For me it was off until I stopped my daughter's 8 year old friend 1 second before she put a finger through a tweeter... Now it is definitely on
Grills are always off my Neats. I found that clarity takes a hit with the grills on.
Time ago I had to install a kit for a party in the office and when I was loading in the car a pair of speakers I had stored for a while I realized they were broken.
Beeing in a hurry to solve the problem I bought a pair of q300 Kef's after a very short audition of thr demo pair in the store.
In the office I asked someone to install the speakers to the amp and launch a playlist. The speakers sounded very dull ... but the party was very nice.
After the party when I was putting the speakers back in the boxes I looked at the back of the speakers and read "Made in China", ahah, that was it! I thought, but in the store they didn't sound so bad, ahah, burn in! I did that at home but almost no improvement. Back in the boxes. A year later I had another need for speakers and there where the KEFs. When I was installing them I put off one of the grilles and to my surprise a piece of a sort of foam was in between the grill and the woofer/twitter to protect them. @#$% No comments please just insults.
Grilles could be on or off depending on the speakers and taste of the listener, but please, protection material, being it foam, non woven fabric or the like, OFF!
On please. But with most modern speakers, you don't even get to choose.