On 16/02/2020 12:19, Augustine Leudar wrote:
I'm mainly interested in purely analog devices in this thread
The small team I was involved in during the 1970s built a 4-input proof-of-concept Ambisonic mixer. We were interested in developing a mixer to produce B-format from multitrack recordings, creating an artificial soundfield.
It had 360-degree panning ability and radius-vector control on each. Two input channels used sine-cosine 360 degree potentiometers derived from scrapped electronics, probably radar consoles. Because we were unfunded and basically running on 'pocket money', the budget didn't allow for 4 sine-cosine pots so we designed and built two switchable pan-pots, initially 30-degree but planned for an eventual 15 degrees.
Switchable pan-pots consisted of an array of wafer switches with hordes of 1% metal-film resistors. Not a build for the faint-hearted, and probably not even attempted had we not made use of an early programmable calculator!. 15-degree switches were under construction at the time the whole project was abandoned. The chassis of the mixer still lies somewhere in a heap of discarded electronics at the end of my garage!
Despite its Heath-Robinson (or even Rowland Emett) appearance the mixer did work and produced very interesting results.
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