I'm using this unit at my office with IEMs and an external microphone, for conference calls and music listening. It's been fantastic with an insane amount of power. I was initially worried when I saw an output impedance of 2.2 ohms, which may be a little high for BA IEMs (especially multi-driver). My Shure SE530 paired fantastically, without reducing the treble beyond it's normal timbre in any appreciable way. My real surprise is how well it pairs with pairs with my Campfire Orions! The Orion has impedance on the bass that's super low (4-7 ohms range!!), so almost any impedance whatsoever can really thin up the sound (although that's not necessarily a bad thing to a certain extent). However, 2.2 ohms seems like a magic balancing point.