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The image shows the right Sennheiser IE 900 earbud resting on top of the greyish case with individual serial number, atop a wood desk.

Sennheiser IE 900 review

This set of IEMs costs more than your phone, and maybe your computer, but at least it'll never become obsolete.

Published onJuly 20, 2023

Sennheiser IE 900
The bottom line
Sennheiser really nails it on excellent isolation, proving that you don't need apps and noise cancellation to quiet the world. In a highly digital world, the aluminum housing reminds us that humans still like nicely made objects. The in-ear monitors provide great sound quality, but one wonders if the IE 900 is merely an exercise in prestige or actually worth the price.

Sennheiser IE 900

Sennheiser really nails it on excellent isolation, proving that you don't need apps and noise cancellation to quiet the world. In a highly digital world, the aluminum housing reminds us that humans still like nicely made objects. The in-ear monitors provide great sound quality, but one wonders if the IE 900 is merely an exercise in prestige or actually worth the price.
Product release date
June 1, 2021
Original: $1,299
1.25m (per cable, three total)
4g (earbud), 24g (earbuds with cable)
Model Number
IE 900
What we like
Excellent sound quality
Build quality
Detachable cables
What we don't like
Sound is highly fit dependent
SoundGuys Rating
User Rating
Rating Metric
Our Rating
User Rating
Isolation / Attenuation
Durability / Build Quality

My parents used to own a $500 car. That car drove me to school as a kid, picked up groceries, and it definitely stalled at intersections. Once you start seeing earphones for $1,300, consider that as used car territory. Even with inflation, I ask: is nearly $1,300 wise to spend on in-ear monitors (IEMs)? No, it’s not wise, but it’s kind of fun. The German-manufactured Sennheiser IE 900 works well and effortlessly (unlike that aforementioned Ford), but the market is full of heavy hitters. We spent a week with the IE 900, so let’s see if the premium IE 900 justifies the cost.

Editor’s note: this article was updated on July 20, 2023, to add the Sennheiser IE 200 and Sennheiser IE 600 as Alternatives, an FAQ about the Sennheiser IE 600 sound compared to the Sennheiser IE 900, and to update the formatting.

Audiophiles interested in the prestige element of gear will like the upgraded IE 900 experience. People with money to burn on portable audio will be rewarded with very nice in-ear headphones.

What’s it like to use Sennheiser IE 900?

Part of the IE 900 experience includes taking the time to enjoy the tactility of the earphones. The lightweight aluminum milled housing slips into the ear like a ring on your finger. After all, this is a marriage of sorts between you and Sennheiser, in the way that Sennheiser supplies signed paperwork and you share your finances. Getting the right fit is important because the majority of the IE 900 features hinge upon it. If the supplied ear tips do not fit you, I urge you to try a third party option. A poor fit negatively impacts isolation, and by extension audio quality.

The Sennheiser IE 900 coiled up in a hand.
Wired listening offers a consistent, high-resolution listening experience.

In my ears with the size small foam ear tips, the IE 900 is comfortable, but it sits pretty deep in my ear canal, which creates a feeling of pressure. The silicone ear tips are less obtrusive and I can leave them in for longer without much fatigue, though they don’t isolate as well. Despite having a similar look to the Sennheiser IE 300, the IE 900 feels more comfortable for longer periods. With this style of earphone, I notice that when I bob my head to a song’s bassline, the sound noticeably alters because movement shakes the IE 900 out of place. Even though the fit is secure, it’s very sensitive to tiny changes.

Prestige is the first word that comes to mind, while opening the box for the IE 900. Sennheiser places a certificate of authenticity within each box that promises this set has undergone a quality check, and each pair of transducers has been hand-selected. You get a signature (in ink) and the handwritten serial number of your in-ear monitors on the certificate, as well as on the somewhat hefty carrying case. The case works well, but it’s too clunky to fit anywhere but your desk, backpack, or large purse.

A man from the side wears the Sennheiser IE 900 earphones outside in front of greenery.
The IE 900 wraps over your ear to stay put.

Six sets of ear tips (three made of foam and three made of silicone) come in the box along with a cleaning tool with a microfiber cloth, an optional lapel clip, and three choices of hardy para-aramid cables round out the bundle. Generally, I use the standard 3.5mm connection for my lossless audio listening. Sennheiser also ships it with 2.5mm and 4.4mm cables. The MMCX cables satisfyingly snap into place. Subtle L and R indicators on the housings direct you which goes where. The cable has a gentle memory wire that holds it in place when bent and curved over the top of the ear.

The IE 900 can work with the Bluetooth Sennheiser IE BT Connector for portable playback, which we reviewed with the IE 100 PRO Wireless. While you can use the IE 900 to stream wireless audio, it sort of defeats the purpose of the product. For most folks, casual listening doesn’t require high-resolution audio, and the individual who purchases an audiophile product like the IE 900 looks for the features like the extended 5Hz to 48kHz frequency response, which Bluetooth can’t support.

