Sennheiser IE800S – Fireflies in the Midnight Sky


The IE800S possesses a spacious sig with strong emphases on cleanliness, detail retrieval and refinement. Instruments sound compact, snappy and clear, set against a holographic, well-layered and precise stage. In addition, the earphone positions its instruments neutrally on the stage – neither too intimate, nor too distant from the listener – with heaps of air and space between them. Because of this, its soundscape constantly possesses an open, free, voluminous profile. But, the single-driver configuration preserves coherence and unity, so zero listening fatigue is provoked along the way.

The IE800S’s overall tone is neutral. There aren’t any obvious peaks aside from a hint of mid-treble glare. With tracks like Ariana Grande’s Imagine, the ‘s‘ notes may stand out. It’s not harsh per se, though it does get hot. But, aside from lemons like these, the IE800S possesses a mindful balance between smoothness and articulation. As mentioned, the IE800S’s instruments are compact and tight. This isn’t a signature for audiophiles who prefer warmer, mushier, more intimate-sounding monitors. But, they aren’t withdrawn either. Sufficient midrange presence generates the vibrance needed to complement the extremes – resulting in a dynamic monitor with an ear for detail that does not compromise coherence.


As expected from a dynamically-driven low-end, the IE800S’s bass possesses great physicality – doling out solid, meaty punches without having to overdo quantity. This is done through extension, which the IE800S excels at. The mid-bass may sit in line with the midrange and treble, but you can still feel the impact coming through clearly and unobtrusively. In that way, you get the best of both worlds. A downward slope from the mid- and upper-bass is what gives the IE800S its clean, black background. The sub-bass makes its presence known in hip-hop tracks like Royce da 5’9″‘s God Speed. In fact, the low-end’s darker tone meshes beautifully with the whole genre – clean and defined, yet visceral all the while.

For genres like jazz, I’d personally prefer a bit more warmth to the bass. Contra basses like the one on Michael Bublé’s rendition of Song For You may lack a bit of resonance. It isn’t the most musical or emotive low-end. Instead, it’s more matter-of-fact. But, where this benefits is in its delivery of texture and detail. Bass instruments are excellently resolved to the minutest of nuances, allowing the listener to analyse to their heart’s content. However, the low-end does not sound sterile or dry in the least, because of the aforementioned extension and impressive sub- to mid-bass balance, respectively. The dynamic driver exhibits outstanding authority over the low-end, resulting in marvellous headroom. So, this detail and energy is delivered effortlessly with zero bleed upstream, and with impact, physicality and verve to boot.


The IE800S’s midrange rides the line well between body and definition. It does have the common lower-midrange dip to maximise cleanliness as naturally as possible. But, the dip isn’t egregious, so instruments maintain enough integrity to sound realistic. Returning to Imagine, Ariana Grande’s crisp articulation is noticeably louder than her deeper, chestier overtones. But, the latter still come through with authority and resolution, so her voice never sounds thin or incomplete. The same goes for snare drums. The dominant sound is the snap and crackle of the drum, but enough body is retained to do lower-tuned snares justice too. This is because of a gorgeously-tuned 1-2kHz rise. It gives instruments this density, roundedness and heft that – when paired with the IEM’s uncoloured tone – strongly evokes pristine, refined neutrality.

This is further bolstered by the midrange’s technical performance. The IE800S maintains its excellent composure and resolution here. No matter how crowded arrangements get, the image remains stable and the black background still comes though. Instruments are clean and well-separated, but not clinically so. There’s a warmth to them that prevents any plasticity from settling in. When combined with the aforementioned resolution, it creates a presentation that’s both precise and organic. Sennheiser doesn’t really commit to the former nor the latter, but striking that in-between makes the IE800S a very versatile monitor. Those who prefer a more upfront, intimate presentation may prefer more energy around 3-4kHz. But, for 95% of my library, it’s a difficult midrange for me to fault – coherent, full-blooded and clean.


