A Discussion About True Power Summing for Stereo Compressors

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mediatechnology
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Re: A Discussion About True Power Summing for Stereo Compressors

Post by mediatechnology »

Using the DI path to key the acoustic is a neat trick.
emrr
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Re: A Discussion About True Power Summing for Stereo Compressors

Post by emrr »

The only comp I can think of offhand with a weighting control is the Manley/Langevin ELOP.
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Doug Williams
Electromagnetic Radiation Recorders
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mediatechnology
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Re: A Discussion About True Power Summing for Stereo Compressors

Post by mediatechnology »

I think I figured out a simple way to do this.
Put two 10KΩ linear pots ahead of the RMS detector inputs to control detector level.

Hook the pots up in a potentiometric (3 wire) connection so one is reversed to the other.

The wipers go to the coupling caps in series with the RMS input.
The hot side of the pots connect to the input diff amplifier at the original RMS detector sampling point.
The third terminal of the pots are grounded.
Decrease the detector input resistors by 1/2.

The pot then becomes a detector weighting control with the center position being both RMS detectors at 100%.
Panned hard to one side one channel is at 200% and the other at -∞ weighting.

Whatever you do make sure that there's no DC path to ground at the RMS detector input pin.
The bias current from the RMS detector's input op amp should have no DC path to ground.
Bias current is supplied by the feedback path.
If a bias current flows out the input the DC that develops will upset low-level RMS measurement.
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Re: A Discussion About True Power Summing for Stereo Compressors

Post by emrr »

Dual single shaft pot I assume, has to be.
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Doug Williams
Electromagnetic Radiation Recorders
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mediatechnology
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Re: A Discussion About True Power Summing for Stereo Compressors

Post by mediatechnology »

Yes, a single-shaft dual.
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Re: A Discussion About True Power Summing for Stereo Compressors

Post by emrr »

Thanks, will report back once tested.
Best,

Doug Williams
Electromagnetic Radiation Recorders
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