Originally Posted by gnarlsagan
Thanks for that. The ER4S looks to roll off starting at ~50Hz, same as the ER-6.
Yes, but I would not describe the LF "roll off" of the ER4 as typical of other headphones. First, I don't think Headroom's response graphs for deep IEMs is as meaningful as for full size headphones. The graphs from Etymotic look different (http://www.etymotic.com/ephp/er4.html). At 30Hz the response is only -1dB and 20Hz around -2dB and relative to the rest of the curve, this is excellent bass accuracy. The 2k Hz bump is meant to mimic the response of the ear canal which isn't applied to the audio signal from the transducer when an IEM is deep in the ear. Taking all of this into account, the actual response at the eardrum is exceptionally flat from 30-10kHz.
From a listening point of view, I can describe the ER4 LF as extremely accurate for recorded material. I had long ago tested them with frequency range test tracks and could hear the 30Hz tone quite well.
Edited by ert - 10/3/12 at 3:27pm