I broke in the EarSonics via a robust headphone output for several days before doing any serious listening (as per the manufacturer’s email instructions). I did cheat and give them a brief listen before break-in, using the double-flange tips, and thought to myself, “These sound like a pair of Etymotic ER4-SRs,” meaning they were clear, very neutral, and perhaps not bass monsters. But after break-in I had to revise my opinion of the S-EM9’s bass response (besides burn-in, I switched the tips)—these IEMs have the most extended and controlled mid and low bass of any universal in-ear I’ve heard. Not only is the bass tight, powerful, and nuanced, but the S-EM9s also produce a large, evenly proportioned, and three-dimensional soundstage with excellent image specificity. Their overall harmonic balance is quite neutral, especially considering their exceptional bass extension. Listening to Chance the Rapper’s “Blessings” via Tidal, I was impressed by how little effect the big low bass had on the rest of the spectrum. Even sudden bass transients didn’t color or mask the vocals or instrumentation.
Midrange clarity and decipherability through the S-EM9 were exemplary. Whether it was a soprano or a baritone voice, timbre was exceedingly natural and relaxed, but still delightfully clear. Listening to a recent musical discovery, Will Hoge’s superb song “Through Missing You” from his Anchors album via Tidal played back via the Astell&Kern KANN player, the track had a level of intimacy and verisimilitude that drew me in completely. Also, the electric and acoustic guitars had just the right combination of crunch and harmonic complexity. Give a listen to Hoge’s “Not That Cool” from his Blackbird on a Lonely Wire album, and I dare you not to try not to dance.
The S-EM9’s soundstage size and dimensionality was not quite as spacious as with some in-ears, such as the Empire Ears Zeus, but slightly larger than what I hear from the Ultimate Ears Reference Remastered. On the other hand, the S-EM9’s image specificity was especially good, not only in lateral placement but also in back-to-front layering and edge definition. On Mike Posner’s “Red Button” from his One Foot Out the Door EP, it became clear that the synth exists in a much larger sonic space than do the vocals, and it sits much farther back in the soundstage. Moving to a very different musical genre, on my DSD5.6 recording of the Boulder Philharmonic performing Benjamin Britten’s Peter Grimes, the S-EM9/KANN combination did a superb job of preserving the layering and distances between the front row string section and the winds further back on the stage.
As with full-range loudspeakers in a completely sealed room, there is a point where low-octave energy from an earphone can “box” your ears on an especially bass-a-licious track by building up pressure and leaving that pressure no place to go. Some in-ears reduce this effect by way of a small opening, so your ears are not in a completely sealed environment. The S-EM9 can produce so much low bass energy that on some selections, particularly those from modern bass-centric pop divas such as Katy Perry (e.g., “Chained to the Rhythm”), the pressure buildup can be noticeable if not worse. While that buildup never reached the point of pain, I did very occasionally need to re-seat the S-EM9 to alleviate pressure.
When compared with the similarly-priced Jerry Harvey Roxanne CIEM ($1795) the S-EM9 delivered more extended, detailed bass and sub-bass. After adjusting the Roxanne’s bass controls for a richer mix, the Roxanne did generate more midbass than the S-EM9 but not more low bass. The Roxannes were slightly more comfortable (they are a custom fit, after all), but both IEMs were comfy enough for multi-hour listening sessions. While both in-ears imaged quite well, the S-EM9 had slightly more specific image placement with greater sense of three-dimensionality.
Comparing the S-EM9 to the original version of the Astell&Kern AK T8iE ($999), I noticed that the latter produced a slightly tighter soundstage, but it wasn’t quite as expansive. Having only a single dynamic driver, the Astell&Kern takes a very different approach than the S-EM9, but the two earphones had an eerily similar harmonic balance, except for the bottom octave, where the S-EM9’s superior control, power, and articulation bested those of the AK T8iE. Comfort-wise, they were quite similar, as well. Even though the AK T8iEs were smaller and a bit lighter (both are quite light), once in place in my ears I had no comfort issues with either model.
Switching over to the recently reviewed Ultimate Ears 18+ Pro CIEMs ($1500), the most obvious difference was the fit. The 18+ are a custom fit and once they’re seated it’s “game over” compared to any universal-fit design. The 18+ had more complete isolation, and generated a huge soundstage. The 18+’s bass control and extension also gave the S-EM9 stiff competition, but the UEs were still edged out by the S-EM9 due to the S-EM9’s ability to produce slightly more low bass “puff of air” impact. Both produced a gloriously delicious midrange on songs such as Laura Marling’s “Soothing” from her Semper Femina album.
The EarSonics S-EM9 ranks as the best-sounding universal in-ear I’ve heard that does not have a CIEM version available. But at a price that is usually reserved for custom in-ears and some mighty fine full-sized headphones, this universal-fit in-ear has stiff competition. Still, if you listen to music with deep bass and are in the market for an in-ear with exceptional extension combined with a surprisingly neutral harmonic signature, the S-EM9 may be exactly what you have been seeking.
Specs & Pricing
Type: Balanced-armature, universal-fit in-ear
Driver complement: Nine drivers with three-way crossover
Impedance: 38.5 ohms
Frequency response: 5Hz–20kHz