Sennheiser IE600 Review

Sennheiser IE600 Review

16 March 2022 0 By Petros Laskis

The sweet spot

Pros: + Very musical and engaging tuning
+ Best Sennheiser mids after the HD650
+ Easy listening non fatiguing sound
+ Natural timbre
+ Great bass extension with excellent technicalities
+ Sharp imaging
+ Very comfortable
+ Small and lightweight
+ Good passive noise attenuation
+ Balanced and unbalanced cable of good quality
+ Excellent build quality
+ Scratch resistant shells
+ Nice carrying case

Cons: – Slightly lacking in dynamics
– Not too visceral
– Intimate soundstage
– Mild sibilance on “T” and “S” consonants


The Sennheiser IE600 was loaned to me by their Greek distributor for local reviewing purposes but I have decided to share brief impressions at Headfi.

The IE600 is the new, single dynamic driver iem from Sennheiser which is positioned between the flagship IE900 and the entry level IE300.
The selling price is €700 and is available from all authorized retailers.


Technical highlights

Resilient AMLOY-ZR01 amorphous metal housing, 3D-printed in Germany.
Direct, neutral tuning with fast, accurate bass.
Select 7 mm TrueResponse transducers optimized to achieve the lowest possible distortion.
Exceptionally neutral sound thanks to dual resonator chambers D2CA.
Gold-plated Fidelity (+) MMCX connectors for reliable connections.
Choice of para-aramid reinforced cables (3.5 mm, 4.4 mm).
Adjustable ear hooks and choice of ear tip adapters.
Frequency response: 4 Hz – 46.5 kHz
0.06% THD (1 kHz, 94 dB)
Impedance: 18 ohms

Full technical breakdown is available here.

sennheiser-ie-600-hifi-earphones-hifigo-520322_700x700 (1).jpg

Build quality and appearance

The IE600 is made from zirconium alloy which is manufactured by Heraeus Amloy Technologies.
It has triple the hardness and flexural strength of high-performance steel. Shock-frozen during manufacturing, amorphous metals never have a chance to form a crystalline structure like conventional metals.
The result is a lustrous, satiny surface that is extraordinarily resistant against corrosion and scratches.
The IE 600 housing is fabricated using metal-powder-based 3D printing that can create any shape imaginable within tight tolerances. Chambers and channels form as part of this additive manufacturing process with no milling required.
However, cost does limit the potential applications of this new material. One of the only places you’ll find it — besides ultra-high-end products like the IE 600 — is in the drilling head of a NASA Mars Rover where extraordinary resilience in extreme conditions is required.


The appearance is the same as with the IE900 but instead of the shiny and polished surface this time the finish is more dull and less luxurious.
I slightly prefer the IE900 appearance but still this is a discrete and beautiful looking earphone that gets vanished into the ear.
Build quality and finish are excellent while the IE600 seems to be very durable and scratch resistant, much more than its elder brother.


Fit and isolation

The IE600 is featherweight and with very small size, it is a real “in ear monitor” and a nice contrast to the bulky multi driver earphones that are flooding the market.
The shells are tiny and as such they vanish inside the ear, offering a tight and ultra comfortable fit suitable for extended listening sessions without causing ear fatigue and excessive sweating.
If there is one issue worth mentioning is that due to the shorter length and diameter of the nozzle, the IE600 must be pushed deeper into the ear canal, so the user might need a larger size of eartips than the usual and the largest size of the provided ones might not be enough.
Tip selection is crucial regarding noise attenuation and bass response, the memory foam eartips worked better for me and after getting the right fit the IE600 proved to be very effective in blocking outside the environmental noise.


