Of course, I'll only speak for me, but I've been listening to both of these earphones since I got my E4c, and have been doing more back-and-forth with them today, and whether I'm listening to Nick Drake, the John Pizzarelli Trio, Soul Coughing or Mahler, the E4c is
to my ears all of the following, relative to the E5c:
- Better in terms of tonal continuity. Whereas some might see the two-driver configuration as a plus, I don't think it's necessarily so. As with my AKG K340 (which I also like, and, like the E5c, is also a two-way configuration), there's an occasional sense of disjointedness with the E5c that I think may be due the crossover and the necessity of melding two drivers to present as one. This is most apparent to me with jazz piano trios. With the E4c (as well as my ER-4S/4P), they're always in the same space, same place, and never do I get the sense that the bassist is playing in a different acoustic than the pianist, which I sometimes get with the E5c.
- Quieter (in terms of noise floor). The E5c exhibits hiss with all but a few amps I've tried it with. With as much emphasis I've put on keeping my rigs quiet (in terms of background noise)--from dedicated lines to power conditioning--the hiss is an issue, and noticeable between tracks, and during quiet passages, with most rigs I use it in.
- Better in terms of bass control. As far as earphones go, there's no doubt that the E5c's bass is alluring, and I was relatively happy with it. After listening to the E4c, however, the E5c sounds loose in comparison.
- Better in terms of treble extension. Where as I can see how some might hear the E5c and think it softer up top than ideal, I'd be much more surprised to see such an assessment of the E4c.
These are my opinions, and how
I hear 'em. To me, the long run is not going to have as much back-and-forth between the E4c and E5c, but between the E4c and Etymotic's products. As someone else already pointed out, if you really dig the E5c, then the Etymotic ER-4P/4S may be a hard sell. But I was one of the folks who liked the relatively impactful bass and body of the E5c, but felt it came at the expense of the detail and resolution of, say, the ER-4S. I have both the ER-4S and ER-4P, and, whereas I'd occasionally turn to them in lieu of the E5c when I needed a bit more air and detail, I've not had to do that since I got my E4c--for me, it's what I wanted from my ER-4S/4P, but with much more solid bass response and a more impactful presentation overall.
As for how
loud they can play: it wouldn't surprise me if the E5c can ultimately reach higher SPLs, but, since I've turned the E4c up as loud as I can take it, without a hint of strain on the E4c's part, its maximum sound pressure levels are far beyond my reach, so I can't comment on how the two compare in that regard.
At both last month's Detroit Mini-Meet and last weekend's Ann Arbor/Detroit Meet, the E4c went over
very well, and certainly not due to any prodding from me for the folks to dig it. I just left the earphones out with some spare foamies, other eartips and alcohol pads, and let anyone who wanted to give it a hear do so. At the Mini-Meet, chosen1 compared the E5c and the E4c. At last weekend's Meet, I think it was rcgrant who asked me if he could borrow both the E4c and ER-4P to compare. Several others gave the E4c a listen, too, but these two guys are the only ones I actually saw actively doing back-and-forth comparisons with another earphone (the other guys might have done the same, but I didn't see them doing that).
There'll always be folks who prefer the E5c to the E4c, and the ER-4S/4P to either, but, for me (and I think this will eventually be true of many others, too), the E4c is my go-to earphone until I hear a better overall earphone for me.