We started our auditions by comparing the E4cs with the company's $179 earbuds, the E3cs. At first we didn't think the sound was all that different, but as we listened, we noted that the E4cs sounded a little weightier, so baritone saxes sounded deeper, stand-up basses had a richer, woodier tonality, and male voices had more, ahem, testicular authority. Over extended listening sessions, we became aware of the headphones' superior low-level detailing, which allowed us to hear subtle reverberation. Also, the "spaces" between the instruments were more apparent. Sound isolation was excellent in both models, approximately on a par with that of the best active noise-canceling headphones we've tried. The E4cs' bass was accurate and clean, but if you're a glutton for bass and need relief from noise, check out AKG's K 28 NC noise-canceling headphones, which have tons of bass.
We next compared the E4cs with our longtime reference in-ear headphones, the Etymotic ER-4Ps ($330). Well, all right, we have a new winner! The E4cs sounded more open, less inside our head, more dynamic, and a tad richer than the ER-4Ps. The Etymotics are still great headphones, but on Lucinda Williams's white-hot new CD, Live @ the Fillmore, the E4cs put us in the first row of that legendary venue. It was amazing how clear the sound was. At the same time, the vocals' natural warmth was preserved, and the bass power and definition were first-rate. The ER-4Ps' cooler, more analytical presentation had oodles of detail but didn't sound as rich.
The E4cs' phenomenal performance leaves little room for complaint, but a few nagging design details are worthy of mention. We wish, for instance, that Shure had included a shirt clip like the one that comes with the ER-4Ps; the E4cs' thick, dangling cable often feels like it's about to yank the earpieces from your ears. And the E4cs' recommended insertion process--looping the wires behind and over the ears--can be an involved maneuver, especially for those who wear their hair long. A final gripe is the E4cs' tiny L and R earpiece labels, which are hard to decipher under low-light conditions; color-coded earpieces (similar to Etymotic's) would have made for easier distinction.
That said, problems with the Shures are firmly restricted to the nitpicking column. The bottom line is that the ultracompact Shure E4c earbuds sound flat-out amazing. They're the best in-ear headphones we've heard to date.