Think, if you're getting the sub's level test tone, I think you need to fiddle with the bass management settings. It sounds like the sub (LFE) track is being redirected to your main speakers, especially if you're hearing the test 'rumble' with your sub turned off.

In reference to your top post, you might try BOOSTING the other channel levels to bring them closer to the bass level. Remember, there are no 'absolutes' when using decibels for level matching, only 'relatives'.

Larry