No bass coming out of the subwoofer

Ensure that the HTR9900 subwoofer is connected to the household power supply.

There is a power ON switch at the back of the subwoofer. Push it to the 'ON' position. You should be able to see a green LED light on top of the switch. This means that the subwoofer is powered on. In the setup menu, you need to toggle the SUBWOOFER to 'ON' under the SPEAKER CONFIGURATION Option. Adjust the bass levels in the receiver unit setup menu and turn the OUTPUT LEVEL knob at the back of the subwoofer to get the desired bass level.

For other brands of subwoofer, there may be other ways to get the bass from them. Please contact the subwoofer manufacturer for more details.