[Review] UM Merlin, FS MG6Pro, AKG K3003

Unique Melody Merlin
 
 
Foreword:
 
At the time I ordered the UM Merlin, I had been a registered Head-Fier for right at a year, and like many members who have been around any length of time, had run the gamut of mid and top tier universals.  I have had a great time buying, selling, trading and borrowing all kinds of universals with different sound signatures, ergonomics, materials and drivers, and still to this day continue to enjoy doing so.  I’ve also come to enjoy putting my experiences into reviews, impressions and random posts as the mood, excitement or disappointment strikes.
 
I’ve come to know many of you quite well, or at least as well as you can know strangers and acquaintances through a forum.  I have learned quite a lot from many of the experienced regulars here and feel my ears have become a very well trained tool over this time period but know I still have much to learn and experience.  I just want to express my gratitude to those that share PM’s and emails with me, answer my questions and humbly say thank you to all those that put their trust in me, by asking for my advice in their hunt for a sound that meets their needs and desires; or who simply enjoy reading my thoughts on this phone or the next.  I’ve come to love Head-Fi and this hobby and hope in some small way that my participation helps it to continue to grow.
 
Background:
 
Back in mid September of 2011, UM Global offered a promo special for the Americas (and later to other regions) that included a 20% discount on the custom of your choice, a UM branded USB drive, T-shirt and an AmpCity Fortis custom made silver cable.  The promo launched on September the 15^th and took the first 25 to sign up.
 
We all shipped our impressions to a specific Head-Fier, who would in turn packed them all up in one box and sent them to UM, who would then reimburse him for shipping costs.  Due to logistics and paperwork for so many involved, it was roughly one month after placing the order that our impressions were finally shipped off to China.
 
During the long wait for our CIEM’s to arrive, UM announced in early December that they were changing the T-shirt to a track jacket and we learned the supplier for the Fortis cable wire could not deliver as promised and AmpCity  were sourcing another avenue.  Due to this delay, UM decided to include a stock cable, for free, so they could go ahead and ship all the phones once they were ready.
 
Finally the day arrives!  December 16, 3 months from order date, a perfect fitting Merlin arrives in my possession.  Perfect fitting you say?  Completely.  I cannot stress enough how important well made impressions are.  The audiologist I used makes impressions for musicians on a daily basis.  I of course paid a little more but I find the expertise and experience worth the extra costs and perhaps saved me more money, in the long run, in shipping costs for refits.
 
As of today, the Fortis cable and track jacket have still not been delivered.  UM is still awaiting AmpCity to deliver.
Edit: The redesigned Fortis cable, made by Beat Audio, arrived May 17, 2012.
 
Design:
 
The Merlin is a hybrid 3 way design using dual BA for highs, dual BA for mids and a single dynamic driver for lows.  It is also a vented design, allowing for air movement, creating a greater presence of bass and spaciousness.  Despite the venting, isolation is very good.  I ordered mine with recessed sockets but flush sockets are available.  Warranty is 2 years with 60 day refits and specs are as follows:
 
Crossover – 3 way
Frequency Range – 10hz to 19hz
Sensitivity – 108db
Impedence – 12 ohm
 
This equates to the Merlin being fairly easy to drive but you’ll definitely want low output impedance from your players or amps.  Certainly nothing greater than 2 ohm and less than 1 is recommended.
 
 
Packaging:
 
The Merlin comes in a giant red box with a standard 50” Westone/JH style cable, warranty card, cleaning tool, shirt clip and frequency response graph.  The graph is a nice personal touch but I’m not sure how useful it really is, since the method for testing is unknown.  Graphing CIEM’s is a much more difficult task than universals.  Unfortunately it doesn’t come with a pocketable or travel case.  Currently I’m using an Otterbox 2100 that I had on hand but am looking to get something smaller.
 
 
Equipment:
 
Most of my listening is done on the move, whether commuting, walking or moving from one room in the house to another, so my testing is done on portable/transportable equipment.  I’ve used an iPhone 4, Nano 6g, Laptop, Headstage DAC cable and Objective 2 amp.
 
