amp from clipping and the speaker from overpowering but I never learned it (hate maths) and so far over several years have not needed it.

Also you need to make sure you're running the right HP and LP filters. Over excursion is a real risk with stuff like dubstep especially if you're running lots of headroom (much more amp power than the speaker rating which is often advised but as above I don't do it) on the subs.

okok thaks a lot mr charlysays... the crossover point (the high pass in particular)are set conservatives to prevent overesxursion..the china clone amplifier working well, but i prefer to dont't stress it, (probably the datasheet are overestimated)...
 I try to use the first system that you have illustrated ... then I will let you know :) ... thank you and happy new year


Edited by sgarfa - 02 January 2018 at 12:20pm
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