The top-end is where the IE800S is most energetic. Articulation, clarity and air are all emphasised via peaks along 6kHz and 10kHz. The former compensates for the upper-midrange dip by giving instruments a vibrant, punchy pop. Although they’re neutrally-positioned on the stage, they still project with liveliness and sheen. The 10kHz peak sharpens transients and gives every note a crisp leading edge. With most tracks, it pairs perfectly with the 1-2kHz rise, complementing that meatiness with clarity and definition. But, with others, there can be a bit of glare. An example is Pusha-T’s DAYTONA album, except for the track Infrared. So, it may inch towards bright at times, but it remains composed for the most part.

In terms of technique, the top-end performs just as skilfully as the rest of the ensemble. Marvellous extension gives the IE800S lots of headroom. This is what allows that black background to constantly come through in the loudest of mixes. And, this is also what keeps the bass authoritative and composed. Although the treble is prone to the aforementioned glare at times, those brighter notes never linger for too long, because of the top-end’s admirable speed. It isn’t as fast as the balanced-armatures or electrostats I’ve heard lately, but they’re fast enough to prevent any fatigue from setting in. Finally, the treble delivers spatially as well. The diagonals are well-defined, allowing panned percussion to have genuine depth. Stereo separation impresses too, solidifying the IE800S’s precise imaging and its immersive, holographic stage.

General Recommendations

The IE800S’s designated timbre allows its technical performance to take centre stage. But, the density it’s allowed to possess at the same time gives it versatility as well. Here are three qualities that best encapsulate the IE800S’s fortes:

Crisp, clean, clinical neutrality: The IE800S is exceptional at segregating instruments and giving each their own pocket of space. In addition, the line between instrument and space is extremely well-defined and crisp. It easily produces the giddying sensation of instruments popping out of nowhere all around you, whilst remaining refined at the same time.

Top-class separation and resolution: Thankfully, the IE800S doesn’t tighten its notes and push its top-end just to fake a perception of clarity. Its resolution comes from genuine extension, so all that detail is easy on the ear and comes with headroom. Unlike less-capable IEMs, the lower harmonics are resolved fully (and not abandoned) on the IE800S as well.

A balance between crispness and body: Despite the IE800S’s bias towards compactness and separation, it possesses a fair amount of meatiness too from a 1-2kHz rise. Instruments have density and integrity, so they sound fully-formed whilst being clean and crisp at the same time. So, the IE800S is ideal for those who crave detail without sacrificing structure.

However, that very same signature does accept several compromises in order to bolster its separation, cleanliness and clarity. If the three aspects below are what you’re looking for in your next in-ear monitor, the IE800S may not be for you:

Warmth, wetness or euphony: The IE800S is a mostly neutral monitor, but its timbre tends to lean more towards tightness. Instruments don’t necessarily bloom or radiate warmth. Rather, there’s an effort to limit that sort of wetness as much as possible. If you prefer your monitors sounding less stringent and more loose, the IE800S isn’t the best option for you.

An intimate vocal presentation: U-shaped is an apt term to describe the IE800S’s vocal positioning. Even though they’re well-resolved and fully-formed, they’re positioned further back on the stage. And, they’re smaller in size too. The IE800S definitely isn’t a monitor to relish your favourite vocalists on, unless clarity and air are very high on your list of priorities.

A smooth, relaxed or rolled-off top-end: The IE800S’s top-end is crisp, airy and articulate. Although it’s been refined to remove as many bright spots as possible, it can glare or bite with inherently hot recordings. The clarity it produces is integral to the earphone’s signature, so if a softer, mushier top-end is your cup-of-tea, the IE800S likely won’t be.





Church-boy by day and audio-obsessee by night, Daniel Lesmana’s world revolves around the rhythms and melodies we lovingly call: Music. When he’s not behind a console mixing live for a congregation of thousands, engineering records in a studio environment, or making noise behind a drum set, you’ll find him on his laptop analysing audio gear with fervor and glee. Now a specialist in custom IEMs, cables and full-sized headphones, he’s looking to bring his unique sensibilities - as both an enthusiast and a professional - into the reviewer’s space; a place where no man has gone before.


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