Search found 660 matches

by Gold
Thu Jan 15, 2009 7:47 pm
Forum: Pro Audio Design
Topic: Mid Side M-S Matrix Uses No Precision Resistors
Replies: 264
Views: 496694

Re: Mid Side M-S Matrix Uses No Precision Resistors

Great news. I'm in for eight.
by Gold
Tue Dec 09, 2008 10:33 pm
Forum: Pro Audio Design
Topic: OTB Mixer Using Current Summation
Replies: 137
Views: 184930

Re: Pease - What's All This Adjustable Slew Rate Stuff Anyhow?

JR. wrote: My point is that I will not waste any more time trying to perfect a circuit that can't be perfected,
That was my point too!
by Gold
Tue Dec 09, 2008 7:12 pm
Forum: Pro Audio Design
Topic: OTB Mixer Using Current Summation
Replies: 137
Views: 184930

Re: Pease - What's All This Adjustable Slew Rate Stuff Anyhow?

I think the only useful metric of pan law is spl, and that is a moving target. Hence the fudge. I have a feeling I don't quite get your point though.
by Gold
Tue Dec 09, 2008 4:30 pm
Forum: Pro Audio Design
Topic: OTB Mixer Using Current Summation
Replies: 137
Views: 184930

Re: Pease - What's All This Adjustable Slew Rate Stuff Anyhow?

I have come to the conclusion there is no arguably "correct" pan law. The constant power law (which they don't really follow) doesn't hold water for coherent sources, since the power is not in fact constant when SPL or voltages are recombined, while I prefer the feel of -3dB law, versus -6dB which ...
by Gold
Tue Dec 02, 2008 3:03 pm
Forum: Pro Audio Design
Topic: Mid Side M-S Matrix Uses No Precision Resistors
Replies: 264
Views: 496694

Re: Mid Side M-S Matrix Uses No Precision Resistors

Thanks Wayne. I'm glad best performance is the goal.
by Gold
Mon Dec 01, 2008 11:57 pm
Forum: Pro Audio Design
Topic: Mid Side M-S Matrix Uses No Precision Resistors
Replies: 264
Views: 496694

Re: Mid Side M-S Matrix Uses No Precision Resistors

mediatechnology wrote: Because it's non-inverting, the CM performance of that stage requires careful op-amp selection.
Although it's OT could you give a little lesson on why this is important and what about the 797 makes it a contender?
by Gold
Mon Dec 01, 2008 7:49 pm
Forum: Pro Audio Design
Topic: Mid Side M-S Matrix Uses No Precision Resistors
Replies: 264
Views: 496694

Re: Mid Side M-S Matrix Uses No Precision Resistors

In the above drawing it's not clear whether the AD797 is inverting or non-inverting. If inverting there should be another inverting opamp before the pot or some way to flip the polarity so absolute phase is maintained. It would take a 3 pole switch to flip the input to the 1240 along with the variab...
by Gold
Sun Nov 30, 2008 3:09 pm
Forum: Pro Audio Design
Topic: Mid Side M-S Matrix Uses No Precision Resistors
Replies: 264
Views: 496694

Re: Mid Side M-S Matrix Uses No Precision Resistors

Looking at Wayne's gain trim circuit above the only downside I see is that the mono sum will be between 3dB and 6dB up already. Having 3dB of gain at the input might have headroom issues. It seems that to "fix" this you would give up the precise level matching by having makeup gain set by external r...
by Gold
Sun Nov 30, 2008 2:17 pm
Forum: Pro Audio Design
Topic: Mid Side M-S Matrix Uses No Precision Resistors
Replies: 264
Views: 496694

Re: Mid Side M-S Matrix Uses No Precision Resistors

Paul/Ruairi - If the +/- 3dB trim were on a pot would it be precise enough from a repeatability perspective? If not, one could build it as a stepped switch. It sounds like to me that you are leaning towards switches. Maybe we should make the board accept both types of controls. I think +/- 3dB on a...
by Gold
Sun Nov 30, 2008 10:03 am
Forum: Pro Audio Design
Topic: Mid Side M-S Matrix Uses No Precision Resistors
Replies: 264
Views: 496694

Re: Mid Side M-S Matrix Uses No Precision Resistors

Thanks for the input everyone. Another option is, of course, a knob with a pushbutton to switch between "fixed" and variable. With only +/- 3dB range the knob would have fair repeatability (and less chunkiness compared to a switch) based on pointer position. The switch or relay would only need to b...