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Earsonics EM4 Custom IEM Review: Front & Center

EarSonics EM4 Custom In-Ear Monitor


Long ago, before my first custom IEM, I found Earsonics and was intrigued by the SM3, so I bought it. It turned out I hated them at first and was sorry I spent $400 on something I didn’t think I could return.  After about two weeks time my opinion took a 180 and I realized I had found my favorite universal IEM, which outperformed the other IEMs I owned.  Since I liked the EM3 so much I sold my collection of high priced universal IEMs except the SM3 and got the EM3 Pro.


While the EM3 Pro is an upgrade to the SM3, I wasn’t overly impressed with it.  Even though it was technically and musically better, it missed some of the magic of the SM3 even though it had more bass capability and the best depth/forward projection ability of any custom IEM I have heard.  Earsonics listened to what the audiophiles were saying and developed the EM4, which was designed for audiophiles.  Shortly after the release of the EM4, the EM6 was announced which is tuned for the stage musician and has dual midrange and treble drivers.  On to the review.


The summary review of the EM4 and all other custom IEMs I have reviewed along with links to full reviews can be found here.


How to Order, Warranty, Options

Order can be placed on the website simply by putting an item into the cart and then creating an account to check out.


Options: Cord – clear, black; faceplate color; laser printing + 30 EUR; shell color



Four balanced armatures in a three way configuration using a dual bass driver and a TWFK for the mids and treble with dual bores.  The shell is filled with acrylic making it solid through and through.  The connector sockets are recessed.

Sensitivity: 124 dB/mW

Frequency response : 10 Hz -20 kHz

Impédance: 59 ohms


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Plastic carrying case and cleaning tool.  The case has a foam insert which includes a place for the cable and shells plus the cleaning tool.  While the case isn’t as durable as an Otter Box or Pelican case, it should suffice for normal use.  Your name is inscribed in the top of the case, however it isn’t quite as classy as other product cases.


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Standard custom IEM cable, black.  The cable performs the same as the standard Westone and JHA cables.  A silver cable is also available; however the silver cables oxidize green over time.  The cable fits perfectly into the recessed socket.




Durability/Build Quality

The solid acrylic shells are rock solid.  Build quality is as good as the extremely durable EM3 Pro.  Because the socket is recessed, the cable is very secure.  The cable is typical for custom IEMs, so durability should be the same, but since they are detachable the durability isn’t really an issue.  The shell is acrylic with an acrylic fill, and within that acrylic fill three are bubbles which can be seen in the pictures and in person, however the face plate looks good and the bubbles don’t really take away from the beauty of the EM4.  Earsonics provides a one year warranty on the shells.



Solid acrylic isolates quite well and better than the standard hollow acrylic shell, but does not offer quite as much isolation as silicone shelled custom IEMs.



The EM4 received 100+ hours of burn in as is customary before I do my serious listening.  You can read about my technique here.  My sound review is based off comparing with the EM3 Pro, JH16, SA-43, SE 5-way, NT-6, LS8, T1 Live!.



Bass: Using two large balanced armature drivers, the EM4 doesn’t lack in bass depth, power, or punch, and with enhancement, the sub-bass reverb is superb.  The enhancement is almost as substantial as the JH16 , but different due to more emphasis on the sub-bass region and a thicker presentation.  Combining the enhancement to the sub-bass, the texturing and detail level falls a bit behind the competition, but it is still better than most lower cost CIEMs and universals that I have.  Depth is very good with a slight roll off starting at 28 Hz, but notes still have substantial power at 20 Hz and I can hear/sense bass down to 17 Hz.  Bass speed isn’t the quickest, but it is still fast enough to keep up with fast drum sequences such as in speed metal and Japanese drums as well as fast electronic music, however the natural drum notes do have extra emphasis.


