multichannel power amp- level control setup - diyAudio
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Old 24th March 2012, 02:19 PM   #1
panduro is offline panduro  Denmark
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Default multichannel power amp- level control setup

I have two five channel carver av-705x poweramps. all channels has their own level control.

I need their individual voltage output to macht eachother.

can i measure voltage output precisely? and how?

best regards

panduro
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Old 24th March 2012, 02:39 PM   #2
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Do you need to measure and/or adjust these outputs under dynamic or static conditions? E
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Old 24th March 2012, 03:02 PM   #3
panduro is offline panduro  Denmark
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thanks for answering.

That is a good question(because i dont know the answer...) static or dynamic, is that about load or frequency?

i think that static would be fine, just need to be sure that the different channels output same voltage matched in pairs. You know, left/right lf, left/right hf and so on, it would make it a bit easier to do active xover "design".

best regards

panduro

Last edited by panduro; 24th March 2012 at 03:04 PM.
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Old 24th March 2012, 04:28 PM   #4
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Static: Set and leave (supervisory)
Dynamic: Adjust on the go (compresssor/expander)

Each approach has it's own challenges and solutions. What is the application? E
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Old 24th March 2012, 04:44 PM   #5
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Do you have access to a sound-meter? (i don't know the word in english for this, the readings you could get are in decibels of SPL) It measures from each source, you could sit in the center of the 5.1 if that's the application or in the center of the stereo and measure each channel SLP separately, this way you will now if they match and if they differ, by how much decibels, and it takes into consideration not only raw power but efficiency of the speakers, layout, cabinet,etc, It should be done not with tones but with pink-noise. If you happen to like Pink floyd music, the pulse DVD has a nicely done tool to set up a 5.1 with the "sono-meter" using pink noise, but you can get those sources from any analyzer program such as RTA.
regards.
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Old 24th March 2012, 04:54 PM   #6
panduro is offline panduro  Denmark
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application, it for bi/tri amped speakers for homecinema, xover is dbx pa+.

im having a real hard time getting the exact same sound level out from the midrange drivers(same drivers, same enclosures, same stuffing) in the right and left speaker when they are fed by 2 different channels in the power amplifier.
They simply dont play the same volume when i have tried to adjust the level controls by using pink/white noise and a spl meter.
The dbx is set to the same gain for both drivers and they get identical signals.
so i think i have too measure the output voltage in the poweramp to be able too set the those level controls in the power amp precisely.

Did that clarify my problem?

Last edited by panduro; 24th March 2012 at 04:57 PM.
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Old 24th March 2012, 05:02 PM   #7
panduro is offline panduro  Denmark
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Yes i have tried a spl meter, but it seems that the level of pink/white noise isn't completely flat, it rises and falls.

tried with two different meters, low budget radioshack and a better digital vellemann spl meter. same result.
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Old 24th March 2012, 05:08 PM   #8
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There are members here more qualified than me in order to measure the output power/peaks. You could go with an oscilloscope and measure the Vout with a tone as input, using same signal source, with real speakers as loads I've always had a hard time with triggering the signal in my old analog oscilloscope, you can try dummy loads instead for a preliminary observation and then go on with the speakers.
Dummy question.. I assume you swapped the speakers and the problem was still there..just asking. I do hope some members can give you a more accurate solution.
regards.
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Old 24th March 2012, 05:32 PM   #9
panduro is offline panduro  Denmark
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jep has tried to change speakers.

**** was hoping for something i could do with a volt meter
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Old 24th March 2012, 05:43 PM   #10
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There's a thread around here talking about setting the voltmeter in AC and it will give a comparative reading between the differences of volume. I mean use a tone, and use the volt meter in the AC scale at the output amplifier. Try searching for this thread. It sounded good to me, but i can't remember the frequency of the tone-signal, which I think is critical.

I hope this helps.
regards.
Out of curiosity, your nickname means "hardbread" in spanish, even families here are called by that nickname. Does it have another significance?
regards.
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