Yes, I did it to a B&W HTM61 nearly brand new so that it would match my other black speakers:
One of the speakers I was matching:
I used Krylon Plastic Paint. I believe it was matte finish. I was actually shocked at how perfect of a match it was to B&W's black ash. Only prep I did was tape off any areas I didn't want painted. I've painted monitors, Xbox's, etc.. this way.