I added in a x-fi fatal1ty card myself and bought and hooked-up a set of z5500's to my system. For a while (2 days), everything was going great.
However, as anyone who owns anx-fi knows, there are a ton of software features that allow you to mess around with your sound.
Well, mess around I did. I didn't think I was doing anything too serious. However, after I have set everything back to where I thought they were before (restoring defults and restoring my minor adjustments to when the sound was satisfying), my music still sounds washy and unsatisfying.
Moreover, when I run the speaker diagnositcs, only 2 of my 5 speakers "report": the front left and rear right. Before, it was only my front right that missed out, but because everything sounded great, I didn't bother trying to figure it out.
As it's obvious that there's something wrong with the setting, I would recommend to uninstall all the apps and drivers that came with the card and the reinstall. It could save you hours of trying to see where it all went wrong.