I'm sure it's been said but I'm thousands of posts behind so I'm admittedly skimming but make sure you try it with all of the receivers EQ or other effect choices turned off. One of my most scary experiences was when I somehow turned on the EQ feature and it became set to Flat. Hollow would have been a very good word to describe the sound but for me it was an overall hollowness, not just one speaker but I use that as an example.

With great power comes Awesome irresponsibility.