If you select the DVD input, and select optical inputs opposed to the 7.1 inputs you can select stereo as a surround mode. This mode appears to put a very weak base signal to the sub. If you press the bypass button it has no effect. If you select the 7.1 DVD input mode and your bass management is set "bypass" then your surround setting simply says "bypass" and you can't change it to anything else. If you select the 7.1 DVD input mode and base managment is set to digital, your surround options are limited to digital, dolby +PCM PL11x-C and M.