Hidition NT-6 Custom IEM Review: The Ultimate Reference?
Jan 7, 2012 at 3:28 AM Thread Starter Post #1 of 992


Headphoneus Supremus
Dec 5, 2008
[size=14.0pt]Hidition NT-6 Custom IEM Review: The Ultimate Reference?[/size]

[size=11pt]Hidition, located in Korea, has been making custom IEMs for quite some time but recently just revamped their lineup and website.  Their products are primarily sold through stores in Korea, but they are now selling internationally.  I contacted Hidition to find out more about the company and was able to talk with Seoung ByoungHa about the company and their new product lineup.  They were gracious enough to provide a sample for review and offered me choices based on sound signature.  I decided to go for the balanced sound, which turned out to be the NT-6 - a 6 driver 4-way design.  They have three other models including the NT-6 Pro that has 6 drivers in a 5-way configuration and has enhanced bass and treble, the NT-RM (Recording Master) which is a 3 driver bass enhanced model, and the NT-1, a single driver CIEM.  Part of my choice was a result of just finishing my UERM review and being curious how the balance sound offering would compare, and part due to many of my CIEMs in the price range having enhanced bass, such as the JH16 and LS8.[/size]
[size=11pt]Since Hidition is in Korea, I sent my impressions off via USPS Express international, and they arrived quickly.  I have to admit communication hasn't been the easiest as Soeung's primary language is Korean.  They were busy working on the relaunch of their site and products so there was a wait, but that is to be expected for my situation.  Soeung is a very nice person to work with in general. [/size]
A list of all the headphones I have reviewed can be found here, which includes scores and links to full reviews.
[size=13.0pt]How to Order, Warranty, Options[/size]
[size=11pt]The Hidition NT-6 cost 1,188,000 won plus VAT in Korea and $1200 internationally.  International ordering is done through the www.hidition.co.kr website by selecting English at the top right of the site, selecting your items, then selecting buy.  They can be paid via bank transfer or credit card.  [/size]
[size=11pt]While Hidition communicates in English, it is not their native language and added to the back and forth to get everything correct for my order; the new online system should help significantly with that.  It took several days to receive a response many times, but I did always get a response, and it could have been in part, due to all the changes going on within the company.  Hidition was very good about working with me and is taking the case and cable issues I have raised seriously; a very good sign about the company and their customer service.[/size]
[size=11pt]Options: Custom color: free; Provided artwork (1000 x 1000 dpi): left and right the same - $77, left and right different - $100; house design artwork - $59; Jewelry(cubic) - $97; abalone shell coating - $97; HIDITION LOGO DESIGN - free; Custom metal logo design - $120; ambient vent - $65; Cable: premium - $200[/size]

