Rank #11: EarSonics S-EM9



Perfect Seal Deca ($1450)
Perfect Seal’s Deca and the S-EM9 have little in common; where the S-EM9’s frequency response goes up, Deca’s goes down – and vice versa. The result of two very different intended tunings. Deca was designed to sound natural, with a focus on a faithful reproduction of instruments; especially string instruments. The S-EM9 in turn is tuned to sound both fun and precise, based on an engaging bass and high resolution.

Deca’s stage is slightly more spacious than the S-EM9; particularly its width. It’s also a bit airier, as result of its laid-back bass. But when it comes to the quality of the stage, the S-EM9 pulls ahead; its imaging is more precise, as is its layering. The result is a more focused image, and a more precise instrument positioning; a more three-dimensional picture, despite its smaller proportions.

The S-EM9’s musicality starts with its bass, a low-reaching, and deliciously impactful bass. Deca’s bass equally has proper low-end extension, and there’s nothing wrong with its speed. But it isn’t tuned for fun, as it’s significantly lighter than average – it’s a bass for people that want their bass to behave. In tone and definition there isn’t much to set them apart.

As both have a modest center midrange bump, they share some similarities in their midrange. It isn’t overly forward, thick, or full. But there’s a nice bit of density in the vocal presentation, that gives them size and solidity. But it’s in the upper midrange where they truly depart – Deca’s turn to shine. Deca’s instruments sparkle and shimmer, beautiful in tone; the S-EM9 isn’t quite as accurate in its timbre. It’s a bit warmer though, but also leaner.

Their trebles converge again in score, but with different qualities. The S-EM9’s is articulate, detailed, and quick; Deca’s are warmer and more accurate in tone. Overall, Deca’s treble is more pleasing in tone, but the S-EM9’s are a good deal more precise, not in the last place because of its superior extension.

Noble Katana ($1849)
Sporting 9 BA drivers, there isn’t an iem that comes closer to the S-EM9 in design. Plus, the two iems share more than their driver count. They also seemed to be designed from a somewhat similar philosophy; an enhanced bass and lower treble reveals a similar yearn for musicality. Nevertheless, their presentation is more different than similar, with Katana having greater balance throughout its signature, and the S-EM9 generally being more precise.

Katana’s stage is significantly larger, especially its width. It’s also a bit cleaner due to its upper treble peak; the S-EM9 has a warmer tone running through its stage, partially due to its stock cable. While the S-EM9 can’t quite match the Katana in its overall dimensions, it takes advantage of several factors in its presentation: a leaner note size, higher resolution, and more precise layering – besting the Katana in separation as result.

Although both iems share an engaging bass, they’re different variants. Katana’s bass is a closer resemblance to classic BA-driven bass, being tighter and quicker. The S-EM9’s bass in turn reaches a bit lower, and sounds more natural in its delivery; its speed and decay. In addition it’s a bit more natural in tone. Both share similar definition.

The midrange is where they more steadily depart. Katana’s vocals are more forward, and larger in size. There’s also a greater balance throughout the vocal range, where the S-EM9’s top end is a bit more attenuated, resulting in a compacter size. Similarly, this affects the body of instruments. And as a result of the relatively more enhanced treble, Katana’s midrange has greater clarity. The S-EM9’s midrange on the other hand is a bit warmer in tone, and smoother.

Similarly, the Katana’s treble is a bit brighter in tone. They might share a lower treble peak, Katana has an upper treble peak just for itself. The result is overall more clarity in the signature, and a more upfront detail presentation. The S-EM9’s treble is a bit smoother, as well as quicker. In addition, its treble extends significantly further. While their transparency is similar, the S-EM9 has greater resolution.


‘Musical’ is one of those awesome semi-audiophile definitions to characterize a signature, even though it’s a bit empty as a term – it’s highly personal and subjective by nature. By definition, everyone will have their own interpretation of what musical means. In a practical sense, it’s usually used to point out an iem has sufficient bass, in contrast to being ‘analytical’ or ‘technical’. But who says musical can’t be precise?

The S-EM9 is EarSonics’ own interpretation of musical – musicality based on precision. It displays top tier performance across the board: excellent imaging, resolution and separation. The S-EM9 makes it very easy to follow the music, to see the picture as a whole. But to be labeled as musical, just precision won’t suffice; you’re going to have to add some pretty dynamic bass and treble to the mix. Sure enough, a punchy bass drives the music, while an articulate treble enhances its rhythmic feel – as if it’s made to sound fast, even when standing still. It’s the reason I like to play fast electronic music with the S-EM9. Not that it doesn’t work for other genres, but it’s that combination of compact notes and high precision that lets the music dance in front of your eyes.

While I’m well aware I need to keep cable talk to a minimum, the S-EM9 deserves better than its stock cable. I can speculate and say it might be due to it’s higher than average impedance, but I can’t say for sure. I can however say it doesn’t make the most of its excellent top-end extension. But whatever the case; when properly paired, the S-EM9’s precision is hard to beat. Add that punchy bass, and this isn’t only EarSonics’ definition of musical – it’s also mine.


EarSonics S-EM9
+’Musical’: bass and treble tuning
-Tonal accuracy

The scoring can be viewed in the introduction post.

Manufacturer website:

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About Author

Nic is currently in pursuit of a PhD degree in social neuropsychology, while trying not to get too distracted by this hobby. In pursuit of theoretical knowledge by day, and audiophile excellence at night. Luckily for him, both activities are not mutually exclusive which helps to lighten the workload. Always on the go, Nic's enthusiasm for hi-fi is focused on all chains of the portable system: iems, cables and daps.


  1. I have a chance to pick up sem9 for 40% off. Could you let me know whether they are suitable and is there anything better in around £800 for folk, classic rock and pre 2000 pop music. Thank you.

    • Hi there, it’s a bit hard to predict since it depends on preference. Personally I enjoy the S-EM9 especially for pop music. It will also work for folk and rock, but the vocal presentation is not particularly forward and present, it is more a linear balanced presentation where the instruments are in line with the vocals. So if you are looking for a deeply powerful, emotional vocal experience they might not be ideal. But in general I would consider it an allrounder.

      • Thank you for your replay flinkenick. I really enjoy the sound of S-EM9 however, as you pointed out vocals can sometimes be on a quieter side especially in older recordings. I am looking to upgrade the cable now and given your expertise I would really appreciate if you could recommend me some options around $300 that would enhance or better separate the mids without changing overall sound signature. At the moment I am using stock Westone cable that helps a little. Thank you.

    • Apologies for the late reply, it seems my notifications have been going to spam so I missed the past comments. I guess a good allround player would be the DX200, as it is versatile and neutral in tone. The LPG is also great if you can find one second hand, or maybe an AK player at a good deal. But it really depends on preference, some might prefer a warmer or brighter sound so it would be good to figure that out for yourself first.

    • The Velvet and S-EM9 both share an enhanced bass and lower treble. But the Velvet’s bass is focused mostly on sub-bass, where the S-EM9’s is more balanced between sub- and mid-bass. As a result, the Velvet’s bass is punchy and impactful, but its mid-bass is not very natural in tone compared to the S-EM9. The S-EM9 has a bump around 1 Khz which brings its midrange a bit more forward and gives it more focus. By comparison the Velvet’s midrange is thinner and laidback, especially since its lower treble around 7 Khz is more articulated, while it sounds brighter due to a more elevated 12 Khz peak The S-EM9 has great extension, but the upper treble is less prominent. Accordingly, it sounds smoother and closer to neutral, where the Velvet is brighter and more energetic.

  2. Some advice for people wanting to get the Sem-9. Upgrade your cable immediately. A simple SPC cable like the Thor SPC will do wonders for the soundstage and clarity of the IEM.

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