Subwoofer works on blu-ray but not on TV?

My system:  McIntosh MX-121, MC8207 amp. Denon DBT-3313UDCI, and an SVS subwoofer model SB-2000.  The sub works fine when using it to watch movies on the Denon.  It does not trigger on while watching the TV.  The rca cable is plugged into the SW1 on the processor.  Do I have something set wrong on the processor?  The sub is set to LFE as directed by SVS directions for use with a processor.  The switch on the sub is set to standby, with no 12 volt trigger wire hooked up.  Any suggestions would be appreciated, thanks.
How have you set up bass management for each input?

What is your TV, satellite, cable, or OTA? What are the connections to the TV and to the MX-121?

Kr4  I bet you are right about the bass management not being set up.  I'll have to get the msnusl out and look into this.  Thanks a lot.