Warmth is present, but not to the extent of the EM3 Pro, retaining most of its richness and lushness, but not taking away from the clarity.  Thin is a word that never comes to mind with the EM4 due to the bass performance, which is overall very good.  While the bass is always powerful and has amazing capabilities, it is not overbearing and the liquid presentation makes it enjoyable.


Midrange: With the focus of the presentation centering around the midrange, the EM4 immerses you in the presentation with exceptional imaging, fluid notes, and detail galore.  Vocals are especially sweet, musical, and have a live feeling that is up close and personal.  In comparison with the other CIEMs I currently own, performance in the midrange is only bested by the more expensive 5-way, but not by too much, and the presentations are different.

Moving to the upper midrange area, the frequency response has a small dip that results in some instruments sounding a bit further back than they do with other CIEMs in the price range, which can lead to the EM4 sounding tonally off in direct comparison.  However, vocals always sounded realistic which in contrast can lead to other CIEMs sounding like the vocals are tonally off, so there is a tradeoff.


Treble: Bright, but oh so liquid, the EM4 has it all.  Treble that will please those that want more from their IEM, but don’t want harsh treble.  The EM4 treble is very forgiving, but at the expense of a slight amount of detail, and as the recording quality decreases, the resolution of the reproduction by the EM4 does also.  However, the note decay is longer than typical giving a very full treble response and a liquid, enjoyable, and rich experience.



The EM4 is different from anything else I have heard, but it reminds me of the SM3 before I moved into the world of custom IEMs.  The EM4 tries to be so many things, and it succeeds.  For example, there is a large space that is immersive, cohesive, and coherent, but at the same time the midrange is forward and up front, so you get the air plus the personal vocal performance.  The notes are fast with plenty of speed, but there is a warmth and fluidness to them that is very nice, and the richness of the presentation doesn’t have an impact on the clarity like the EM3 Pro or SM3.  Bass is enhanced and can really recreate the visceral impact of sub-bass, but when the bass in a track is subtle, the EM4 pulls back also.


The EM4 images well within its expansive soundstage, and when combined with the liquid presentation, becomes immersive.  In a way the presentation reminds me of the SE535, with a forward midrange and enhanced bass, but the integration and technical performance is so much better I feel bad mentioning them in the same sentence.  The upper midrange dip can lead to the impression of a depth within the presentation, and when combined with the treble, there is space added to the depth. Music quality is important as poorly mastered tracks don’t sound harsh or offensive, but do cause a reduction in detail and sound a bit smeared, leading to a very different and un-engaging sound from the EM4.  All in all, the EM4 presentation is very good and different than anything else out there.



EM3 Pro: Due to the sound signature of the EM3 Pro, I decided to do this comparison using the Whiplash TWag cable with the EM3 Pro to add some clarity.  First, these are brothers in that they have some similarities in the sound signature with a thick, warm, and rich presentation that has enhanced bass, but the EM4 got the better genetics!  However, at the same time the EM4 is brighter, although the EM3 Pro has a more mid-centric presentation.  Even with the cable advantage the EM4 beats the EM3 in clarity, space, and detail.  The EM4 is more spacious than the EM3 Pro overall, however the EM4 doesn’t have quite the depth that the EM3 Pro has with certain recordings, but most recordings don’t depth beyond the EM4 headstage.  Essentially, the EM4 has a more traditional soundstage presentation while the EM3 Pro is relatively unique.  Transparency of the EM4 is better than that of the EM3 Pro as the thickness of the EM3 Pro puts a veil over the sound while the mid-centric sound brings too much focus on the midrange, taking away from the immersion of the EM4.


While the EM3 Pro bass can be punchy with a large quantity, the depth just isn’t there compared with the EM4, and what is there isn’t as controlled or as detailed as the EM4.  The EM3 Pro is a bit warmer than the EM4, however due to the control of the bass, this warmth leads to a veil while there is no warmth induced veil with the EM4.  Midrange presentation is different as the EM3 Pro is mid-centric in comparison with the mid-forward EM4 and the levels of clarity and imaging are significantly different.  Vocals are rich with both but sound more tonally correct with the EM4 as the EM3 Pro has a larger dip in the upper midrange.  EM4 treble has much better sparkle and extension and while the EM3 Pro doesn’t lack treble or extension, the quality and technical capability lag the EM4.


The EM4 is what I was hoping the EM3 Pro would have been after the SM3 won me over.  While the EM3 Pro does one thing better than the EM4, depth of soundstage with select recordings, the EM4 offers better technical performance in every other way while still offering a similar sound signature.  Fans of a warmer sound can still get good sound from the EM3 Pro, but I can see the EM4 being preferred by most.


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JH16: The JH16 has a brighter presentation compared with the warmer, airier presentation of the EM4.  The EM4 is closer in presentation to the JH16 than the EM3 Pro, but is still an Earsonics product.  Note thickness isn’t too far off between the two, but the EM4 does have a thicker, more reverberant note on average.  The attack of the JH16 is quicker than that of the EM4, but not by much, giving a small speed edge to the JH16.  On the flip side, the EM4 has a bit more note sustainment than the JH16.  Spatially the EM4 offers more depth of presentation with just a bit less width, resulting in better soundstage proportions.  While the EM4 has a mid-forward presentation, the JH16 is overall more forward.  Dynamics of both are similar, however due to the quicker attack of the JH16, it can sound punchier and have more apparent dynamics.  Clarity levels aren’t too far from each other, but the JH16 does have more clarity due to the brighter presentation, although instrument detail levels are very similar while the EM4 exhibits more overall resolution and definition of space.


Overall the EM4 has a deeper tone and a bit more rumble but a bit less control and texturing than the JH16, which puts more emphasis on the upper bass region.  Overall both are very capable in the bass region, but the EM4 surprisingly rumbles more in the sub-bass region with most tracks, especially hip-hop and pop.  But with bass light songs the JH16 exaggerates the bass more so than the EM4.  In Earsonics fashion the EM4 is warmer than the JH16, with a richer presentation, however the differences are not huge.  The EM4 vocal region of the midrange is a bit more forward while the upper midrange of the JH16 is a good deal more forward than the EM4 resulting in different soundstage presentations depending on the songs and instruments.  Vocals sound realistic and nuances are well articulated with both, however the EM4 conveys ambiance of the performance that the JH16 misses.  The upper midrange peak of the JH16 leads to much stronger Ss and emphasis on details in that region, but the EM4 sounds more airy with a smoother yet more detailed treble that extends further.  The emphasis of the upper midrange through the treble is the most contrasting part of the spectrum with these two, with the JH16 having more emphasis in the upper mids in comparison with the treble and vice versa with the EM4.


These two perform fairly close technically, however they have different enough sound signatures to fit similar but different preferences.  The EM4 has a warmer, richer presentation that is more laid back, airy, and 3D while the JH16 is punchier, especially in the upper bass region with a very bright upper midrange/lower treble that brings certain details to you.  While both do vocals quite well, the EM4 adds a bit of ambiance to the presentation.


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LS8: Tonal presentation between these two is different as EM4 is warmer vs. the brighter LS8 changing the way vocals sound and changing instrument placement with higher tones.  The majority of the time the LS8 has a more intimate presentation vs. the laid back presentation of the EM4 and the EM4 presents a larger space both in width and in depth, but at times due to the mid-forward presentation of the EM4, some recordings sound more spacious with the LS8.  Depth is pretty close most of the time except with very spacious tracks, where the EM4 can project further.  Clarity levels are similar between the two, however the LS8 does offer a slightly clearer presentation due to the upper midrange peak.


Overall detail levels are similar between the two, but the bass region of the LS8 is more textured and detailed while the midrange detail levels are similar, but imaging is better with the EM4, creating more layering and depth.  The LS8 has more treble detail and instruments across the spectrum do display more detail while the EM4 gives a better sense of the overall space and presentation.  While the LS8 is anything but slow, possessing great speed, the EM4 can keep up for the most part; however with very fast bass line the EM4 does sound a bit slower.  Both give punchy presentations with similar transparency and dynamics.


While the LS8 doesn’t lack in the warmth or deep bass area, the EM4 conveys more power and warmth.  This is in part due to the higher levels of upper mids with the LS8 and part due to more deep bass output from the EM4.  The LS8 is no slouch though and except with the most demanding of tracks the LS8 does keep up and can out punch the EM4, but not out rumble.  Texturing is excellent with both, but as mentioned, the LS8 has the edge.  With different tonalities in the midrange, the EM4 conveys more emotion, ambiance, and detail in vocals while the LS8 articulates instruments with more detail and precision.  The presentation with the LS8 is intimate, as stated above, compared with the EM4.  The LS8 possesses a very liquid and smooth treble and the EM4 follows suit, however with a different tonality due to the upper midrange peak that carries over into the treble region.  As with the midrange, the LS8 is more detailed while the EM4 is a bit more musical.  Both extend very similarly, however the LS8 does extend a bit further.


Both offer warmth, some bass enhancement, liquid presentations, and great treble extension, however they do have different strengths.  The LS8 is better at focusing on the instruments and resolving all their details while the EM4 is more about the overall presentation and the vocals while having more depth to the presentation.  Both perform close technically.


SA-43: The first difference that is presented when A/Bing these two is in the midrange presentation as the EM4 is more mid-forward than the SA-43, even with the presence switch on.  There are also tonal differences as the EM4 is brighter and warmer.   The SA-43 has more width and spaciousness than the EM4, but the EM4 isn’t far behind in headstage, although the soundstage appears smaller due to the more forward presentation.  The EM4 is more enveloping and has a slight coherence advantage with presentations that should be more mid-forward while the SA-43 sound more natural and realistic with laid back, spacious presentations.  Transparency is close, but the SA-43 edges out the EM4 due to the more natural, laid back sound.  With more brightness, the EM4 has a slight bit more clarity and focus to the presentation than the SA-43.  Notes are a bit thicker with the EM4 but it also has a slight speed advantage over the SA-43.  Detail levels and dynamics are also slightly better with the EM4 than the SA-43. Both are smooth, but the EM4 is more fluid.


The deep bass of the EM4 has more reverb, power, and depth than the SA-43 and doesn’t have the slight roll off that the SA-43 has.  Overall the EM4 is more punchy and warmer through the bass region while texturing is a bit better with the SA-43.  The midrange of both excel, but in different ways, with the EM4 making vocals sound magic while the SA-43 gives the entire presentation more focus, even with the presence switch on.  With the switch off the SA-43 sounds a bit hollow in comparison.  There is more emphasis in the upper mids of the SA-43, which flip-flops to more treble emphasis with the EM4.  Quality is similar, but the EM4 extends much further than the SA-43.


The SA-43 and EM4 are close in technical performance, however they both have their strengths.  The EM4 is great for those that want a mid-forward presentation, and if you were to listen to the SA-43 with the bass and presence switches on all the time the EM4 may be preferred.  But overall the SA-43 has a more natural presentation vs. the more exciting EM4.  The SA-43 wins for versatility and offers a laid back plus mid-forward presentation that works well with more genres of music.  The EM4 is much easier to drive, however, so the decision between the two should take your source and music collection into consideration.


UERM: The UERM is a reference monitor sound while the EM4 is Earsonics tuning for the audiophile crowd  while retaining the warm and liquid Earsonics sound signature, with added clarity.  The UERM has a more spacious sound that is laid back through the midrange, but more forward in the treble than the EM4.  The EM4 sounds more musical ,liquid, and transparent as well as more dynamic and exciting in comparison with the analytical sound of the UERM.  Clarity of the EM4 is about on par with the UERM, however it is track dependent as either can offer better clarity depending on the track, but the difference isn’t huge.


While the overall detail levels are similar, the EM4 has better resolution of the midrange while the UERM presents more detail in the treble and better texturing, albeit less ability to sustain notes.  The UERM has the advantage of more depth to a presentation and images well, however the EM4 images better, with more precision, especially throughout the midrange, making the UERM sound a little flat in comparison on most recordings.  The EM4 has a more coherent presentation in comparison, making the UERM sound slightly disjointed in direct comparison.


While the EM4 is warmer with more bass emphasis and ability, the enhancement and warmth differences aren’t large except with bass heavy songs such as electronic and hip-hop/some pop.  With those genres, the EM4 can really belt out the bass while the UERM falls behind, but conversely the UERM does have better bass texturing.   Bass extension is superior with the UERM.  The EM4 shines in the midrange presentation, which is more forward with better spatial recreation (except in rare occasions where there is exceptional depth to the recording), and more coherency leading to better realism and transparency.  The bump in the upper mids of the UERM can give vocals a higher tone than the more natural and warmer sounding EM4.  Treble is very different between the two with the UERM having more prominent and forward treble that is more detailed yet more analytical and harsh.  The EM4 is more forgiving of poorly recorded material, as it reduces the detail level vs. prominently recreating the issues like the UERM.  While both have similar frequencies where the treble starts to roll off, the EM4 extends a good deal further past that point and the UERM drops rapidly.


With very different presentations and design philosophies, they don’t share much other than high technical capability.  If you want a musical, coherent, involving, punchy, rich, warm yet precise and clear presentation that has a mid-focused sound, the EM4 is the one.  If you want a more analytical sound with a treble focus and excellent 3D qualities for mastering or even musical enjoyment, the UERM is a good choice.




SE 5-way: The 5-way has set a new standard for me in many ways; how competitive is the EM4?  The sound signatures are different with the EM4 having more emphasis on the bass as well as a little warmer presentation and less treble.  Both have a mid-forwardness to them, but it is different due to the differences in placement and the upper mids.  Resolution/detail of the 5-way is superior as little nuances are recreated within space that aren’t there with the EM4, except in the midrange to an extent.  The 5-way changes much more with each track and will sound thicker or thinner, clearer or less clear, etc. based on the song, but overall the 5-way has better attack/decay ability.  The EM4 is more forgiving of poor tracks, but reduces the detail level to do so.  Speed is similar and while the EM4 can sound more dynamic in general, the 5-way is more dynamic when the song really calls for it.  Soundstage space isn’t too far off, but in certain songs the 5-way can really pull ahead, as can imaging.  Transparency of the 5-way can be much higher, again depending on the track.


The EM4 has enhanced bass, but the 5-way can output the same amount of bass or more depending on the track; texturing and punch are also better with the 5-way.  However, the EM4 isn’t a slouch in the amount of bass it can output, keeping up with the 5-way in quantity.  Tonal comparisons are tough since the 5-way changes more than the EM4 with each track.  The midrange, which is the strength of the EM4, does not sound quite as natural as the 5-way midrange and is a bit more liquid.  Vocals are presented differently due to the greater midrange focus, but also the depth of presentation isn’t quite as good as the 5-way.  However the vocals have more excitement in them in general and technically on par.  The upper midrange of the 5-way is more prominent giving a fuller midrange experience.  The 5-way treble is more prominent, smooth, and detailed with a bit better extension, but the EM4 treble is more liquid.


Both are made in Europe and the price difference isn’t all that large, so these two can be considered competitors.  Aside from a solid acrylic shell vs. a silicone shell, the differences lie in the little things.  The EM4 has a warmer, richer presentation that is bass heavy and tuned for excitement while the 5-way is more airy sounding with a brighter presentation that is still very bass capable, even if it doesn’t flex its muscles all the time.  You will get more variation from track to track with the 5-way than the EM4, so depending on the track, you might get a fairly different in comparison.  Resolution of the 5-way is superior, however the vocal region of the EM4 is special and on par.




SM3 v1: Saying the EM4 is an upgrade to the SM3 is an understatement as the EM4 is more dynamic, punchy, clear, and has a larger sound stage.  While they both have mid-focused presentations and are both liquid, the treble is significantly increased as well as the amount of bass with the EM4.  The SM3 sounds fairly dull and lacking life compared with the EM4, not to mention somewhat veiled and on the dark side.  The SM3 does nothing better than the EM4, giving the EM4 a decisive knockout punch.

Volume performance: The EM4 has very good volume performance from the low end through what I consider loud.  The bass drivers kick in at a relatively low level, but a bit of power is needed to really achieve what the EM4 can do in the bass region.  The sound signature doesn’t change from that point on up to very loud.


Sound Summary:

With a warm, liquid, and clear presentation that is mid-forward, the EM4 is an excellent performer technically.  Add the enhanced, powerful bass, and a rich presentation that is bright, punchy, and dynamic, the EM4 exudes excitement.  Vocals excel and envelop with the EM4, but the bass and treble are in no way lacking.  The cohesion of the presentation is very good, giving the ‘in your face’ sound a transparent and engulfing experience.  Detail levels are in line with the other CIEMs in the price range, although not the best, but the EM4 does offer a warmer, more liquid presentation than the rest.  Spatially the EM4 is very competitive with other CIEMs in the price range with good imaging, separation, and placement.  While there is very good depth to the soundstage, it can’t project quite as far as the EM3 Pro, but is a good deal wider.


During my review I often found myself having to refocus myself on the presentation vs. the music as the EM4 offers excellent transparency and a great balance of speed, clarity, and warmth,  all at the same time.  In direct comparison with some of my other CIEMs, the upper midrange didn’t seem as tonally accurate, however this wasn’t an issue when listening without comparisons.  And the vocals never had this problem, often making the vocals of others sound off or flat and less involving.


Source matching

Portable Sources, DAPs

Clip+: The Clip+ is an acceptable source with the EM4 for the ultra portable on the go size.  This combination doesn’t leave me really wanting much more unless I have just been listening to a better source recently.  I didn’t care for the EM3 Pro with the Clip+, but that is not the case with the EM4 as the brighter presentation and clarity plays well with the Clip+.  Not the best performance, but for the size and price there are no complaints.  6/10

iPhone 3G: The EM4 plays well from the 3G.  The dynamics, resolution, and space aren’t quite what they are from a higher end source, but the overall presentation is still quite acceptable, especially for on the go.  5/10

iPhone 4S: Performs similar to the 3G, although the bass has slightly less depth and the dynamics take a miniscule step down from the 3G.  The presentation is overall a bit more spacious than the Clip+ and while there is less bass presence, the dynamics are a bit better.  The 3G is overall better match but the differences are very minimal and not worth even half a point.  5/10

iPad 2: The iPad has more presentation depth compared with the iPhone 4S, resulting in more apparent detail and a slightly more dynamic sound.  Speaking of depth, the iPad also has a bit more emphasis on the deep bass.  Overall the iPad is a bit more enjoyable than the iPhone 4S, but the differences aren’t huge.  Still, the iPad works well with the EM4 and is a good option for pairing with the EM4 if you want to take the simplistic approach.  5.5/10

RoCoo Power: While the RoCoo is an improvement in refinement and overall musicality compared with the iPhone and Clip+, and the hiss issue has been fixed, another issue has arisen: bass roll off.  Still, I would rather listen to the RoCoo vs. the iPhone or Clip with all but my bass heavy tracks. 5/10

801 (GAME Card): The 801 can be an amazing match with many CIEMs; the pairing with the EM4 is good, but not great.  The 801 is the best portable source I have heard with the EM4 (before owning the DX100) sans an amp, but the overall dynamics are a bit subdued and the transparency isn’t quite what I am used to with the 801 to an amp or the D1, or even the iPod to an amp. 7/10

DX100: Comparing the DX100 with the 801 for powering the EM4, you get a more dynamic presentation with better imaging and instrument separation and presentation depth.  While the 801 is smoother and organic sounding, the DX100 is more defined and involving due to the creation of a more realistic space and a cleaner overall sound, if even by just a bit. 8/10


Portable Sources, DAPs with Amps

Modded iPod -> Many of the amps over emphasized the treble with the EM4, taking away from the naturalness of the presentation.

Arrow 12HE: The Arrow is a smooth performer with the EM4, with a very spacious and natural sounding presentation.  The sound is a bit leaner than the others which sounds like there is a level of clarity added. Overall the Arrow does much right with this setup.  7/10

Neco V2: The Neco is a very affordable amp that pairs well with the EM4.  It is warmer and a bit less bright compared with the Arrow, giving a more mid-forward presentation.  The spaciousness is very nice.  The negative is the a slight channel imbalance at very low volumes. 6/10

uHA-120: The uHA give the EM4 a nice smoothness in comparison with the PS and SD, but loses out a bit in the space department to the SD.  However, the uHA is 3D and a decent performer that has a slight emphasis on the midrange. There is a slight channel imbalance at very low volumes.  6/10

Pico Slim: The Pico Slim performs well, but compared to some of the amps it doesn’t give the spaciousness in the presentation others such as the Stepdance and Cruise give.  There is a brightness, similar to the Cruise, but the Cruise has more weight and is smoother.  Clarity also seemed to take a small step down vs. the Stepdance.  Overall the sound isn’t bad, but a step down from the others.  5/10

Stepdance: The Stepdance matches very well with the iPod and EM4, giving great control and power to the EM4.  Spaciousness and detail levels are great and the 3D space is very good. 6/10

Cruise: There is a bit more resolution than the Stepdance, but the sound is brighter, bringing the upper midrange/treble forward a bit.  Music is punchy and the presentation has added depth and layering compared to the Stepdance, but there is low level hiss, which isn’t there with the others that I can hear between tracks. 6/10


801 -> Overall there is more bass presence than from the iPod with the same amps and less treble presence.  Since the line out is fixed, unlike on the iPod, the channel imbalance with some amps is worse.  Compared with the headphone out with the GAME card, the bass is more prominent with the amps, there is a bit more 3D space, and the whole presentation is more dynamic.  The sound is also a bit darker than with the amps.

Arrow 12HE: The Arrow just sounds right with the EM4, with space, air, bass control, and a nice smoothness.  The biggest knock is the resolution level is a bit lower than the other amps, which is noticeable because of the 801’s high resolution level.  The laid back presentation of the Arrow works well with the EM4, balancing and making the presentation very enjoyable and engaging. 9/10

Neco V2: Like with the iPod, the V2 pairs very well with the EM4 form the 801.  The sound is very controlled and overall the presentation is nice, but amps like the SD are slightly more 3D, however not more spacious, and there is a slight channel imbalance at low volumes (lowering the score). 7/10

uHA-120: Not quite the resolution of the Stepdance and a bit of grain in comparison, however the treble is slightly smoother.  The space is also a bit smaller with more midrange presence. There is a channel imbalance at low volumes (lowering the score). 7/10

Pico Slim: The Pico Slim sounds very 3D, but ever so slightly subdued compared with the other amps.  The bass isn’t quite as impactful, however the presentation is very smooth.  Spatially, the SD is a bit smaller overall and the sound takes more of a mid-forward presentation than the other amps. 7.5/10

Stepdance: While the Stepdance is beautiful in the lower end with the EM4, the treble is not quite as smooth as many of the other amps, so you get to pick your poison.  Otherwise the SD is very nice giving a great sense of 3D space to presentations.  8/10

Cruise: With great depth and space to the presentation, the Cruise pulls ahead, not to mention the exceptional dynamics.  The sound is on the brighter side, but is very smooth and velvety, with plenty of bass punch.  However, listening to quite tracks, there is audible hiss that isn’t there with the others, detracting from the overall great presentation. 7/10


Desktop Sources

HUD-MX1 (OPA1611): Coming from the 801 listening, the lower resolution, rougher presentation, and less spaciousness are apparent, but compared with the TTD V2 the MX1 has the upper hand.  First, the channel imbalance is minimal in comparison, about on par with the uHA amp.  While the TTD V2 does sound more natural and open, I can’t get by the other issues.  The quicker note of the MX1 (with the OPA1611) turn the EM4 more to the neutral side of things vs. warmer, which isn’t all that bad.  The smoothness though is where I am most disappointed in the MX1.  The overall performance is about on par with the RoCoo, but with more clarity and resolution, but not the same musicality, and with plenty of bass weight.  5.5/10

Uber Muzik TTD V2: The sound from the TTD V2 is great with the EM4 as it is punchy, liquid, and very musical, but the issues with the V2 prevent this from being a good match without using an amp between the V2 and EM4.  The high gain requires use within the very bottom of the volume range, where there is a channel imbalance, and the background is far from black, with a relatively high noise floor.  2/10

Anedio D1: The D1 adds some nice bass control to the EM4, brings out more detail than any other source, and gives a nice transparent response, the treble is a little more emphasized than I prefer.  Other than that, the pairing is very very good. 9/10


Source Summary: The EM4 performs very well from entry level DAPs such as the Clip+ and there are minimal improvements as you move up the listening chain.  Higher end DACs will add some additional space and detail to presentations while an amp will control the bass a bit better, but overall the gains aren’t huge.  There is no need to go all out with the source unless you really want to eke out every last bit of performance.





Tuned for the audiophile, the EM4 gives an impressive presentation, immersing you in the experience and bringing the performance right to you.  The mid-forward presentation puts vocals up close and personal while giving you great tonal quality and imaging with bass that is enhanced, powerful, and visceral and treble is extended and realistic.  Everything is presented in a very fluid way and thin is never a word that comes to mind with the EM4, but that doesn’t prevent a bright and very clear presentation.  Detail levels are very good, especially in the midrange, and with great transparency, the EM4 gets out of the way of your music.


The liquidity allows the EM4 to be very forgiving, but the side effect is a slight lowering of treble detail, and bass texturing is typically a bit lower than the competition, which is a tradeoff for the enhancement and capability.  In direct comparison with many others high end CIEMs, the EM4 has a bit of a dip in the upper midrange which can lead to the sound being slightly ‘off’ sounding at times compared with other top custom IEMs.  However, dynamics and speed are excellent leading to a presentation that is exciting, punchy and fast while being warm and immersive; an impressive combination.  The EM4 has a special sound that reminds me of the SM3 when I first heard it, but oh so much better in every way!


Overall, the EM4 gives a combination of speed and clarity with warmth and richness I have not heard elsewhere.



–       Bass capability and ability to rumble with sub-bass notes

–       Liquid, spacious midrange that makes vocals sound enveloping and engaging

–       Complete presentation from top to bottom that is cohesive



–       Bass isn’t the most textured

–       Slight dip in the upper midrange can lead to tonal issues in direct comparison with other top level custom IEMs



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Having a life-long love of high-quality audio and gadgets, average_joe got back in touch with his audiophile side after a hiatus caused by life. His focus became headphones and related gear as the size and price fit his life better than home audio. He believes the entire audio chain is important, and likes to continue to think past the headphone and on into the head, as he believes understanding the details of how we hear will lead to a better audio experience.


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