They're second hand so plenty of break in...
Tried a little more tweaking today, still no stands but managed to set them further apart and I also toed them in a little. The result is better, and they definitely sound much better with the volume turned way up (not surprising). I highly doubt that they're faulty but it still worries me because I find it hard to believe that all of the reviewers and owners heard something similar to what I'm getting and thought it was the best thing since sliced bread.
Maybe my living room is really that bad... I just expected them to be crisper and shinier, if that makes any sense. The sound is decent, but not what I'd call audiophile.