Now normally i refuse to have the going on in QQ mentioned here but i’ve been sent the details of a post there thatdoes so annoy me. As many will know, one of my gripes about QQ is the total lack of real knowledge about the subject that they profess to know about. One of the areas where they completely fail is in the area of the early pre- phas-shifting matrix systems DY & EV-4.
As i’m sure your all aware of, AOQ is running a ‘shoot-out’ on this very subject and i feel this new posting not only blurs his attempts.. Here’s what i’ve been sent:
“Are EV-4 and QS compatible with each other? Decide for yourself. EV-4 encoding uses a front blending coefficient of 0.2, slightly less than QS at 0.414. The back channels use a blend coefficient of 0.5 compared to QS at 0.414, slightly more. The decoded result will shift the fronts a bit toward the sides and the rears a bit closer together. Overall the decode should still be quite good.
The only other difference is that QS encoding phase shifts the rears by +90 degrees (left) and -90 degrees (right) to create a 180 degree (out of phase) difference. This phase difference is done directly with EV-4. This rear phase shift is reversed by the QS decoder. Ideally the rear phase shift should be switched out for EV-4 decoding and for stereo enhancement and switched in for QS. I believe that Sansui decoders leave the phase in shift both for simplicity and to increase the apparent separation of the rear decoded outputs for stereo enhancement (as they always referred to their units as “SYNTHESIZERS”).
I would think that one could tweak the separation pots in a QSD-1 or QSD-2 to perfectly decode EV-4. At some point I might try bypassing the phase shift in my unit to see if I hear a difference, positive or negative on none QS encoded material.
Forget about “correct” EV-4 decoding, those units were designed more stereo enhancement, basically an active version of the Dyna-Quad speaker connection. The asymmetrical decode was the best that could be done without using any form of logic.”
Now, if someone who has access to QQ and is willing to reply to this for me, i’d be grateful. My reply is: