helloimkonRest assured, I've used them with some of the most sensitive IEMs out there (e.g. FitEar 334 Ultrasone IQ, FI-BA-SS), and even then volume attenuation is quite manageable, if that's what you're concerned about.
PolygonYeah, that is what I am worried about. Thanks for the reassurance.
@CEntrance I am going to use them with my IEMs, namely the Ultimate Ears Superfi 5 Extended Bass and some other VSonics earphone.