 
Sound:
 
UM markets the Merlin as their north of neutral bass oriented ‘fun’ offering, with a focus on deep bass.  These are not musicians’ monitors but a CIEM created with personal listening in mind.  I myself find that I prefer lows that are somewhat elevated from neutral, as I think it sounds more natural.  In my experience, a properly done low end will have great texture and rumble, without the need to elevate through EQ or bass boosts and adds to the overall musicality.  The Merlin captures this very well, all with zero interfering or bleeding into the midrange, as well as not becoming overpowering or stealing the focus of a song.
 
Bass is indeed natural and plentiful.  Bass guitar becomes the driving rhythm of a song.  It extends very low and is some of the tightest and cleanest bass I’ve heard in my IEM journey so far.  In a word: Palpable.   Kicks are extremely tight and punch with authority.  Decay is very believable, yet it’s no slouch in speed.  There is no sign of slowness and congestion.  Texture is simply sublime.
 
To put the bass in context, I find the Future Sonics Atrio with MG7 driver to have more sub bass quantity/volume but sounds a little loose and uncontrolled in direct comparison.  If you are familiar with the MG7, then you know it has some of the best deep bass in the universal business.
 
As you expected, bass is very, very good on the Merlin.  What you might not expect are the utterly liquid, thick and lush mids.  I cannot tell you how pleasantly surprised I was to discover the Merlin is a mid-centric phone!  Voices take front and center for a very intimate performance.   During a recent A/B with the RE262, these were my notes:
 
“Both are mid centric with sweet, intimate and liquid vocals.  Due to the RE262 not having as much of a bass presence, vocals are not quite as fleshed out as the Merlin but make them appear just a tad sweeter and closer.  Overall the Merlin produces better clarity and detail in the vocals providing for an extremely intimate performance.”
 
The Merlin, like the RE262, excels at giving you the finer nuances of vocal performances: pursing of the lips, intakes of breath, throat inflections and raw emotion.
 
The very thick noted midrange also produces fantastic distortion rock guitar sustain.  In this manner it produces a very Marshall inspired lifelike performance.  Here is a note I made while listening to a Sevendust song:  “Drop D guitars are thick with gobs of sustain, along with the rumble of the bass guitar create the wall of sound Sevendust is famous for.”
 
Moving on the highs, I find them very crisp and a bit on the airy side.  Sparkle is excellent.  The Merlin treble never gets fatiguing despite the crispness and sparkle.  Hi-hats and cymbals are rendered with very good clarity and produce excellent location cues.  If I could change one thing on the Merlin, I’d perhaps want to add just a bit more weight to the high end but then again I don’t know how that would affect the overall presentation.
 
The soundstage of the Merlin was the biggest revelation for me moving to a custom.  It took me days to wrap my head around what I was hearing; and then finally it dawned on me: Height!  The Merlin soundstage is without a doubt the tallest soundstage I’ve heard.  When I immediately switch to one of my universals, until my brain can readjust, it makes them sound very short in stature.  The Merlin soundstage is also both very wide and deep, as well as placing you very close (front row) to the stage and looking up at the performance.
 
One of the aspects of BA’s I’ve noticed is their ability to separate instruments.  Instrument separation on the Merlin, with the quad BA’s, lives up to this expectation.  Each instrument is distinctly rendered with plenty of air around them but most importantly there is great coherence between dynamic driver and BA’s.  Kudos to UM for pulling it off; so nicely done.  However it is worth noting, that to me, BA’s do not present music as organically and blended as a single dynamic driver and this speaks to the sense of instrument separation that BA’s present.
 
From here I’d like to expand just a little about how certain instruments are presented with the Merlin.  Drums sound utterly fantastic to me.  Every piece of the kit is easily heard/pinpointed.  Snares and toms have huge impact and sound very lifelike. Hi-hats, cymbals and rides are easily distinguished from each other.  Pianos have proper weight and reverb down low, and sound wonderfully thick with a very good top end.  Acoustic guitars have lifelike resonance.  But my favorite has to be the phat distortion guitars and the amazing sustain.
 
