Funny thing(s) about the Etymotic bassI had the same reaction about the bass response as most posts that I have seen. Even after a couple of months of break in, I found the bass thin, but acceptable when used with an Airhead amp.
Now that I am used to them, the bass from something like HD600s sounds overwhelming (but I like it!). I suspect 2 things about the Etys that make the bass hard to judge:
1 - I can't tell how loud I am playing them! I usually run them at such a low level that when I unplug the real world sounds harsh. That makes it difficult for me to judge if the bass response is down relative to anything else. If I turn them up until the bass seems right, I feel like I have more volume than I need over the rest of the spectrum. I am very protective of my ears, and usually keep the volume as low as I can.
2 - Some of the transient impact seems to be missing. I notice this at other frequencies also. Maybe my ear canals have a slow rise time (hold the cranial density jokes, please). Rounding of the square front end on a wave form can really affect the way a sound is percieved. The Etys will definetly go deep, but some of the percussive impact is lost somewhere. I even experimented with equalization at half octave intervals from 30 to 100hz. More quantity, but same perception of softened bass.
Those issues aside, I still find the ER4S phones amazing and wonderful.