grills on or off on evolution acoustic speakers?

Either way is fine - as far as I can tell from photos it will not matter - whatever looks nicest.

Mike (Audiohifila) I'm not surprised that performance was better with grills off. You can ask this question to Mike Lavigne or Jonathan Tinn as they both use the MM3 as their reference speaker.

My guess is they hear the same thing you do. I heard Mikes system this last week, excellent speakers those MM3.

Mike, I prefer to listen to my MMTwos with all the grills removed. I agree with you about the sound of the bass. When the bass grills are removed, I have found there is significantly greater clarity and cohesiveness where the upper midbass blends with the sound of the midrange drivers.

Like almost all speakers, my MM2's sound best with the grills removed (more open and transparent). I simply remove the grills prior to listening. I always keep the grills off the ceramic mids since they are protected with their integrated grill.