[size=11pt]International shipping : $30; $40 for shipping with insurance[/size]
[3/24/14]: It is recommended to take closed mouth impressions and send pictures of your impressions before shipping them.  Order instructions can be found here.
The NT-6 uses 6 balanced armature drivers in a 4-way configuration (3 crossover points) that utilizes 3 sound tubes in an acrylic shell with a detachable cable.  Three BAs are used for the bass, with a CI type BA and a DTEC (dual) providing a good amount of surface area.  The flush sockets are pin compatible with Westone and JHA cables.
The NT-6 includes a nice looking hard carrying case, a cleaning tool, a soft wipe cloth, instructions, and a frequency response chart in a nice box.  The case, while very nice with the Hidition logo and name imprint, is a little on the small side and not the easiest to get closed completely when the NT-6 wasn't positioned just right.
Note: the carrying case is too small for the shells of larger ears to fit properly, so Hidition is working on a new case.
Feb 20, 2012 Update: The new case arrived and it is larger, although it still looks the same.  The case is smaller than a typical case, but will fit my NT-6 with no issues, although it is a tight fit.
I have the upgraded cable, which is not your stock Westone/JHA style cable; instead, it is closer to a Beat Audio cable with molded ear hooks and heat shrink over the entire cable.  A Palic 3.5mm plug is used, which should be compatible with many iPhone cases, and the shell connectors are angled and on the larger side.  The cable does have some microphonics even though it is an over the ear design.  The cable is pin compatible with JHA and Westone products.
Note: I will be getting the standard cable with my NT-6 Pro.
Feb 20, 2012 Update: Upgraded cable (new build) vs. standard cable (pictured above with the new case).
I burned in both cables for about 100 hours and here my thoughts and A/B results:
The stock cable has slight microphonics while the new upgraded cable still has microphonics, however they have been reduced.  Not having the original cable however, I can't say by how much other than it is still very noticeable, but more tolerable to me.  I think this is due to the microphonics being much worse (not compared with the original upgrade cable, but in general) when the cable rubs against a solid surface vs. my clothing.  For example, against my clothes there is little microphonics, but against the arm of my chair or desk it is bad, and really bad when rubbing against the stock cable 
  I can't really tell much of a difference physically other than it may be a bit thinner.  The stock cable uses a very tight twist and has better ergonomics than the upgraded cable, however the stock cable isn't quite as flexible as a standard twisted custom IEM cable, but it does look much nicer.  
From a sound perspective the upgrade cable conveys more deep bass weight and increases the depth of the soundstage, which also improves imaging.  The NT-6 is still ultra detailed and clear with the stock cable, but the upgrade cable gives you a bit of extra refinement and bass.  This may improve with more burn in.  I will update at some point in the future.
[size=13.0pt]Durability/Build Quality[/size]
Not unlike my other acrylic shelled custom IEMs, build quality of the shell is not something that needs to be questioned as it is durable and well built.  The shell protrudes from the Concha a bit at the bottom, but looks fine when worn.  There is something in the shells, possibly acrylic drops, but with the green color I chose they are barely noticeable to the naked eye; you have to look closely to find them.  While the outside of the shells doesn't look perfect in the pictures, the issues shown are difficult to see with the naked eye and the shell si smooth to the touch.  The cable is very well constructed with heat shrink, aftermarket Palic 3.5mm plug, and large molded shell connectors.
Feb 20, 2012 Update: I sent my NT-6 back for a refit since the canals were a bit on the too large side and caused discomfort after 1+ hours of use (an issue with the impression material for my self impression).  Hidition kindly redid the shells and upgraded my artwork as can be seen below.  Build quality from a fit perspective is better than the original as the shells are more flush.  The cable joint also now protrudes a bit instead of being flush, offering some additional connector stability.
Isolation is listed as 26dB on the Hidition site and seems about average for the acrylic shelled custom IEMs I have such as the LS8, JH16, and aud-5X.
The NT-6 received 100+ hours of burn in as is customary before I do my serious listening.  You can read about my technique here.  For comparison I used the UERM, JH16, SA-43, SE 5-way, LS8, and EM3 Pro.
** NOTE ** Due to my perspective and comparisons with similarly priced custom IEMs, weaknesses are more apparent and unless you have the contrast, chances are you may not notice the weaknesses.
Upon my initial listen I was impressed by the NT-6, which isn't always the case when I first listen to custom IEMs.   I could immediately hear the high level of detail along with many of the other positive traits even before it was put into perspective through direct comparisons.
Bass: Most IEMs, custom or not, that I have heard that are neutral in the bass region have left something to be desired with many bass heavy tracks on my playlist, lacking in some way.  The NT-6 recreates bass in a flat manner all the way down, actually with an ever so slight bump in the very lowest registers, while providing detail, speed, texture, and the ability to sustain notes with proper reverberation when needed.  The bass is not unlike the CK10, but with more power, weight, and authority resulting in a more tactile and visceral feel in comparison with the CK10.  Compared with CIEMs in the price range, everything is bass enhanced except the UERM and SA-43 with the bass switch off, but both don't extend as deep or have the bass headroom, especially the UERM. 
The ability to recreate deep bass with great headroom allows the NT-6 to technically outperform all CIEMs I have heard except the SE 5-way.  I was surprised that the JH16 sounded fairly uncontrolled in comparison with bass heavy tracks, however the issue seemed to be due to the significant amount of added enhancement.  The UERM in comparison was a little slower and thicker in note and also had less headroom and deep bass. 
From a warmth perspective the NT-6 is slightly on the thinner side of neutral, although with warm masters the NT-6 has good warmth but won't recreate a rich presentation like the 5-way, LS8, or EM3 Pro.  For example, Queen - Forever sounds a little thinner and more detailed than I am used to hearing, but still has a musical quality with decent warmth.
Midrange: Class leading clarity and imaging often make CIEMs I thought sounded clear and precise sound a little fuzzy or imprecise in the midrange area.  The only CIEM that didn't have this issue was the 5-way which presents music in a thicker way, which has a different type of clarity than the brighter sounding clarity due to a better sense of overall depth, space, and definition.  However the NT6 frequency response sounds flatter throughout the midrange than that of the 5-way and everything else including the UERM.
As stated, imaging is superb in the vast majority of my tracks with everything placed correctly having great definition.  The midrange is placed in a fairly neutral position, but does adjust to an extent with each recording.  Details are dissected and served to you on a platter for easy consumption and overall resolution is excellent.  Both male and female vocals sound very tonally accurate as the NT-6 can make some other CIEMs that normally sound accurate seem a bit off. 
Treble: With great extension and a very even response that tapers up slowly, which brings the treble a little more forward, similar to the UERM, only technically better.  Notes aren't the thickest or smoothest, but there is a smoothness that is amazing when combined with the immense treble detail.  Extension is great and while it doesn't extend to quite the reaches of the 5-way and LS8, it does come close at 19KHz.  But, the smoothness of the frequency response is really something to behold bringing out the imperfections of other CIEMs I thought were great.  With poorly mastered or lower bitrate tracks the NT-6 will let you hear the faults, but not to the extent of the UERM while many CIEMs such as the 5-way, SA-43, and LS8 will smooth and hide faults in comparison. 
Presentation: Not quite analytical, not quite dry, the NT-6 recreates details in music with very high levels of precision and detail while still doing so in an enjoyable way.  As discussed above, the imaging and clarity are amazing as well as the headroom present.  Note presentation is on the leaner side resulting in speed and clarity that presents the detail to you in an upfront and easy to hear way.  While the presentation isn't too dry, it is not the most fun and musical presentation but excellent for analysis purposes.

