Any Harbeth that I've owned are made to be used with the grilles intact. This is stated by the designer Alan Shaw. It is very difficult to remove the grilles without using the special tool used for removal. Anytime I see used Harbeths for sale they almost always have a rip on the corner of the grille from careless removal!
Anyone Using Harbeths with Grilles off?
Curious whether anyone prefers their Harbeths this way. I would imagine it's room dependent-- they are obviously voiced with grilles on but if your room is unusual (like mine is) maybe they sound better this way. The highs are getting eaten up by furniture and old ears and a strange loft type room at my place so it's working here.