My question was ineptly asked. Did PMC design their speakers to sound "best" with the grills on or off? I.E...are the grills intended (by PMC) to play a role in sound production in any way?
FWIW, I too leave the grills off unless "Arthur", my 3 year old buddy of the many sommersualts and accidental cartwheels in the living room is coming to visit, when then I nervously replace the grills.