The music recreation is done in a well proportioned soundstage with very good size, about on par with other near top performers such as the 5-way, but the larger space is dependent on the midrange presentation of the track.  While imaging is exceptional, the overall depth of the soundstage isn't quite as large as the EM3 Pro, SA-43, 5-way, and slightly smaller than the UERM but better than the LS8 and much better than the JH16.  This is the only part of the presentation of the NT-6 that I find technically inferior to multiple CIEMs.
Detail levels are top notch, offering detail equaling the 5-way and superior to the other CIEMs used for comparison while the overall resolution (ability to resolve black space) is second only to the 5-way.  Clarity and dynamics are also top notch and transparency is third behind the 5-way and SA-43.
UERM: Both were designed to have flat, reference sound, and they do, with many similar characteristics, but the UERM is more analytical in comparison to the more musical NT-6.  The UERM can really let my ears have it in the treble department when playing a not so well mastered track while the NT-6 will let you know the track is less than perfect, but present with more smoothness.  With a combination of better clarity, more space, and higher resolution, the NT-6 delivers a more realistic presentation with better transparency that can make the UERM sound smeared and inaccurate in comparison even though the UERM has better forward projection capability.
The NT-6 bass extends noticeably deeper and can recreate more bass rumble and overall output with songs that call for it, giving a visceral feel at times that is missed with the UERM.   Texturing and detail is excellent with both, but the NT-6 has a quicker note on average resulting in a slightly leaner and more defined sound, even though there is more bass output capacity.  The midrange of the UERM is placed a little further back than the NT-6, however the NT-6 gives a more spacious presentation along with having better midrange detail, resolution, and clarity.  Like with the bass, the NT-6 sounds slightly thinner in note resulting in better clarity and airiness of the presentation, making the UERM sound a bit thicker than the it should in comparison.  Treble is slightly more forward with the NT-6 and both taper up, but the treble sounds flatter and is more extended, with the UERM treble sound peaky in comparison.
While both can be involving and musical, they were designed for a flat and revealing reference sound.  The NT-6 gives you more bass depth and weight, higher levels of clarity and detail, and on overall more defined and resolving performance wrapped in a more musical presentation.  However, the UERM has a bit thicker sound and will let you know if your master is less than perfect and has better soundstage depth with the ability to project further.  
SA-43: Both are excellent performers but do things differently as the NT-6 is brighter with a more forward presentation.  While they have different tones and presentations, they share many traits such as transparency, dynamics, and recreation of ambiance with similar soundstage proportions.  With a few tracks that contain large soundstage depths the SA-43 can project further and width of the SA-43 is also superior, but the NT-6 has slightly better focus within the soundstage as well as imaging.  However, the comparison is difficult because the SA-43 is laid back quite a bit in comparison with the NT-6's more forward presentation.  Clarity and detail are superior with the NT-6, with the NT-6 bringing those additional details right to you while the SA-43 makes you search for them in comparison.  Notes are slightly thicker with the SA-43, but not significantly different and both have a very good attack and decay ability, however the NT-6 can sound faster.
Comparing the bass is not as straightforward as with other CIEMs due to the switch.  With the SA-43 switch off the quantity of bass is similar to the NT-6, however the NT-6 has better extension vs. the slightly thicker and warmer presentation of the SA-43.  With the switch on the bass depth is similar, although the NT-6 still has more quantity in the deepest registers, but the SA-43 has more bass quantity overall.  However, with bass heavy songs, especially with deep bass, the NT-6 can easily keep up in quantity and even surpass the SA-43 at times.  The midrange of the NT-6 is more forward and has better detail, articulation, and imaging, recreating a more believable experience with vocals compared to the SA-43 with the presence switch off.  Recordings with 3D spaciousness are recreated with more realism with the SA-43 due to the larger overall space and better projection.  With the presence switch on the SA-43 turned on the midrange is brought forward to almost the NT-6 level, but some artist voices sound somewhat nasally when compared with the NT-6 and with the presence switch off.  The presentation differences make it hard to compare directly because the NT-6 treble is much more upfront, but the both are smooth and have good detail, however the SA-43 is smoother and the NT-6 is more detailed.  The SA-43 has a slight bit more note decay however the NT-6 has better extension.
Overall both are excellent performers and perform their best in different situations and appeal to different preferences.  The NT-6 is more of a reference monitor that excels across the spectrum bringing you all the details in your music with crystal clarity while the SA-43 is more laid back with options to adjust the sound to your liking.  If you prefer to listen to the overall presentation with a great spaciousness, placement, and projection, the SA-43 is the better choice while the NT-6 will recreate vocals in a more focused and convincing way with the ability to recreate individual instruments more realistically.  Both are very enjoyable and highly recommended.
