Doc, you can of course get a reasonably accurate idea if you're in a danger zone on sound level by positioning an SPL meter about a half inch from the pad while playing the material at the volume setting in question.
Since Grado supplies the flat pads with the 60/80/125, it would seem that the driver is designed to work best with the attenuation of the pad material over it taken into account. If the "bowl" or "doughnut" pad is used instead, presumably the upper frequencies will become more prominent(good or bad) because of the lack of attenuation without the intervening pad material.