Does the Sennheiser IE 900 have good isolation?

Yes, isolation is great with the Sennheiser IE 900. You don’t get any new fangled active noise cancellation (ANC), but that just means there’s one less point of failure to worry about.

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Isolation costs you zero power (it’s nice to not charge headphones, right?), and great isolation results from solid engineering. You can effectively block out anyone on the bus trying to talk to you. You won’t even know if bus neighbors are chatting up a storm because the IE 900 successfully isolates you via the effective physical barrier that comes with a well-sealed ear.

Typically isolation does its best work with high-pitched sounds, and the Sennheiser IE 900 is no different. It does, however, sweep the spectrum with at least around a 10dB reduction of sounds across the board and up to around 45dB in the high mids and treble.

How does the Sennheiser IE 900 sound?

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The $1299.95 question is, how does the IE 900 sound? It sounds good. It sounds like if you combined a consumer frequency response with a studio frequency response. The bass and midrange response hews closely to our consumer target curve. Meanwhile, the upper-mids and treble resemble our ideal studio frequency response, with some light under-emphasis. This yields a highly pleasant listening experience, nearly devoid of any notes drowning out others. If anything, you will hear quirks and interesting mixing decisions laid bare with this frequency response.

The IE 900 frequency response ranges from 5Hz to 48kHz. While that number looks impressive, the vast majority of people can’t hear above or below the 20Hz to 20kHz range. Some of us like the extended response because we think we can perceive it. Indeed, some people can “feel” those sub 20Hz low frequency and infrasound bass frequencies even if their ears and brain can’t interpret them. Meanwhile, only a few unusual (and likely, young) people can hear sounds above 20kHz — think dog whistle frequencies. Try testing your hearing.

Even if you could perceive those high and low frequencies, there wouldn’t be much to hear, because that’s not where our music lives and not what standard recording equipment registers. The 5Hz to 48kHz range isn’t necessary, just like buying a Bugatti hypercar capable of reaching illegally high speeds—though, at least you know you could experience extreme speeds if you were allowed to. You can’t even experience 48kHz.

Lows, mids, and highs

Bass frequencies from the kick drum and bass guitar sound just loud enough to hear in the song The Ghost with a Hammer in His Hand by Help Stamp Out Loneliness and don’t mask other frequencies. For the bass frequencies, ensure the buds fit all the way in your ear because if they shift the bass disappears. Just when you think the IE 900 earphones are in, push each in further. Honestly, it feels just short of surgical.

A hand holds the Sennheiser IE 900 earphones without the cable attached.
A detachable cable means you can use the IE 900 for years without having the buy a whole other new set if the cable fails.

Listening to a track like The Ghost with a Hammer in His Hand could easily cause listener fatigue if played through a cheap set of earbuds, with trebly organs and synths in the mix. Instead, the IE 900 pleasantly relays keyboard sounds thanks to the slight treble under-emphasis relative to our studio headphone curve. One side effect of the under-emphasis is that some female voices sound inaccurate as if they lack detail. D. Lucille Campbell’s low alto voice lacks an equivalent emphasis on some of the higher-register frequencies.

Picking a more guitar-focused song, Sunlight Bathed the Golden Glow (Remastered) by Felt once again reveals that the IE 900 is fully capable of reproducing treble notes with just the appropriate amount of emphasis. Maurice Deebank’s meandering lead guitar is reproduced faithfully. Since there’s very little auditory masking here—especially relative to consumer-oriented headsets—the IE 900 reveals interesting artifacts of production. It’s more obvious the producer used a filter to remove the singer Lawrence’s sibilance (at 2:04 for example). If you are an analytical listener the IE 900 can highlight your favorite band’s flubs or quirks.

Should you buy Sennheiser IE 900?

The Sennheiser IE 900 dangles over a Newton's Cradle on a wood desk with a plant in the background.
The aluminum housing feels premium and has the added advantage of a lightweight, robust build.

For the individual who has everything else, the IE 900 sounds great. For the rest of us, it’s a prestige product that has cheaper alternatives that get you 90% of the way there.

There is something strange about listening to music on earphones that cost more than the ones the musicians used when producing said music. The Sennheiser IE 900 experience is complex because if you casually listen, it sounds about as good as very good earphones. If you actively pay attention to what you hear, suddenly, the clarity of all instruments in different frequencies becomes noticeable.

With that said, you can’t talk about the Sennheiser IE 900 without acknowledging the price tag. Ordinarily, as consumers we all look at a product and say, well I wish it had X, but at this price, I understand why it’s not there. You don’t have to do that with the IE 900. The price begs you to be critical. The IE 900 should be even more comfortable, and wrapping a cable over your ears feels annoying. For basically $1,300, you should get something approaching custom-molded earbuds.

In a world of compromises and rational decisions, there’s something to be said for supporting manufacturers trying to make the best audio gear. For that reason, Sennheiser deserves credit.