SE 5-way: Both are in the upper echelon of what I have heard, with a very natural sound and high technical ability.  While they are fairly balanced, the NT-6 has a brighter sound with an overall more forward presentation with most songs while the 5-way has more of a bass emphasis and can convey bass power and emotion.  The presentation space is large for both and the proportions are very similar, but the 5-way can present a larger overall space and has better depth of space when extreme depth is in a recording.  Average note decay is a bit longer with the 5-way, and while the NT-6 is very capable with great attack and decay, the 5-way really shines in this area with the best combination of attack and decay I have heard.  This results in the 5-way never sounding slow in comparison with the NT-6, but sometimes the NT-6 sounds slightly too fast in comparison.    Both offer great transparency and clarity, however the clarity is different, with the NT-6 offering a very apparent clarity and at first listen I would say the NT-6 has better clarity, but the SE 5-way has equal technical levels of clarity which are achieved through resolution, layers, and ambiance recreating a more "you are there" feel.  The 5-way is a little more forgiving of poorly mastered/low bitrate tracks.  Source dependence of the NT-6 is less than that of the 5-way, but the 5-way improves more with better sources.
The 5-way has amazing bass, with the ability to deliver more quantity than anything else I have heard, and in a clean and controlled way.   The NT-6 is equally impressive given the sound signature as it has similar headroom even though it doesn’t actually output the same amount of bass as the 5-way.  Both have bass that goes down to the deepest registers, both can rumble, and both have great texture.  With that being said, the 5-way is a little thicker and warmer and puts more emphasis on the bass than the NT-6.  The midrange of both is exceptional and while the 5-way is liquid, smooth, and rich the NT-6 has a similar sense of liquidity, even though there is an analytical nature to the sound.  Presentations are fairly close, but the 5-way has a slightly more mid-forward presentation in the lower midrange/vocal area.  The upper midrange and above diverge in frequency response as NT-6 has a more forward and emphasized upper midrange and treble leading to a brighter sound while the 5-way pulls that area back a bit and gives better depth of the presentation.  Both extend the treble quite a bit and have an air about them, but the NT-6 is a little flatter throughout the treble while the 5-way is better with note attack/decay.  Both are smooth and liquid, but since the NT-6 is flatter in frequency response and equal in detail and dynamics, the NT-6 treble rates slightly higher than the 5-way treble.  However, Grzegorz (the maker of the 5-way) said my fit issues may be a cause for the less than perfectly flat treble.
As stated at the beginning of the comparison, these two are very close in overall performance and the NT-6 was the first custom IEM that really technically challenged the 5-way and made me question some aspects of the sound.  With the NT-6, you get a very technically capable CIEM that is brighter and more analytical than the 5-way with a thinner overall sound while the 5-way gives you ultimate bass capability when well amped and exceptional attack/decay of notes.  But, both offer incredible performance that is extremely enjoyable when not comparing directly.
JH16: With a similar note presentation, the NT-6 and JH16 share some traits, although frequency response at both ends of the spectrum is not.  Both have notes that are on the quick and detailed side, however the NT-6 has a more consistent note across the spectrum while the JH16 seems to thin out a bit in the bass and treble, but is similar to the NT-6 through the midrange.  The biggest presentation differences are centered around the recreation of the soundstage as the NT-6 has better focus and clarity as well as more depth and height to the presentation while the JH16 has a bit more width.  In comparison, the JH16 lacks the definition of instruments in space as well as placement with all but tracks that don't have much depth/height.  Speed is similar between these two and both have very good dynamics and headroom.
There is no question that the JH16 has enhanced bass in comparison with the NT-6, but it is also presented in a more punchy way which for me is unpleasant with some easy listening tracks such as Yes - It Can Happen.  Both recreate the deepest registers and both have very high levels of detail and texturing, however the JH16 has more sub-bass rumble, mainly due to the enhancement,  but the NT-6 does recreate sub-bass ruble.  I was a bit surprised that the NT-6 bass sounded a good deal more precise and well controlled with bass heavy tracks.  Warmth of both is about on par with each other although due to the enhanced vs. flat response there are differences in perceived warmth depending on the track.
The midrange has the biggest quality difference in the frequency range as the NT-6 midrange tonally sounds flat and accurate in comparison with the JH16 midrange, which sounds like the lower midrange is a little recessed, especially in comparison with the upper mids, which have a tendency for sibilance with female vocals in comparison with the NT-6.  Imaging differences are fairly large when there is soundstage depth in a recording, increasing the differences between the midrange.   While the JH16 treble is good, the NT-6 treble is a real strong point and has a flatter in-ear response as well as a slightly longer note decay leading to a more natural and sustained note.  The midrange of the JH16 does have a liquid quality, but the NT-6 matches that liquidity with more precision and ambiance recreation.
Aside from the note presentation, these two sound like they are made for different audiences: the JH16 is for someone who wants enhanced bass and listens to today's pop music while the NT-6 is for those who want accuracy and the ability to recreate the imaging in well mastered music.  Both have a very wide frequency response and cost about the same so it comes down to music preference and ultimately, use.  I could see a stage performer going for the JH16 for the fun sound while a studio engineer would really appreciate the NT-6.
LS8: While these two aren't too different, they do have different frequency response characteristics and presentation difference.  The LS8 is warmer with more bass punch compared to the brighter NT-6.  Both have very airy sounds and give a complete, well rounded presentations but the NT-6 has a little more overall space as well as a more 3D presentation, although not nearly as large of a disparity as with the JH16.  Technically, the NT-6 has better imaging, clarity, and transparency while detail levels, resolution, and speed are similar.  The LS8 holds the edge in smoothness, with a more liquid, forgiving presentation compared with the more analytical NT-6.
