This is a common problem with subs. Try turning up the volume on your receiver or turn the switch on the sub to "on" and then back to auto mode.
My SVS subwoofer will not turn on from auto mode
I have a small(9 by 10) room and installed a new SVS SB 12 subwoofer into a 7.1 system.Problem is my Yamaha receiver does not seem to wake up my sub from auto mode.Since room is small and in a 2nd floor condo I cant run the sub very loud so gain is in 10 o'clock position. SVS said I should keep sub gain at 1 o'clock position but that is too loud for my condo.Any trick to getting the sub to turn on from auto mode without loud volume setting?