Cable and accessories

The IE600 features gold-plated MMCX(+) connectors that are recessed in the housing for greater stability and guidance.
This type of MMCX connector is slightly different from the normal and finding an aftermarket cable is not so easy.
Two para-aramid reinforced cables are included, unbalanced 3.5mm and balanced 4.4mm.
There is also a 2.5 mm cable that is sold separately and not included as it is with the IE900.
Flexible, adjustable ear hooks further enhance the long-lasting comfort.
I know that a lot of people were complaining about the IE900 cables but honestly I think that they are of good quality, quite flexible and with low microphonic noise so I wouldn’t bother with aftermarket cables.


Two different styles of earbud tips — silicone and memory foam — are provided in three sizes to establish a comfortable seal in any ear.
A Premium carry case is also included along with a cable clip and a cleaning tool.


Listening impressions

As per usual practice I left the IE600 to burn for about 150 hours without monitoring the progress.
The listening tests were done with the FiiO M17, FiiO M11 Plus LTD and iBasso DX240 with the AMP8 MK2 module.


The overall tuning of the IE600 is utterly natural, not neutral and very balanced, it is pretty much one of the best tuned earphones that I have ever tested, almost perfect.
The sound is good, very good, musical, engaging, fun and enjoyable without venturing into tuning extremities.
This is a safe tuning that is suitable for all kinds of music, from electronic music to classical and jazz.
It is a likable presentation without any faults and most users will probably find it to their liking except the ones who prefer purposely mannered tunings.

The bass is just slightly boosted above the reference point with great extension to the lowest of the notes.
It never becomes too much and acoustic instruments like double basses and organ sound with the correct pitch while the IE600 is equally great with synthesized bass.
There is no bleeding whatsoever into the mids and the mid-bass is perfectly pitched without any unnecessary emphasis or coloring, at the same time the IE600 should be considered warm enough in a balanced manner.
The presentation is quite full but not so visceral and weighty yet at the same time it shouldn’t be considered as lean, it sits somewhere in the middle.
Technical presentation is truly excellent, at least for the category.
The bass is tight, fast and well controlled with natural recovery and great layering while it is clear and resolving.
Dynamics are good and lifelike but the IE600 doesn’t have the physical impact of other single dynamic driver earphones with larger drivers like the FiiO FD7.
Still the overall result is pretty satisfying and substantial both with natural percussion instruments and electronic tunes.

The mid range is, well, perfect, the tuning is wholly engaging, voices and instruments are rendered with the most convincing timbre with plenty of harmonic saturation.
The sound is weighty, full bodied and rounded with excellent presence and the most fine articulation, airy, soft and pleasant without any given harshness or edginess.
Natural sounding with just the needed amount of sweetness, warmth and wetness, the perfect combination of all the right ingredients that make for a highly addictive musical experience.
It is a pleasure to listen to all kinds of voices or vent instruments like solo oboe, clarinet or some blazing horns.
The IE600 was good with everything I tested but I thoroughly enjoyed it with Mozart’s Gran Partita for twelve wind instruments and a double bass.


These are HD650 – like mids, the closest tuning to the all time classic but this time with augmented technical prowess, more clarity between the lines, airer and more defined presentation.
Old time users of the venerable HD650 are going to love the IE600 this is the first Sennheiser creation that should be considered as the true successor to it, although in an iem form factor.

Thus said, there is a mild sibilance, it is not that the IE600 is inducing it in an artificial way but it is highlighting it when it is present in the recording.
“T” consonant gets a little pronounced and “S” even more, especially when listening to choral works like the following recording.


Treble has a very safe tuning, smooth, controlled and absent of any alarming peaks.
At the same time the IE600 is pretty resolving, with good clarity, adequate extension and enough energy to sound lively and not dull or boring.
Again pleasing and natural to the ear, treble sensitive users are going to love it while it gets pretty satisfying and detailed to cater for the rest.
Only the treble loving crowd and detail junkies will not remain satisfied and they will probably seek for something more detailed, analytical and brighter than the IE600.

Soundstage is mildly wide and spacious but not so holographic or layered.
Positioning is very accurate, with nice separation between the instruments but the whole presentation is more into the head, intimate and rather shrunk than glorious and expanded.


Brief comparisons

The IEx00 family
(from memory)

The IE600 is the sweet spot between the IE300 (review) and the IE900 (review) regarding both the tuning and the technicalities.

The IE300 is the least technically capable of the three.
Not so resolving, with lesser clarity, bass is not so controlled and layered, not as tight and it gets more bloomy – bleeding while generally speaking it is not as refined and articulated as its brothers.
Bass on the IE300 is more pronounced, with a touch of mid-bass emphasis while the mids are considerably more recessed, not as natural sounding and engaging while treble gets a fair amount of boost, here and there, giving a brighter and sharper tuning.
The IE300 is fuller sounding with more meaty sound, more fun, but thicker and slower with less natural timbre, not as precise and sometimes a little bright – piercing.

On the other hand the IE900 is technically superior, everything is on a higher level, from bass control, to layering, articulation, extension, detail retrieval, imaging, far better clarity, well you name it and the IE900 does it better.
Better dynamic contrast, more impactful with a grander and more holographic soundstage, out of the head projection with laser like positioning and a much finer articulation, the IE900 is the undisputed High End King.
Tuning is also slightly different, bass is more visceral and full bodied while retaining top class technicalities.
Mid range is fairly recessed, making it to sound more distant and neutral, not as engaging – warm while treble gets a mild emphasis which enhances detail retrieval and clarity, the IE900 is much more resolving and extended but at the same time it can be a little more bright sounding than the IE600.

Three different offerings from Sennheiser with diverse sound profiles and gradually increasing technicalities that naturally scale with the asking price.

Vs the FiiO FD7 ($600)
(side by side comparison)

FiiO FD7 (review) is another excellent single dynamic driver iem with a slightly different form factor, better accessories, tuning tubes and an excellent modular cable.

Assuming that you don’t care about physical appearance, fit, comfort and accessories, let’s talk about sound.

With the balanced sound tubes fitted to the FD7, the overall tuning between it and the IE600 is quite close.
Frequency response graphs might suggest otherwise but actually the bass extension is on the same level for both with the FD7 reaching as low as the IE600 while at the same time it is a touch more neutrally tuned without any mid-bass emphasis or bleeding on the mids.
Then the FD7 goes a different path with a bolder, fuller and considerably more visceral presentation, the larger driver is moving more air so dynamic behavior has greater impact while at the same time exhibiting top notch technicalities.
Mid range is so closely tuned between the two and although the FD7 is just a tiny bit more recessed the end result is equally full bodied, slightly warm and sweet with natural timbre and the same level of engagement.
Thus said the IE600 is more mid – centric, more pleasing and addicting in this particular area and as such it will appeal better to people who love their HD650 and are searching for something similar in an iem form factor.
Then there is an emphasis on the presence area, resulting in a more brilliant and resolving presentation from the FD7, with greater extension, more air between the lines, increased clarity and a surplus of energy but without sounding bright or fatiguing.
A key difference is on the soundstaging abilities between the two earphones.
Whether the IE600 is more intimate and into the listener’s head, the FD7 reaches outside the head, projecting the soundstage in front of the listener.
The FD7 is grander scale, has better holography and extended width, there is more space around the instruments
with the same positioning accuracy while ambience is communicated in a more convincing manner.


Don’t ask which one is better, because both are great and ideally you should audition both in order to choose unless you are an HD650 fan, then you should blindly purchase the IE600.

In the end

The IE600 is the sweet spot of the Sennheiser IEx00 family, sitting in the middle between the IE300 and the flagship IE900.
With one of the best tuned mids after the venerable HD650, balanced and natural, with excellent technicalities and a thoroughly musical, easy listening character, this is an earphone suitable for a blindfolded purchase, you just can’t go wrong with it whatever are your listening habits.

Test playlist

Copyright – Laskis Petros 2022.