Im just wondering, about the one ear deaf people. Im very sorry but I just do not at all believe that they do hear more or better with the ADEL, not because of its frequency response (which is focused on the sensitive part of the human ear) but because of the pressure-relieving membrane. Why would anybody deaf not hear the same with a good headphone? Most of the time because they isolate less, they have to be set at a higher volume than in-ears, resulting in *more music traveling from the one side of the ear to the OTHER cochlea* by their logic. Also headphones (even closed!) need a bit higher SPL (sound PRESSURE) level to get the same perceived volume, which means only more pressure in the ear!! How problematic, fortunately only IEMs have that problem. It seems. I wonder if making a small hole in any in-ear/closed headphone will *do the same* as adels idea. Only having less isolation, a very very tiny bit less (dont tell me a small membrane does isolate more than no membrane).