Sennheiser IE 900Sennheiser IE 900
Sennheiser IE 900
Excellent sound quality • Build quality • Detachable cables
MSRP: $1,299.00
Sennheiser really nails it on excellent isolation, proving that you don't need apps and noise cancellation to quiet the world. In a highly digital world, the aluminum housing reminds us that humans still like nicely made objects. The in-ear monitors provide great sound quality, but one wonders if the IE 900 is merely an exercise in prestige or actually worth the price.

Sennheiser IE 300 vs Sennheiser IE 900: Which is best?

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You may ask yourself if the Sennheiser IE 900 is worth the extra $1,000 over the Sennheiser IE 300. That’s a sane question, and for most people, the answer is no. Then again, “most people” is not the target demographic for the IE 900. Most people are happy with the already low distortion of the IE 300, and the solid-sounding frequency response. Additionally, most people are happy if the transducer is made in Germany on the IE 300 and the rest of the labor is performed in China.

The Sennheiser IE 300 shot with a shallow depth of field, rest on a synthesizer.
You don’t get sleek aluminum housing on the IE 300, though the shape is somewhat similar to the IE 900.

The IE 900 is for that other tiny percentage of people who want an even lower distortion, even if the difference is scarcely perceptible. These consumers value knowing that the whole of the IE 900 is made in Germany with double-tested, hand-matched transducers. This has to do with both the element of prestige as an owner, but also an invitation for you to try out Sennheiser doing some of its best work. The IE 900 is the earphone equivalent to a car manufacturer deciding to build and sell a concept car, rather than selling the more reasonable, sane version—the IE 300 in this case.

Anecdotally, the IE 900 fits my ears better, despite looking very similar in shape. Most of us ought to pick the IE 300. Those who choose the IE 900 (hopefully) understand the law of diminishing returns and are willing to pay extra to get those minute differences.

Sennheiser IE 300Sennheiser IE 300
SG recommended
Sennheiser IE 300
Build quality • Lightweight • Plentiful, useful accessories
MSRP: $299.00
The Sennheiser IE 300 is a set of earphones for those who take music seriously, and everywhere. With a headphone jack and excellent passive isolation, if you want a portable lossless music experience, get these. Listeners who want more features and a more diverse package should turn to other wired earbuds with control modules or the plethora of true wireless options that cost far less than the IE 300.

The Sennheiser IE 900 is made of smoother materials for the housings than the Sennheiser IE 600. They’re both good. Check out how they sound compared to each other.

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What should you get instead of the IE 900?

The wired cable plugged into the Sennheiser IE 100 PRO with ear tips and cloth bag, sitting on a wood surface.
With the lightweight and low profile buds, and the over-ear cabling, the IE 100 Pro stays put.

The clear answer is to buy the Sennheiser IE 300 instead for $281 at Amazon. If you have a tight budget, try the also excellent Sennheiser IE 100 PRO Wireless ($149 at Amazon). Both sets of earphones have similar frequency responses to the IE 900. The IE 300 has a bit less treble emphasis than the IE 900, but it performs very well. Meanwhile, the IE 100 PRO Wireless has a touch more treble emphasis. It feels less comfortable over an extended period of time than the IE 300 and IE 900, but keep in mind it runs for about $150.

You’re welcome to check out the Sennheiser IE 200, which hits the sweet spot for a lot of listeners. Gone is the case, and most of the lux goodies you get with the IE 900. What stays is a nicely tuned set of IEMs made from decidedly more pedestrian plastic. These go for only $119 at Amazon.

A man faces left with a beanie on wearing the Sennheiser IE 600 with the cable wrapping over his ear.
Jasper Lastoria / SoundGuys
The IE 600 is made from an usual and lightweight metal.

Lastly, the Sennheiser IE 600 is still pricey ($599 at Amazon) but less so than the IE 900. These are made from a 3D printed material used in scientific applications in space. Like the IE 900 you get a carry case, certificate, and a pleasant tuning. If you can get along with the unusual texture, it’s worth a look.

What’s great about choosing one of the other products in the IE series is that cost-cutting measures haven’t ruined sound quality or frequency response. You don’t get the full suite of memory foam ear tips with the IE 100 PRO Wireless, but you can buy those for under $20. There’s a Sennheiser IE for everyone.

Frequently asked questions about the Sennheiser IE 900

Fortunately Sennheiser ships the IE 900 with a cleaning tool. You’ll want to remove the eartips, give them a gentle wipe with a damp cloth. Stick with the cleaning tool for the most part for other areas around the driver cover. If a spot is stubborn, maybe just leave it. You don’t want to damage pricey earphones. Otherwise, we have a more general guide.

For the most stable fit, you’ll first check that you’ve got the red stripe (which indicates it’s the right bud) ready for the right ear, and the grey one for the left. If you’ve got the foam ear tips fitted, pinch it and gently twist it into your ear. You want the cable pointing upwards. From there simply guide the memory wire over your ear to secure it. You can wear the rest of the cable down your back and have it come around the front under your arm, or have it run down your neck and then over your front at the shoulder.

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