There's a stereo button on the remote. You can connect through an optical cable and select the stereo mode. Set your speakers to small and the crossover will direct the low frequencies to your sub.
_________________________
Main HT <> 976 <> 7200 <> Ultra-X12 <> sapphire ST2 mkII RF/LF <> sapphire SC center
sapphire ST2 mkII SBR/SBL <> sapphire SS SR/SL <> Verizon/DVR <> Vizio M70Q7 <> Oppo UDP-203 <> Amazon 4k Fire TV