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Dynaco's QD-1 Quadaptor - an early attempt at surround sound .. photos .. on Sun Nov 01, 2009 1:32 pm
Bob Latino
Admin
The Dynaco QD-1 Quadaptor, which was released by Dynaco in 1971, was an early attempt at "surround sound". It was developed at Dynaco by David Hafler and Sid Lidz. It was a passive (no power supply, no gain etc.) unit that you put between the stereo outputs of your power amp and your speakers. You added two extra speakers, one for the left rear and one for the right rear in addition to your two regular (front) left and right speakers. The QD1 extracted some of the ambient sound information hidden in the sum and difference signals present in the two stereo channels and sent this ambient sound information to the two extra (rear) speakers. It had a rear level control and a 4 way balance lever that allowed you to control the left/right and front/back balance by simple moving the lever to the correct position that provided the best surround image in your listening position. Below are two photos of the QD-1, the QD-1 schematic and the Quadaptor page from Dynaco's 1975 product brochure.
Bob
Bob
