Every gym I've ever belonged to plays music over the speaker system, and the one I'm a member of now is no exception. I listen to audiobooks while working out (I've given up listening to music, because it can't compete volume-wise with the music over the speakers ), and I want some earbuds that let me do this with without having to crank the volume up to a dangerous level. I've already got a high-frequency loss in my left ear (I wear a hearing aid there most of the time because of this, but not at the gym), and I used to work as a professional musician, so I'm very aware of protecting myself from more damage/tinnitus. I'm looking at the Etymotic Research MC5 Noise Isolating In-Ear Earphones right now. Anyone have any experience with the sound-isolating aspect of these? The reviews seem good... Thanks!