It could be the receiver I have, it's a Technics sa 6700X which has a width and depth adjustment on the decoder. I was running the demodulator through the discrete mode however, which has two different settings, one with AFD on and one with AFD off. The matrix decoder has two settings also, 0 degrees and 90 degrees, and the decoder circuit is controlled by two sliders marked width and depth referred to as Acoustic Field Dimension. A brochure I have says about it: " By incorporating two continuously variable controls, one for width coefficient and one for depth, Technics AFD ( Acoustic Field Dimension ) Control System makes possible precise adjustment to any matrix system in use today, as well as any that may possibly be devised in the future". Now I was running the discrete mode with the AFD off, but perhaps this amp applies some decoding to the CD-4. When playing Quadradiscs I get very sharp separation. But I definately was hearing 4 channel information through the demodualtor from both the SQ version of AHM as well as DSOTM. I even put on a mono copy of Jefferson Airplane "Bathing at Baxters" and it separated it into 4 channels, and the Tate doesn't even do that, it gives me a mono mix coming primarily from the front channels. I suspect the decoder scheme in this amp is similar to the Audionics Space and Image composer. This amp also allows you to run the demodulator and set it to the matrix position, and you get a smoothed out 4 channel mix from a Quadradisc. Since the receiver has three 4 channel tape monitors, it runs the information from the rear channels of the demodulator through the decoder.