How grills affect?

I leave the grills on. Softens the highs just a hint. It is enough to reduce listener fatigue on less then ideal recordings and that occasional digital edginess.

In regards to Garfish's comment: yes, check the manual for the specific speakers. Someone with a pair of B&W Nautilus series; comfirm that B&W actually recommends removing the grills for serious listening. I can swear I read that when I was reviewing the manual at a dealer. I use to own a pair of the Matrix series, and those grills were designed to disperse the sound a certain way, so for the Matrix, they should be left on.

Well, this post got me into playing around with the grills on my speakers again. I still like what I hear better with them on. I suppose like everything, it depends on many factors, not just the speakers. I am now playing around with the grills on my speakers in my home office room while I'm here at the computer.