 
Conclusion:
 
As you can see the entire process dealing with the UM promos has been trying and time consuming.  As much as I love how the Merlin matches my preferences, I’m not sure if I would go through that many months of waiting again.  Just for the CIEM themselves, the wait was 3 months and we are at 5 months and counting for the promo items.  I suspect waiting times will be less in the future, without regional promo orders clogging the gears.  Never-the-less, when considering ordering a CIEM from a manufacturer outside of your home country, there are bound to be time related frustrations.
 
The build quality and sound of my Merlin is superb and lived up the reputation and expectation of a UM build.  If you have the patience and have been on the fence about the Merlin, I hope I’ve covered many of the questions and concerns you may have.
 
Up next?  Well a Future Sonics MG6Pro is what’s next.  Impressions were sent off to FS as this review was written.  I’m keeping the next few posts reserved for the incoming MG6pros and whatever else may follow.  An Aurisonics AS-2 this summer perhaps?  To be continued…

Future Sonics MG6Pro
 
 
 
Foreword:
 
If you’ve read any of my previous reviews or impressions, you know I’ve been a fan of dynamic drivers for a long time.  In general, I find them to be more textured in the low end and overall portray a more natural or realistic sound for most instruments.  As of recently I’ve rediscovered a love for the separation, layering and intimacy many great balanced armature designs bring to the table.  Some have believed that hybrid designs could possibly bring out the best of both worlds.  I guess you could say that I’m a believer too, as I am quite fond of the UM Merlin and its musical and engaging presentation; but for anyone that’s a fan of dynamic drivers, that means you’ve ultimately had your eyes on the Future Sonics MG6Pro – with its 13mm driver and heritage from the Atrios line, known for its unmatched sub bass performance.
 
Background:
 
I’ve been considering and ultimately planning to purchase the MG6Pro for many months.  It just so happens I stumbled into a UM group buy that eventually led to a UM Global Promo event, that ended up postponing my plans for the MG6Pro but back in mid February, I decided to take the plunge on what I hoped was the dynamic driver end game.
 
I decided to have my impressions taken with the same audiologist that did them from my Merlin purchase, since those turned out so well on the first try.  Turnaround time from Future Sonics receiving them to shipping them back to me was a little over 3 weeks.  Turns out they had a very large order for the singing competition, American Idol, which was placed around the same time.
 
The Carousel:
 
Upon receiving them, the first thing I noticed was the classic fit issue.  They were too small in areas and easily lost seal.  I noticed that I was also experiencing a lot of harshness and an echo effect that made them very fatiguing to listen too.  I immediately contacted Future Sonics customer service, which were very friendly and professional.  They ask me to send them some pictures of CIEM’s in the ears to determine if a refit or complete rebuild would be necessary.  Unfortunately a complete rebuild ended up being necessary, so I had to return to my audiologist for additional impressions.
 
Since this time, I have learned several things regarding impressions, molds, and the CIEM final product.  The first is that the customer plays a large part in the quality of the impressions.  For instance, did you clinch your jaws or where you relaxed?  Did you look down or look up too much?  Did you schedule them when you were sick or dealing with allergies?  Secondly it is also important that your audiologist follow the manufacturer’s directions in making the impressions.  Did they use a bite block? Do they have experience with musician’s monitor impressions?  They are made slightly differently from hearing aid impressions, as they require a tighter fit and closer tolerances.  And lastly the manufacturer can indeed make mistakes along the way, as confirmed from other members of this trade, from trimming the impressions, to the shaping and sanding stages and lastly when polishing the final product.
 