With more bass emphasis and warmth, the LS8 is a capable performer, however the NT-6 bests the LS8 in reproducing sub-bass rumble and is slightly more precise in direct comparison.  Other than some minor quality differences, the bass quality is similar.  The midrange is similar between these two except the NT-6 has better imaging by a bit along with the tonal differences of vocals due to the warmth differences.  In the upper midrange the LS8 has a peak while the NT-6 has a bump; much less prominent.  This bump carries over into the treble with a gradual increase resulting in a smooth and pleasant response while the LS8 can have a tendency to accentuate the occasional sharp 'S'.  The treble flip-flopped for me, with some tracks being more forgiving and liquid with the LS8 while other tracks that were mastered better sounded silky smooth with the NT-6, leaving the LS8 behind.
Both perform at exceptional levels, with the LS8 having a more forgiving and liquid presentation resulting in a more musical experience with a warmer and more bass centric sound.  Conversely the NT-6 has a treble emphasis in comparison along with a more analytical sound.  Technically the NT-6 is more competent with a superior overall soundstage recreation, but they aren't too far off, and the LS8 could be a better choice for someone that want a warmer presentation. 
EM3 Pro: With a thick and warm presentation the EM3 Pro is very different than the NT-6, and both bring out the bad points of each other.  Technically the NT-6 has much better clarity, detail, and a sense of speed.  The EM3 Pro has more warmth/richness and is more forgiving because the treble is at a much lower volume in comparison with the rest of the spectrum, especially when compared with the bright NT-6.  There is a greater sense of depth and space with the EM3 Pro than with the NT-6, however the NT-6 has a wider soundstage.
Bass quality with the NT-6 is far superior with much better detail, texturing, and extension but the EM3 Pro has more bass quantity.  The midrange is vastly different as the NT-6 is clean and clear while the EM3 Pro is warm and rich with less detail but more ambiance due to the soundstage depth.  Treble is also vastly different since the NT-6 treble increases gently as the frequency increases while the EM3 Pro treble has much less quantity.
All in all these two are complementary and not competitors.  Technically the NT-6 is superior but the EM3 Pro does offer a fun sound with great depth to the soundstage that adds ambiance to the presentation giving it a special feel.
EP-10 Plus: The differences between these two are night and day.  One is accurate and precise without any bass emphasis while the other is a mid-bass monster, so much so that there is a veil.  There is no need to write too much more because if you want one, the other will either be the ultimate complement, or you won't want it!
CK10: Since I think the NT-6 sounds very much like a CK10, I borrowed a CK10 for comparison purposes.  These two share characteristics in the midrange, so when there is only midrange present, especially with simple music such as vocals with a little background music, the differences are small.  When comparing the overall sound, the CK10 is mid-forward in comparison while the NT-6 has a bit more upper midrange/lower treble emphasis, but the midrange and treble are more filled in.  Bass quantity is in general quite similar as the CK10 is capable of reproducing deep bass notes, however the recreation on the NT-6 has more power and reverb ability.  The tone of the bass notes can be different depending on the depth of the bass note as the CK10 runs out of steam in the sub-bass region while the NT-6 keeps going strong resulting in more body, reverb, and punch.  Differences in the treble region are even bigger as the treble of the NT-6 is more present, detailed, articulate, and focused leading to a presentation that is cleaner, clearer, and more realistic.  The treble region of the CK10 sounds rolled off in comparison.
While clarity of the midrange isn't too far off between the two, the NT-6 is a good deal superior at both ends of the spectrum.  That is combines with more depth to the presentation, much higher dynamic range, and better focus within the presentation resulting in the NT-6 being able to recreate music in a much cleaner and clearer way, with instruments making music while the CK10 sounds like it is pushing out notes in direct comparison.  Due to this presentation difference, the NT-6 is more transparent while retaining coherence even though it is a 4-way design.  Attack is similar but the NT-6 can sustain notes longer resulting in a wider variation ability for the decay, especially at the frequency extremes.  The NT-6 is the closest to the CK10 that I have heard and is clearly a step up, and a good one at that, but at a very large price premium.    
Volume performance: As with many balanced armature CIEMs in the price range, the NT-6 bass takes a little more than extremely low volumes to get the bass to really kick in.  Low level volume performance in the bass region is top notch and the sound signature is retained from low through high volumes.  At higher volumes the quality levels don’t decrease in the slightest.
Sound Summary: The NT-6 gives you a neutral, high resolution, accurate presentation reminiscent of the CK10 but technically better in every way by a significant margin.  Not to be confused with something thicker and richer such as the 5-way or EM3 Pro, the overall sound is on the thinner and analytical side, but is not lacking in bass power or depth when a track calls for it.  Imaging is special and the space is on the larger side of the CIEMs I have heard, with good depth and height resulting in excellent instrument placement.  Resolution and detail levels are phenomenal, only being bested by the SE 5-way. 
Combing all the above with exceptional dynamics and the ability to change to the track and with the source, the NT-6 creates an emotional experience while serving up all the details to you very clearly.  If you want to easily hear all the nuances in your music for any reason, from mastering to musical enjoyment, the NT-6 is an excellent choice with incredible technical performance for its sound signature.  When combined with a very resolving source such as the 801, the NT-6 recreates an experience that duplicates the live feel of a performance.
[size=13.0pt]Source matching[/size]
Portable Sources, DAPs
