Setting Amp limiters

J

Jared Koopman

Junior
Jun 13, 2012
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16
Colorado
So I know this is showing my inexperience but for the most part I deal with self powered gear most of the time.

The system in question has a pair of Renkus Heinz CFX151 speakers and a pair of Tannoy VX8M monitors all powered from a QSC PLD4.3. The only processing available is the internal dsp on the amp.

I am just looking for advice on properly setting up the limiters.

What spec sheet data am I looking for with the speakers?

http://www.renkus-heinz.com/cf/cfx151

http://www.tannoypro.com/#!Page=Product&Id=121.1545

Thanks for any help.

Jared
 
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Re: Setting Amp limiters

Mark Oakley said:
Here's what I use: http://www.poulpetersen.dk/Appn/gblimthc.html I'll set my limiters to engage .75-1 volt under the calculated threshold.

-Mark
Click to expand...
Setting the limiter a volt below
calculated
is not doing anything useful.

For example. If a loudspeaker is rated at 500 watts @ 8 ohms and you set the limiter 1 volt below "calculated" value-, then it will give you 0.14dB additional protection.

That is not anything to be concerned with. For higher rated speakers the difference is even less.

HOWEVER- if the speaker is rated at 1 watt , NOW the 1 V difference will be over 3dB difference-that is a big deal.

Setting the limiters a bit low is a good idea-but even thinking about 0.7 or 1V is not worth the brain cells or concern.
 
Re: Setting Amp limiters

...and Ivan delivers the goods once again! You're absolutely right: my Xilica DLP 4080 displays its limiter thresholds in dbu, so what I should have said was:

"I'll set my limiters to engage .75-2 dbu under the calculated threshold".

Thanks for the correction!

-Mark
 
Re: Setting Amp limiters

Mark Oakley said:
...and Ivan delivers the goods once again! You're absolutely right: my Xilica DLP 4080 displays its limiter thresholds in dbu, so what I should have said was:

"I'll set my limiters to engage .75-2 dbu under the calculated threshold".

Thanks for the correction!

-Mark
Click to expand...
Yeah-that is a completely different thing.

When you only have a single limiter-where it is set depends A LOT on how the system is used and by whom.

I suggest for a "set it and forget it" type situation-3dB below continuous is a good suggestion.

For a system that will be monitored by a knowledgeable/responsible person, setting it for the continuous rating could be a better suggestion.

Of course it also depends on the attack times etc.

For "real protection" you need a number of different limiters. Heating/powercompression-continuous-peak-excursion-HF level etc.

Of course most of the time, all of these are not available. So you have to figure out what is most important in a particular situation.
 
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