After sending in new impressions, along with the CIEM’s themselves, Future Sonics also graciously allowed me to change the color from purple to smoke.  I’m guess I’m just not much of a flashy person when it comes to accessories.  I received the rebuilt set in early April.  Unfortunately I needed to send them back again, due to the nozzle portion of the right ear causing some discomfort and well as both faceplates sticking out from the ear too much.  I received a great fitting pair of MG6Pros in late April but unfortunately the issue of the harshness and echo effect, from the beginning, was still there.
 
The harshness and echo effect I was hearing seemed to be coming from the 2k and 3.5k ~4k areas.  It was explained to me that Future Sonics has some peaks in the frequency response there to help balance the overall sound presentation out with the bass response.  My sensitivity to these peaks seems to be greater than most, as Future Sonics has never had anyone complain about a harshness.  It causes the tops of vocals and edges of guitars to become painful, fatiguing and ‘echoey’, which obscures details.  Also cymbals in busier drumming passages became blurred, creating a lack of treble detail and some ringing.  It’s as if someone turned the ‘presence’ knob to 11 on a guitar amp.
 
Upon sending them in for the 3^rd time, along with some music tracks so that the techs and owner could hear what I was hearing, it was decided to rebuild and replace the components (which they do on any rebuild), to rule out any other possible attributing factors.  I’m doubtful the Future Sonics staff was able to hear what I was hearing but they assured me the last set had passed their listening tests for the sound Future Sonics is known for.
 
I received my MG6Pro for the 4^th time in early May.  The harshness, echo effect and blurred treble detail remain.
 
 
Design:
 
The MG6Pro contains a new, proprietary 13mm dynamic driver.  The shell is vented in the center of the faceplate.  It comes with 3 different sized vent inserts (S, M, L).
 
• 18Hz - 20,000Hz TrueTimbre™ Response
• 32ohm Impedance
• Sensitivity 114dB @ 30Hz 
 
Future Sonics also includes a future $199 upgrade path for when new versions of the driver are released.  Upgrades include the new driver, sockets, vent inserts, cable and are performed with your existing molds.
 
Packaging:
 
In addition to the cable and vent inserts, Future Sonics includes an Otterbox 2000 that is custom engraved with the buyers name, as well as a pleather pouch for keeping your CIEM safe.
 
 
Equipment:
 
Most of my listening is done on the move, whether commuting, walking or moving from one room in the house to another, so my testing is done on portable/transportable equipment.  I’ve used an iPhone 4, Nano 6g, Laptop, Headstage DAC cable, WhipMod 5g iPod and an Objective 2 amp.
 
Sound:
 
Future Sonics marketing states the MG6Pro sounds as:
 
“The mg6pro™ are multi-driver & crossover free; delivering full range audio w/ natural hi-end sparkle, warm mids and a low-end frequency response no two, three, four or more way balanced armature earpiece can touch! mg6pro™ Ear Monitors® audio signature, reliability and workmanship allow performers to hear themselves with exceptional clarity; while our BIGGER SOUND at lower volume™ promise continues to deliver the best sonic performance possible.”
 
Bass is first and foremost the allure and attraction for many to the MG6Pro.  In this respect the MG6Pro does not fail to deliver.  It has a great sense and feeling of power, unlike anything I’ve heard or felt in an IEM before.  It really can move a lot of air.  The following statement came from another head-fier in a discussion we had regarding dynamic drivers in general but I really think it applies to the MG6Pro:  Most IEM’s reproduce the sound of bass, rather than produce bass itself.  The MG6Pro produces BASS.
 
That being said, I find the bass of the MG6Pro to be much too big for my tastes, even with the smallest vents.  The entire bass range is elevated and increases presence with the larger vents; this increased presence makes the bass bloom, lose tightness and mask texture.  This increased presence also affects the lower midrange, obscuring details here and robbing male vocals of clarity and a musical presence.  Compared to the Merlin, the overall bass quantity in both sub and mid bass is a good bit larger in the MG6Pro.  However the Merlin has much less mid bass presence and tighter sub bass that reveal more texture, as well as not affecting midrange clarity and detail.  Applying some EQ to remove the bass bloom around 250hz and lower, the MG6Pro bass displays better texture, improves tightness and allows lower midrange clarity and details to shine.  Overall quality of bass is greatly improved but overall quantity is still very plentiful.  Further EQ to remove bass throughout the entire lower region brings better overall balance across the frequency response. (Note: I use the medium sized vents when using EQ.  The reason for vent choice will be discussed later in the review.)
 
