Originally Posted by T.R.A.N.C.E.
Even the most power hungry IEMs will be completely fine with the ZX1 even very low impedance iems are fine. Its only high impedance headphones that are not driven well. Low impedance headphones are fine with the ZX1, like Senn HD25 or Koss Portapro or AT M50 etc. Basically anything under 100 ohms with decent sensitivity is fine.
Impedance has to do with power delivery, but not the delivery of the level of sound. That's dB/mW or SPL. Also, some low Impedance multi BA IEMs depends on output impedance, which was the problem with the AK100, and ZX1 may have high output impedance(since typical Sony player output is typically high) relative to low impedance multi driver BA IEMs. The output impedance will affect the multi BA crossovers which is impedance. Crossovers are filters of frequency range of each driver, if you mess with that, you will not get the sound of the IEMs intended design, so watch out for output impedance.
Edited by SilverEars - 4/20/14 at 12:33am