To show you how the IERM stacks up relative to other top-tier custom-fit in-ear monitors, I’ll compare its performance with that of two leading competitors: the Westone ES5 ($950) and the JH Audio JH16 Pro ($1149).
Ultimate Ears In-Ear Reference Monitor vs. Westone ES5 ($950)
• The IERM costs $49 more than the ES5.
• The IERM is a three-way, 3-driver design whereas the ES5 is a three-way, 5-driver design.
• Both monitors are quite accurate in overall tonal balance. However, I would give the IERM the nod for overall neutrality and smoothness of its response curve. That said, however, let me also mention that the ES5’s very subtle touches of tonal emphasis in in the upper midrange and lower treble bands, enable it to reveal delicate low-level treble details a bit more effectively than the IERM does.
• Resolution levels between the two monitors are very closely matched, though in an absolute sense the ES5 may enjoy a very narrow edge. However, the IERM’s superior smoothness and top-to-bottom neutrality make it the more accurate transducer overall.
• One of the biggest differentiators between the IERM and the ES5 involves the construction of their custom-molded earpieces. Ultimate Ears has given the IERM’s solid acrylic earpieces, while Westone uses dual materials for the ES5 earpieces (solid acrylic outer shells with thermally-sensitive, soft feel material for the ear-canal section). Although the manufacturers have taken different design approaches, both monitors offer excellent comfort and very good noise isolation.
• Both the IERM and ES5 earpieces afford a simple, straightforward insertion process where you gently rotate the earpieces until they seem almost to “snap” into position, achieving a very good seal and a comfortable fit in the process. That said, I should point out the IERM is probably “first among near-equals” in terms of overall comfort and ease of use. Note, though, that the ES5’s soft-feel ear-canal sections, which—once they warm up—conform to exact shape of the wearer’s ear canal, yield significantly better noise isolation and quieter backgrounds than most in-ear monitors can provide.
Ultimate Ears In-Ear Reference Monitor vs. JH Audio JH 16 PRO ($1149)
• The IERM costs $150 less than the JH 16 PRO.
• The IERM is a three-way, 3-driver design, while the JH 16 PRO is a three-way, 8-driver design.
• Up to this point, the JH 16 PRO has been Playback’s reigning neutrality champ, so we were eager to compare the IERM to what we considered our gold standard. Here’s how that comparison plays out. Both monitors offer excellent neutrality and overall balance, though their voicing is not, strictly speaking, identical.
• The IERM offers powerful low bass and remains almost perfectly balanced from the bottom end all the way up through the midrange and lower treble regions, with just a hint of top end roll-off.
• In comparison with the IERM, the JH 16 PRO also offers potent bass, but with perhaps not quite as powerful a low-end presentation as the IERM; the JH 16 PRO’s mids and highs therefore sound just a hair more prominent than its low-end does. The JH 16 PRO’s treble response is beautifully extended and shows no signs of roll-off at all.
• If you consider the response curves of the IERM and JH 16 PRO side-by-side, the IERM sounds beautifully smooth and balanced, but just a touch more warmly balanced (because of its subtle treble roll-off). In turn, the JH 16 PRO sounds nearly as smooth and equally well-balanced, but with a subtle touch of midrange/upper-midrange forwardness, which I attribute to the fact that the JH 16 PRO’s bass range response is pulled back ever-so-slightly vis-à-vis its midrange and treble response.
• So which is the neutrality champ? I’d give the nod to the IERM, by the slightest of margins.
• Resolution: In terms of ability to resolve fine, low-level textural and transient details both monitors are good, but the JH 16 PRO enjoys a narrow edge (in part because its extended but unexaggerated treble response makes details easy to discern, yet without imposing any sort etched or artificially “spotlighted” sound).
• The earpiece designs of the IERM and JH 16 PRO are conceptually similar, as both use solid acrylic earpiece designs. Yet in terms of execution the IERM and JH 16 PRO earpieces are—at least in the case of my review samples—functionally different. My JH 16 PRO are extremely easy to fit and remove (the best custom-fit models I’ve tried in this respect), but they do not offer the last word in noise isolation, which suggests to me that the earpieces may fit a bit more loosely than some competing custom-fit earpieces do. In contrast, the IERM’s offer a subtly tighter fit (yet one that is still quite comfortable, once you get them properly inserted) and concomitantly better noise isolation (UE claims -26 dB for the standard versions with acrylic housings, though a special-order, soft-silicon version boosts isolation to a whopping -32 dB). So good is the UE fit that I would rate it second only to the Sensaphonics 2MAX monitors in terms of noise isolation, which is most impressive.