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Crown XTI 2 limiter


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#16 joust

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Posted 21 June 2013 - 07:52 AM

Another note on Clipping indicators: Most amps monitor input AND output for clipping. The limiter circuit can limit (acting like a quick acting compressor) the output signal with minimum distortion; If Clipping is visible while limiter is functionnal, clipping may come from the input circuit! Of course, if the input signal is hot enough and not clipping the input circuit, Clipping may still occur at the output.

#17 loginov

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Posted 21 June 2013 - 08:31 AM

I have not received an answer to my main question, which related with speaker protection.


When the threshold is exceeded by the signal, my speakers get maximum power (for example: dbfs=0) !!!
When did threshold is exceeded by the signal???
What can point to it???

#18 joust

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Posted 21 June 2013 - 03:15 PM

Limiter indicators in SA and BM: My bad: No such indicators in either app. Only Clip, Ready and thermal indicators.
As for the previous post, could it be that the Clip indicators flash because the input is clipping and not the output?

#19 loginov

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Posted 21 June 2013 - 04:09 PM

I can't find signs when the threshold is exceeded by the signal, in SA and BM !
How can I calibrate PA, after load preset, in this case not understand ... :unsure:



Posted Image
Posted Image

Posted Image



Can you look at the pictures above and answer, the threshold is exceeded by the signal or not ??? :o
Riddle? ))))))))))))

#20 dakos

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Posted 22 June 2013 - 01:18 AM

I would like to first describe how the limiter works: When the threshold is exceeded on the output side of the amp for a longer time then the attack time, then the limiter engages and limits the amplifiers power to MAX_AMP_POWER-THRESHOLD for as long a time as the exceeded signal continuous, plus the release time.

Now for a real world example: If you need to power and protect a 200W RMS speaker that has 800W peak power, at 8 ohms, you first need to choose an amp that has about enough power output for the speakers peak power rating. For an 800W peak power at 8 ohms the XTi4002, which has 650W at 8 ohms is a pretty good match. Now we need to limit the amps RMS power to about 200W, so the formula for calculating is this:
10 X Log(P1/P2)
If we feed our data we get:
10XLog(200/650)= -5.11 dBfs
That's what you enter the limiter in the amp.
I know it's a bit complicated but that's always the case when you really dig into things :)

Also you need to allow long enough attack and release time to allow this limiter to function as an RMS limiter.

Also you need to remember you only protect the biggest driver in your cab and not all the drivers!!!

In edition to that I sent Eric from the SA forum a question about monitoring of the limiter action.
Avi