Clip+: This pairing is adequate considering the price of the source, but not as good as I am used to with higher end sources (of course).  The bass depth isn't quite there, although there is plenty of bass.  The space isn't all that large, although it does have some decent 3D proportions to it.  Overall the Clip+ is an OK performer that has a nice frequency response balance and will please many people on the go when they can't pay full attention to the music, but the Clip+ doesn't take full advantage of the NT-6's capabilities. 3/10
iTouch 3G: In comparison with the iPhone 4S, the iTouch 3G is slightly thicker and warmer with  better control of the bass and a bit more depth and openness to the soundstage.  4.5/10
iPhone 4S: In comparison with the Clip+ the 4S has more dynamics with a slightly less accentuated treble and more deep bass presence, but otherwise they are similar in frequency response.  The overall presentation is slightly smoother and cleaner leading to an enjoyable presentation for the minimalist on the go. 4/10
iPhone 4S with i.Fuzen amp case: With a different tonality compared with the headphone out (HPO), the i.Fuzen is more laid back and spacious with a little bit less emphasis on the upper mids and treble.  Due to the wider soundstage with better depth, the i.Fuzen can make some spacious tracks really shine in comparison with the HPO, while tracks without depth have little difference.  Clarity and instrument separation are also superior with the i.Fuzen, and the overall presentation is more dynamic and punchy when a song calls for it.  The Bass from the i.Fuzen is punchier and has more deep bass energy.  All the individual improvements to the sound add up to a significant improvement over the HPO.  6/10
801 (with GAME card): Exceptional match as the 801 really recreates a great spatial experience with the NT-6 and the frequency response of the 801 synergizes well with the NT-6.  Detail levels are excellent and there are no volume issues except at ultra low listening volume. Overall this is a very musical, accurate, and detailed presentation that I could listen to all day!  9.5/10
Portable Sources, DAPs with Amps
Modded iPod -> Note: the changes between the amps are not all that large, just small differences noticeable with A/Bing.  The overall performance is below that of the 801 and D1 but greater than the other portable players and lower cost desktops.
Arrow 12HE: With a warmer presentation and thicker note the Arrow pairing moves the NT-6 in a different direction.  Deep bass isn't as authoritative as the other amps due to roll off and there is less treble than with the SD and PS.  The space is, as usual for the Arrow, wide but the depth doesn't seem to be altered, which is a very good thing!  Resolution isn't bad, but is a step below the PS and SD.  6/10
Pico Slim: The PS has a slightly thinner note than the others and while this isn't an issue, it does make a slight difference, especially with extended listening sessions.  The space isn't quite as large as most of the competition, but the PS is very transparent with great clarity, not imparting anything on the sound.  However, the amp does hold the NT-6 back a bit in soundstage size in comparison with many others.  6/10
Stepdance: There is a slight bit more smoothness and liquidity when the NT-6 is combined with the SD, to go along with a slightly more laid back presentation.  The depth of the presentation and black space are excellent, making this combo very enjoyable.  7/10
Neco V2: The V2 performs quite well with the NT-6 with minor differences to the SD, which is a slight bit more laid back.  The very small changes make the V2 a great match for the NT-6 at a very low price in comparison.  7/10
uHA-120: The uHA is between the SD and PS.  In comparison with the uHA, the SD offers a little warmer presentation with a bit more space and the PS offers a bit better transparency and a slightly brighter presentation.  The changes aren't large and the uHA should do fine other than volume balance issues at low volumes, which reduces the score.  5/10
D10: The first thing I noticed was that the quality of some vocals on a Snoop song sounded harsher with the D10 vs. the SD.  This is not saying the amp is bad and there is a price disparity, but the overall performance has a little less space and depth of the presentation compared with the SD.  5/10
Cruise: With speed and punch, the Cruise plays to the strengths of the NT-6 and accentuates them.  The presentation is detailed, with the highest resolution of the bunch, and immediate.  Decay for bass heavy tracks doesn't have quite the decay as something such as the SD or V2, but the presentation is amazingly quick.  There is a bit of continuous hiss that can be heard at very low volumes and between tracks, lowering the score a bit.  7.5/10
Desktop Sources
TTD v2: Starting with the negatives, the background is not black as there is hiss, but even worse, noise when no music is playing and there is a channel imbalance at low volume.  On to the good...the sound, or at least some parts of it.  Other than the noise and hiss issues, when the volume is mid level or above (louder than I typically listen), music is presented with warm and rich overtones that are very pleasant; unfortunately with many songs the hiss levels are too high for me.  With detail levels on par with sources in the price range, the TTD v2 isn't the best match with CIEMs.  However, when combined with a good amp, the TTD v2's rich, warm presentation is very welcome and musical.  The speed with the NT-6 is great and the fuller sound is welcome.  1/10 as a DAC & amp, 5.5/10 as a DAC with an external amp
D1: Exceptional clarity, resolution, and imaging give this combination a great sound that isn't lacking in any area.  The D1 give an immediacy and sense of ultra-clarity and detail that is easy to hear.  The D1 allows the NT-6 to technically perform at a top level, however the presentation is on the thinner side, but the overall result is still very engaging and immersive.  10/10
Source Summary: While entry level DAPs certainly don't sound bad with the NT-6, they don't bring the dynamics, excitement, or detail of the higher end hardware.  When the detail level from the source (DAC) is increased there is a direct correlation to the quality of the music recreated; the NT-6 is very source transparent.  It is a fairly easy to drive CIEM so other than amp sound signatures, there isn’t much difference between high quality portable amps.

