Sony IER-M9 In-Ear Monitor Review

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Sony IER-M9 In-Ear Monitor Review

I just listened to the IER-M7. It had great skill, but the balance was just a tad less than even. And being advertised as a musician’s IEM, the M7 would be more ideal for vocalists than other performers. So, I was curious to see what Sony would do with its higher priced model, the M9. Will it have a more neutral balance, and how much more talent will it display? Let’s find out in this Sony IER-M9 In-Ear Monitor Review.

Reviewing Sony IER-M9 In-Ear Monitor 

IN the BOX

Sony IER-M9 In-Ear Monitor ReviewSony IER-M9 In-Ear Monitor Review


One thing that musicians and frustrated commuters will appreciate about the M9 is the sound isolation. I thought it was great on the M7. But the M9 seems to even more effectively eliminate the sound of my boob-busting boss. And it beats my beloved Westones in this respect. They’re also easy to pop in. The memory wire has more of an elastic design, so you don’t have to mold the wire around your ears every time you put them on.

Sony IER-M9 In-Ear Monitor ReviewSony IER-M9 In-Ear Monitor Review


Sony has designed the M9 with 5 balanced armature drivers, which includes a magnesium super tweeter. The silk braided, silver coated copper cable (MMCX) feels durable, and the gold-plated plug seems solid as well.

Sony IER-M9 In-Ear Monitor ReviewSony IER-M9 In-Ear Monitor Review

The nice thing about Sony’s headphones is that you'll get a balanced cable in the package. It’s a 4.4mm connector, so you may need to get an 2.5mm adapter to hook it up to your player or DAC (unless you own a Sony DAP, of course). You’ll also find a freqload of ear tips in the box, as well as a fancy hard case. 

These buds take a some power to drive. I tested them through my phone to gauge how much juice they needed, and at about 70%, I had sufficient volume. But when I powered these things through my FiiO Q5, I had to crank it up quite a bit when comparing it to other IEMs.

I should also mention that your source could play a big role in how these buds sound. Switching between DACs/Amps made discernible differences in the sound profile. For example, I preferred the sound from my iPhone to my very lovable FiiO Q5. And I'm not going to a apologize for it.


Overall Impressions: Evenly balanced, detailed and easy on the ears.


Listening to pop, you’ll hear a perfect amount of bass presence. That is, it will satiate hedonistic audiophiles like myself without offending more civilized folks who expect a “neutral” sound. The bass has some dry grip too, giving tightness to fast tracks. And like the M7, the low end is nicely separated from the higher frequencies, offering a clean feel while still providing warmth to the mix. Unsurprisingly, listening to cellos in this range, the M9 conveyed a lot more texture and tone than did the M7. And in terms of transparency, I would put the M9 on par with any other best-selling IEMs in this price range.


The mids are present and more evenly balanced than they are on the M7. As a result, you’ll get a fuller picture of the track in this range, with vocals being placed more within the mix. That being said, I was a big fan of how good the layering of instruments was on the M7. And I don’t think the M9 one-ups it in this respect. Listening to guitar strums in the lower mids, the separation was no more skilled than it was on the M7. Still, you will get some more detail or nuance on these buds. I also felt a faster response on the M9. But that could have been the 3 lines I snorted before trying these things on. Listen, it was a jelly donut.


Nice clarity when listening to strings. But doing an AB test with the Campfire Andromeda, the M9 was slightly less transparent in this range. That being said, Sony has hit a great balance here. There’s good high frequency extension, but it doesn’t get too bright. Percussion, for example, had ample crispness and snap, but it avoided sharpness. And Miles Davis was bearable, if not downright enjoyable at times. So, for musicians, especially, who have these buds on for a whole show, it’s a fatigue free experience.


I’ve heard more spacious sounding soundstages at this price point. But the imaging definitely stands out as great, especially with respect to depth. It was like having ears in the back and front of my head. 


If you’re a musician looking for IEMs that can accurately represent your performance, these buds are a good way to go. And if you’re an audiophile looking for something neutral or relatively uncolored for critical listening, the M9 are a great choice as well. But if you're looking for a well-balanced headphone that also has a little panache, I'd check out the Empire Ears Phantom, the Campfire Andromeda and the Noble Audio Kaiser Encore

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  • Hi Geoffrey,

    I’m not sure about the case. But you might have some luck on

  • Just got these this week myself. They sound great. Do you know where I can find the hard shell travel case by itself? It’s great and I’d like another one.

    Geoffrey Moskowitz

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