Serious Question Regarding USB Mics....

[Foggy]

"back up from the mic"
MorningStar is likely too be trying to help you minimise proximity effect of your cardoid mic .
The proximity effect increases the lower frequencies when the sound source is closer , this could be what you are describing as "muddy" sounding or dull (as well as effective pop filtering) .

Although I would say usb mics are crap .

[CPhoenix]

I'm not familiar w/ USB mics. Does their built-in preamp have a gain on them? If so, step back and maybe try adjusting the gain.