Hi GettingOld! The subwoofer is responsible for low frequency sounds, like the rumbles of an explosion in an action movie or the bass guitar and drum in your favorite music. It adds rich bass tones and deepens the sound quality you hear, but since the subwoofer only plays low tones, it will be silent when low frequency sounds are not in use. If you'd like louder (or softer) bass from your subwoofer, you can adjust the level by toggling the WOOFER button on the soundbar remote, and then adjusting the level from -6 to +6. To set the subwoofer volume level to 0, press the button down.
I am very sorry that you are not happy with the volume of your soundbar. Simply changing the Digital Output Audio Format to PCM can help. You may want to try changing the Digital Output Audio Format to PCM.
This can be found at Home > Settings > Sound > Expert Settings. (It can also be found in the Quick Settings.)
If your Digital Output Audio Format isn't set to PCM, like for instance if you have a Dolby option selected, then you will likely notice decreased maximum volume. Dolby options are designed for surround systems (like 5.1 or 7.1), whereas PCM provides great sound quality for stereo speakers.
If you don't have a surround system, you will probably want to select PCM. You'll get much louder volume that way, and potentially better sound quality. ^Patty