Pro Audio Design Forum

Aren't we saying the same thing? Not exactly, John but close. Summing after detection, at least with rms, washes out coherence/incoherence altogether. It doesn't emphasize or de-emphasize those components. They just don't matter. I think I would agree to: "That said using "RMS" detec...

That said using "RMS" detection (or IMO any rectification) before summing, will over report incoherent signals relative to coherent. Thanks for the discussion John. I agree with most everything else except the above. I believe the opposite of the above is true: Summing prior to rectificat...

Just found this interesting dbx article:

ftp://ftp.dbxpro.com/pub/PDFs/WhitePape ... icsDuo.pdf

I think you would still want it the same. I haven't really followed that thread.

Yes, like that. You could also move R2 over to the other side of the switch right by R1. That way, through the other path, the OPA604 isn't loaded by it. The reason why I think it may be better (using 1k+(1.2k||fader)) than a lone 10K is that at the top of the fader travel the source impedance will ...

Another thing you might try is a 1k buildout from the 1240 output. Then add ~1.1 - 1.2k across the 10k pot to make that leg 1k. That gives you a 2K Rt divider with 6 dB attenuation and a 500 Ohm source impedance at the top of the pot. This might be a better solution than the one I originally suggest...

Looks like you could insert a series resistor between the M-S out and the pot. Use the pot as the lower leg. You would have to hand-pick the value though since the pot won't exactly be 10K. ~10K would get you 6 dB though. Tolerance outside the matrix (post-decode in this case) only affects channel b...

radiance - Thank you for checking in with us. You are correct that the decode section will need a 6 dB pad on the output to eliminate the 6 boost. 1246s cannot be used there because summation to derive the left output cannot be performed using both the +input (pin 3) and the ref pin (pin 1). The res...

Forgot to mention that I have a pair of 2162 demo boards. Each demo board represents a channel. With those two boards I can make a 2 input mixer as a current summation test bed.

I think that may be my gig once I clear off the bench.

Wayne