Grilles or No Grilles

I think you cannot generalize.

If the speaker was designed and voiced with the grille cloth on, then it will only be able to perform as intended with the grille cloth on.

If the speaker was designed and voiced with the grille cloth off, then it will only be able to perform as intended with the grille cloth off.

Someone's personal preference is simply a personal preference.

Kal

In my experience too - no grilles is always better.

I wish I could say my speakers sound better with the grills on, because they look better that way. But they sound more veiled, which makes sense. As a matter of fact, I'm sure vast majority of the speakers aren't meant to have grills on, it's just that some people might like the way it looks or maybe also to protect the drivers better. I guess though, if the speaker is too aggressive, the grill could tame the sound a bit, which might help.

And equally valid is the psychological effect of removing the grilles and believing, therefore, that the sound was more direct. There's little doubt that the grilles change the sound but it is not universally true that the change is an improvement. See JA's measurements and comments here: http://www.stereophile.com/content/paradigm-reference-studio60-v3-loudspeaker-measurements

Kal