How grills affect?

From the Thiel 1.5 manual:

"The grille on the CS1.5 is designed as an integral part of the system to reduce unwanted diffraction effects. Therefore, it must remain in place for proper operation. If you do need to remove the grille, pull the bottom of the grille frame away from the speaker an inch or so and then pull the top of the grille forward to remove it."

I have no speaker design knowledge but clearly Jim Thiel sees reason for the grilles. Not sure what that means though.

I like the way JM Lab Utopia series does it. the "speaker grilles" are actually solid wood "speaker protectors." They are to be put in place so that the maid can come through the room and clean things up without damaging the speakers. Of course, this would work well for women and children also. So, obviously, with these speakers you would remove the grilles for listening.

Thanks for the great thoght sharing. I do understand that sometimes I'd take them off but UNfortunately my kid taps the drivers only during listening. He doesn't care about the drivers or speakers any other time!

The Thiel CS1.5 grille is unique in that it actually has a sizeable rounded wood frame which gives the front of the speaker ALL of its anti-diffraction properties. In other words, without the grilles in place, the front of the speaker has no rounded corners at all. The Thiel CS2.3s are not like this and I'm sure that very few speaker grilles are designed this way. I never thought about it but the CS1.5 would be a good speaker to experiment with to see if the rounded shape actually makes an audible difference. I have my CS1.5s set up as my main speakers right now so I will try to do this experiment and post some results in the next day or two.

I have the Dunlavy SC-V (s) and there is no question that the speakers sound more definitive with the grills off.