Note: I find the Whiplash Hybrid V3 cable is an exceptional match with the NT-6 and pushes the performance to another level.  Read more here.
While providing a 'reference' sound, the NT-6 excels with exceptional clarity, imaging, dynamics, and doesn't roll off on either end.  The NT-6 isn't shy about pointing out flaws in other CIEMs when compared directly and doesn't exhibit many flaws itself, which is indicative of the very high technical performance.  The biggest weakness of the NT-6 is that the depth of the presentation isn't up to par with a few others in the price range, but the differences aren't too large and are dependent on your music.  Bass is neutral but still has great dynamic range, depth, and the ability to rumble with deep, reverberant bass notes.
Accessories are decent but not without issue.  The case is very attractive but a bit small and I often had issues closing it.  Also, the NT-6 has a non-standard cable, which is microphonic so additional purchases of replacement items may be a necessity from the start (Hidition has another cable option).  However, taking into account the sound, the NT-6 is still an exceptional value due to the high level of sound quality and build quality.  If you want or need a monitor that will reveal all the nuances in your music precisely without rolling off on either end while still providing an involving performance, the NT-6 delivers!
-       Exceptional clarity, imaging, and dynamics
-       Deep bass extension and extended treble
-       Extremely flat frequency response
-       Extremely high technical performance for the price
-       The upgraded cable is microphonic even though it uses an over-the-ear design (I will update when I receive the standard cable)
-       Carrying case is on the too small side, resulting in issues closing the case (Hidition is working on a new, larger case)
Similar sounding Headphones/IEMs: CK10, DBA-02, UERM
Jan 7, 2012 at 9:29 AM Post #3 of 992
from wher ei stand, in the last year or so, JHA and UE is losing their grip on the CIEM market. kudos to all the great companies making great products!
Jan 7, 2012 at 11:04 AM Post #5 of 992
Nice review as usual you are a beacon of light in custom IEM's.

