Wayne Parham Messages: 18789 Registered: January 2001
Illuminati (33rd Degree)
Speaker grilles are sometimes a "necessary evil." They do create a little bit of self-interference because they aren't perfectly transparent, acoustically. But they are close enough to the source that the self-interference isn't too bad, almost nothing at low and midrange frequencies.
So absolutely, if you need a grille, add one. I like attaching them in such a way that I can take them off, when they aren't needed.