In reply to:

why would it only sound muffled during the test tones every time and in different channels and locations?


Because the room and speaker placement strongly affects the sound as well. It's not often noticeable with the complexities of music as a sound source, but very often IS noticeable with test tones.

I'm not saying if you do or don't still have a problem, I just wanted to answer that particular question for you!

::::::: No disrespect to Axiom, but my favorite woofer is my yellow lab :::::::