Well the IE800 is a smooth sounding enough IEM already in my book, it's neither hot nor fatiguing to listen, even loud, due to a rather massive dip at 7/8khz, treble is not just only the 10khz band. After being quite impressed by it initially, I have come to rather dislike the kind of "refined" sawtooth shaped treble the IE800 and many others do and when I want bright I much prefer IEMs with more linear treble such as the Panasonic RP-HDE10 I currently have in my sig. I didn't say that treble should be rolled off in every IEM or that people shouldn't have choices... I just said that the IE800 isolated and exaggeratedly high top end could be considered a weakness by some just as other consider it a strength. And cymbals certainly don't sound like they sound live with the IE800 IMHO. As for why it sells so much, it's open to debate whether its qualities alone account for it. Senn's brand name along with their massive distribution network and advertising might account for quite a good portion of that.