The only difference between 3.10 and 3.11 is a fix for the subwoofer trim (3.10 has a bug that shows up when you set it to -15dB, causing it to effectively disable the sub trim and act just like a 0dB setting).

One thing to try to verify that you are getting proper sub response would be a frequency sweep like that included on Digital Video Essentials (or like my Devious Tiny Disc . There have been cases where people were used to exaggerated bass and were befuddled by the results initially achieved by a flat response. This can also be helpful for getting subwoofer phase checked out, as Jeff mentions.

As for the second problem, something certainly sounds "off." Does the tinny sound show up with all of the sources, or one in particular? It sounds like it is global. Have you double-checked all of the connections? I've had sonic problems before that were the result of a loose cable, which would certainly mess things up across the board.