Is that the input signal or what the 975 is putting out? Even if the input signal is two channel the 975 can turn it into 5.1 using Dolby processing. It could be 5.1 coming in as many station are broadcasting that signal.
Model 990/7500/Magnepan 1.6 QRs/Technics SL1200 MK2/Aperion S-12 Subwoofer/OWA3/Sony NS75H DVD
Large Advent Loudspeakers/Panasonic Viera 42 inch/Onkyo HT-RC260/Sony BDP S590
Home Theater System
Onkyo PR-SC886/7125/Klipsch RF-82 L/R,RC-62 center, RB-35 SR/SL, BENQ HT1075, Outlaw LFM1-EX/OPPO BDP-83/Directv
Blue Jeans and Monoprice interconnects
APC H15 Power Conditioners