Ideas for Quad VCA project

[PRR]

> David Gilmour's guitar solo on a Pink Floyd tour (I forget which one) was run through a quad panner so that his guitar was coming from all corners of the venue in sequence.

He had cash.

About the same time I did the same for a theater production. Four LDRs in a hatbox (probably a cookie-tin). Lamp in center, crank on a can with a hole in the side. Adjusting LDR and hole size/location gave a fair constant-insanity pan-law. (Obviously the operator did not have two hands on a guitar. One on the main sound mixer, one on the pan-can.)

[Scruffie]

I've been experimenting with this, but found it a bit noisy. That's just the curse of OTAs, I suppose. You don't notice using the chip as a lowpass/highpass/bandpass filter because so much signal is removed, there's not much noise left either. As soon as you turn it into just a narrow notch that is removed, you can hear gently phased hiss while you're not playing. Still, there might be a way. Or stick a compander on it, like you suggested.

I came to the same conclusion, I even did one with emphasis and companding and for half the sweep it was fine (although still not the quietest) but once it got to the top part of the sweep it was more noisy than a BBD chorus... adding some low pass filtering helped a bit but at that point I decided 10,000:1 for guitar was just overkill and the benefits of 4 stages on a chip had quickly evaporated.

[StephenGiles]

I've been experimenting with this, but found it a bit noisy. That's just the curse of OTAs, I suppose. You don't notice using the chip as a lowpass/highpass/bandpass filter because so much signal is removed, there's not much noise left either. As soon as you turn it into just a narrow notch that is removed, you can hear gently phased hiss while you're not playing. Still, there might be a way. Or stick a compander on it, like you suggested.

I came to the same conclusion, I even did one with emphasis and companding and for half the sweep it was fine (although still not the quietest) but once it got to the top part of the sweep it was more noisy than a BBD chorus... adding some low pass filtering helped a bit but at that point I decided 10,000:1 for guitar was just overkill and the benefits of 4 stages on a chip had quickly evaporated.

I wonder why the 2064 was Ashdown's IC of choice, I haven't heard any of their pedals though.

[Mark Hammer]

How about a quadraphonic panner?

I've been thinking of whipping up just this. Many older home theater amps had analog inputs for 5.1 audio. David Gilmour's guitar solo on a Pink Floyd tour (I forget which one) was run through a quad panner so that his guitar was coming from all corners of the venue in sequence.

Trust the Floyd to go for a quadraphonic system at a gig!

It shouldn't be too difficult. The potential issues I foresee are designing and building an oscillator that can produce four outputs 90 degrees out of phase, and designing a equal-power panner so that the perceived volume of the signal doesn't dip (or peak) as it travels from one speaker to another. Given that the 2164 has a log control law, I need to think about the maths of that, and I can't do that without the back of a *large* envelope and a pencil!
Neither problem is insurmountable, or un-previously-solved.

Some 45 years ago, I attended a concert that aimed for a hexaphonic distribution in low-tech fashion.  It was a contemporary music concert, featuring a piece by former-architect-turned-composer Iannis Xannakis.  The audience was invited to all congregate on the main floor of the concert hall (some had been seated in the balcony), and musician "stations" were situated in a circle around the audience, at 60 degree intervals.  It was a percussion piece (including pitched instruments, like marimba), and the score was written such that instruments of equal "density" and loudness were played by those 180 degrees apart.  As the musicians would rapidly switch between percussion instruments, the music would appear to revolve around us, like a propeller.  A pretty special and memorable experience, I have to say.

[Kevin Mitchell]

I've been thinking of whipping up just this. Many older home theater amps had analog inputs for 5.1 audio. David Gilmour's guitar solo on a Pink Floyd tour (I forget which one) was run through a quad panner so that his guitar was coming from all corners of the venue in sequence.

Are you sure you're not thinking of his Shine On You Crazy Diamond acoustic show? He used an Ernie Ball stereo panner. One side was clean and the other was a quick delay with a ton of repeats. He would strum a chord clean, pan into the delay channel, pan back and solo over the fading delay.

That's what came to mind reading your post 

[rockola]

I've been thinking of whipping up just this. Many older home theater amps had analog inputs for 5.1 audio. David Gilmour's guitar solo on a Pink Floyd tour (I forget which one) was run through a quad panner so that his guitar was coming from all corners of the venue in sequence.

Are you sure you're not thinking of his Shine On You Crazy Diamond acoustic show?

I must have been thinking of the https://en.wikipedia.org/wiki/Azimuth_Co-ordinator