Truthfully speaking, I just don't think the bass in either the E3c is Ety ER-4 is quite enough for their price class. There's a "sacrifice" that you make when using canalphones, and despite many people's unwillingness to admit that they made a sacrifice for size and portability, it is definitely there.
ER-4 is extremely detailed, but completely lacking in a realistic bass. Yes, I understand how the note of the bass is all there, it's just lacking visceral impact. How does that excuse it from not having a realistic bass though? If our full-size headphone had the same type of bass response as the ER-4, we would, without any hesitance, cry out, "Where's my bass?!" So where does this double-standard for the ER-4 come in place?
E3c is a little bit better, but just a little bit. E3c has a mid-bass boost that gives you a more exciting mid-bass with at least some more visceral impact, although once you start reaching in the low bass frequencies, it's very clear that the E3c is unable to reproduce those frequencies with any sort of impact as well. I think when you reach into this deep level of bass, ER-4 does a better "note representation"; meanwhile neither has any visceral impact left to give.
E5c is really the only one that has the bass impact to rival a full size headphone. In fact, out of all the headphones I've tried and own, I would only take my CD3000 over the E5c. If I had to pick between only one to keep, I would still keep the E5c due to its portability and versatility. However, you do pay a very dear amount of money for the E5c... there's a price to pay for miniaturization.
A realistic bass to me, *has* to have visceral impact. I mean, if you were at a concert and the drummer's drum gives you just notes, and no physical vibration whatsoever, what would that feel like? Wouldn't that be a bit odd, a little bit strange? What if you're at a jazz concert and the bass strings give you no physical involvement? Anyway....