Of course it should be mentioned that most grills are *extremely* transparent to the sound, so what doesn't make sense is that having no grills would subjectively make so much difference in the sound. But nobody ever experiments to see why a transparent grill is so bad for the sound. You could even make an experiment using a grill that has only say 1/5 of the number of strands of fibers so the grill is mostly open. Then it would be really, really difficult to explain, no? Same goes for headphone grills, they are bad news.
