Check the power switches on the back of the subwoofer. Make sure the PWR ON MODE switch is in the AUTO position and the MASTER POWER switch is turned on.
Press the MUTE button on the remote control to make sure the sound wasn’t muted or turned off.
Unplug any headphones that may be plugged into the AV controller.
Try increasing the volume. Depending on your audio source, it’s possible that no sound may be heard at the low end of the +dB range.
If you’ve connected an external audio device such as an MP3 player, make sure its volume control is adjusted to allow sound output.
If you’ve connected an external audio device such as an MP3 player or tape deck, be sure to select the correct audio port: Select the AUDIO option on the remote control, then select either AUD1 (for the AUDIO 1 port in back of the AV controller) or AUD2 (for the AUDIO 2 port in front).
If you’ve connected an external component, check the Source Assign screen. Make sure the selected Audio Input matches the port to which the audio is connected. See Linking Audio and Video Sources.
If you’ve connected an external video component using an HDMI cable, make sure HDMI audio is enabled in the component’s setup menu. If your component doesn’t support HDMI audio, you may need to connect a coaxial or optical cable to carry the audio signal. See Connecting the Audio Cable for the Video Source.
Check for loose or disconnected cables on the back of the subwoofer and AV controller