I won't be handling in-ear monitors (IEM's) since my partners, RK Audiology do a fine job with those, but these are awesome products. I personally use Westone 4's with custom-molded earplugs and an ancient pair of Etymotic 4s. I will probably get into a pair of fully-custom IEM's one of these days. The few published specs are consistent with what I hear: the Etymotics measure very flat except for a noticeable peak (that I'm not crazy about) in the 2khz region; and the other lines (Westone, UE, JH Audio) are pretty warm in the mid-bass relative to higher frequencies, with varying degrees of midrange de-emphasis. I'd like to see a flatter response curve with the ultra-high-end IEM's -- my ideal would be the Etymotic curve with an elevated lower end and smoother high end. Nevertheless, these products are revealing beyond belief, and the high level of noise isolation lets me take pristine audio to places I can't with regular cans. If you already have nice cans but don't have a set of IEM's, get your ears wet with some Westone 4's (literally: it helps to wet your ear with your finger first). You'll be hooked.

Tags: westone, utimate ears, jh audio