Thank you!
from wher ei stand, in the last year or so, JHA and UE is losing their grip on the CIEM market. kudos to all the great companies making great products!

The JHA and UE products are good and competitive, but ultimately they do have some room for improvement.  Hidition has been around for a while as other CIEM manufacturers, but there has been little to no head-fi exposure.  And the contrast brings out the strengths and weaknesses of everything.  For example, I really like the UERM with well recorded tracks, and the soundstage recreation when paired with the 801 to an amp is amazing (and has better depth than the NT-6), but I had no idea about the issues mentioned above until I compared it directly with the NT-6.  You could say it doesn't have those issues unless you compare with something better :wink:
Great review. The cable you have is the Premium cable they sell.

OK, thanks.  I have updated that in my review.  Do you find it microphonic?
Jan 7, 2012 at 5:59 PM Post #10 of 992
interesting review

Predictable response.
I was interested in them when I saw the Golden Ears measurements...

Yes, those charts are nice and all but unless they are all done the exact same way, it is hard to get the true characteristic of something IMO.  Although they do have their place.  And the rating between clear and veiled has me scratching my head.  I wonder what would rate a 5?
Yeah its very microphonic. I use the Chrishimself silver cable instead but I find the sound a little to bright. I have ordered a gold plated copper cable from him.

OK, so it wasn't just me; hopefully they will fix the issue.  And interesting about the copper cable...too bad I had to send the Double Helix cable back.
Thanks for the nice review! I found the comparisons (especially to the LS8) particularly informative.

No problem, let me know if you have any questions.
Jan 11, 2012 at 11:34 AM Post #14 of 992
Yeah, it's a bit puzzling; I guess only people with golden ears will know... we should try to set up an appointment with King Midas one of these days.
Yes, those charts are nice and all but unless they are all done the exact same way, it is hard to get the true characteristic of something IMO.  Although they do have their place.  And the rating between clear and veiled has me scratching my head.  I wonder what would rate a 5?

Jan 12, 2012 at 2:33 AM Post #15 of 992
Did you get a frequency chart with it?

Yes, but I do hear the upper registers different than the graph.  I have also seen graphs provided to someone interested in buying and the NT6 graph looks fairly different than mine.  I am not sure how much the graph will help things out.
Yeah, it's a bit puzzling; I guess only people with golden ears will know... we should try to set up an appointment with King Midas one of these days.

Ha, I guess.  At least they are trying to quantify things which in the grand scheme of things could be good.  You have to pick what is "neutral" and go from there.

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