Sony IER-M9 Review

Sony IER-M9 Review

Still recovering from the hullabaloo that constitutes CanJam NYC, today I’m nursing the world’s biggest hangover at the MajorHiFi Review Headquarters.  But fear not, dear reader, for I have the new Sony IER-M9 earphones to sooth my jangled nerves.  At $1499, this five-driver in-ear monitor has audiophiles chomping at the bit, but how does it stack up against its competition?

Sony IER-M9 Review

The Sony M9 comes in a swanky box with a deluge of accessories.  With thirteen pairs of eartips, a snazzy carrying case, and two cables, the M9 doesn’t skimp on the extras.

Utilizing a titanium shell, the M9 feels solid in my hands.  And, despite the relatively bulky appearance, they fit and wear well, with an ergonomic but lightweight build.

Cabling wraps around the top and back of the ear, with a springy memory wire that reminds me of FiiO cables.  Snapping into position when the earpiece sits in place, it easily flexes when I need to remove the M9.  One of the included cables terminates in 3.5 mm single-ended connection, while the other offers a 4.4 mm balanced plug.  Both cables measure a standard 4 ft (1.2 m).

Inside each earpiece, 5 Balanced Armature drivers – including a magnesium-diaphragm supertweeter – handle sound.  An integrated housing-within-the-housing helps to minimize vibration from each driver,  while a film capacitor seeks to minimize distortion.

Sony IER-M9 Review


Frequency Response:  5-40,000 Hz
Nominal Impedance:  20 ohms
Sound Pressure Level (SPL):  103 dB

From its specifications, the Sony M9 may boast some extension in the lows and highs as evidenced by the wide frequency range.  A low impedance of just 20 ohms allows this earphone to work fine with computers and cell phones, as well as personal audio players.  Sound pressure comes in at 103 decibels, delivering good volume without any amplification.

Sony IER-M9 Review

Low End

In the low end, the Sony IER-M9 delivers detail and energy in spades.  The sound, while natural and accurate, still feels fun and engaging.  Full and articulate, this sound benefits from a powerful and emotive bass.  Deep but not overblown or sloppy, the impact registers with a characteristic sharpness.


Tempered against the lows, the mids exude a sense of fidelity while never leaning too far forward.  The result – a rich, clean midrange – remains distinct from the rest of the frequency range while never seeming too far removed from it.  Contributing to this sensation, the mids exhibit no compression or distortion.  All in all, this midrange offers a fantastic listening experience that jives well with the overall sound of the M9.

High End

Impressive in its balance, the high end delivers excellent detail – but never strays too bright or piercing.  Even listening with my FiiO Q5 – a DAC/amp known for having a slightly bright sound – the M9 still sounds incredibly even-keeled.  Whether focusing on instrumentation or vocals, I can hear a surprising level of clarity and separation in these highs.


Deep but airy, the Sony M9 offers an impressive sense of soundstage – for an in-ear headphone.  While not quite so open-sounding as more expensive earphones from the likes of 64 Audio, the M9 still offers a rich and rewarding soundstage for its price – and even gives the Campfire Solaris something to worry about.  Each note stands in sharp contrast and there are solid swathes of space between each and every instrument.  That being said, on very, very intricate classical tracks, the soundstage may suffer just a bit, sounding a little bit narrow with more symphonic pieces.

Sony IER-M9 Review

Other Observations

The lightweight but comfortable design gives the Sony M9 a certain magic.  I can forget at times that I am actually even wearing earphones.  So comfortably do they fit that it really does feel like I’m lost in a world of sound at times.

This sensation grows when considering the fun and engaging sound profile of the earphone.  Its full but articulate lows give it some extra punch, while the meaty midrange and good high end keep the detail a’coming.

What’s more, the secure fit and wealth of eartips also lend a good deal of isolation to this earphone, making it all the easier to ignore ambient noise as you enjoy this immersive IEM.

Sony IER-M9 Review


If you’re looking for an all-around detailed sound that keeps music fun and engaging, the Sony IER-M9 won’t let you down.  With it’s robust sound profile and solid soundstage, this earphone offers a rare listening experience that cannot be discounted – especially at the $1499 retail price.

For folks who want a more analytical sound, the Campfire Solaris (also at $1499) might prove more rewarding with a slightly fuller sound (though the soundstage on the Sony might be just a little bit airier and spacious).

If budget is flexible, however, the Sony M9 could be ignored in favor of the Noble Audio Kaiser Encore ($1850), or the Empire Ears Legend X (at $2399).  Both of these higher-end options do much of what the Sony M9 does, but with better detail and even more engaging profile.

Final Analysis

At $1499, the Sony IER-M9 offer a solid option for longtime Sony fans and audiophiles in general.  A stone’s throw away from the highly-popular Solaris, this new upstart earphone delivers a more emotive listening experience than most other earphones at this price range, as well as an impressive soundstage.  While the sound may not be everyone’s cup of tea, it definitely deserves serious consideration if you’re purchasing an earphone near this price.

Get the Sony IER-M9 for the best price here:



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Carroll is a headphone junkie residing in Brooklyn. He's a huge fan of Grado, UK hip hop, and the English Language in general. When not testing audio equipment or writing, you'll find him taking photographs or fiddling with circuit boards. You can contact him at