The midrange of the MG6Pro, especially the upper midrange, is a bit of a Jekyll and Hyde presentation for me.  The lower to middle frequencies of the midrange (500 – 1.5k) come across as laid back and slightly recessed.  It definitely takes a back seat to the bass and upper midrange/lower treble (2k – 4k) areas.  Deeper male vocals fall behind lead guitars and drums, especially in busy passages of hard rock and metal, and even more so during bridges, choruses and leads.  However the upper midrange has some very forward peaks, which seem to cause unwanted resonance with my ears.  This upper mid peak is what causes the tops of vocals and distortion guitars to appear harsh to me.  Some singers in some songs are just too strident and it quickly becomes fatiguing and I find myself clicking to the next song.  For instance, in any classic Van Halen song, Michael Anthony’s backing vocals are very piercing and echoey. 
 
These peaks in the upper midrange become harsher as the vents become smaller, so while I prefer the un-EQ’d bass of the smallest vent, I’ve resorted to the medium vents for the slightly less accentuated upper midrange peaks.  This effect on the upper midrange causes vocals to become less detailed and un-engaging.  Comparatively, the Merlin vocals are more transparent, detailed and engaging with a real sense of intimacy.  By EQ’ing these peaks down a few decibels, I’m able to remove the harshness I hear and eliminate the ‘echoey’ effect.
 
Treble can be hit or miss for me depending on the type of song and the recorded quality.  When listening to a higher quality recordings for acoustic and singer/songwriter tracks, treble is laid back but cymbals, rides and high-hats are weighty and sound very realistic.  There isn’t any overly bright emphasis that some earphones put on top end; however it is somewhat pushed further back in the overall presentation.  On lesser quality recordings and very busy drumming passages in hard rock and metal, the upper mid/lower treble peak causes it to blur details and cymbals to run into each other producing a ringing effect.  However, when I EQ the upper mid/lower treble range down by several decibels to remove the harshness and echo effect, cymbals/rides/hi-hats are rendered superbly, with high levels of detail and fantastic timbre.  Also EQ’d up in the upper treble frequencies; it becomes possibly one of the most realistic treble I’ve heard.  Again, treble weight comes across to me as nearly perfect.
 
Regardless of vent insert size, I find the overall width of the soundstage to be slightly below average, which was surprising as I usually associate venting as having more of an impact on soundstage width.  Instruments seem very close together from right to left, which also negatively affect imaging.  However the soundstage depth is among the deepest I’ve ever heard. (note: The upper mid/lower treble peaks exacerbate the soundstage issues.  It does open up with EQ.) In contrast the Merlin soundstage is both wider, by a considerable margin and also taller. The MG6Pro serves up a very blended, organic and coherent presentation.  It’s quite the opposite of your typical balanced armature presentation that tends to separate every instrument in its own space within the headstage.  Again, in my case with proper EQ, instrument realism is very convincing; at times I feel like I’m in the same room with the piano, acoustic guitar or drum kit.  While the MG6Pro has a very natural tone, I do find transparency takes a hit at the expense of the massively thicker note and accentuated bass response.
 
Conclusion:
 
It bears repeating, that to my knowledge, I am the only one to experience the harshness, echoey and blurring effects I’ve described in my review.  It’s also not typical to discuss how an earphone sounds after EQ in a review but due to the apparent resonance issues I have with the Future Sonics tuning, I felt it important to bring this into the discussion.
 
Edit: Since the original writing of this review, I have received PM's from 4 to 5 other mg6pro owners confirming that they too hear issues similar to what I've described, albeit to differing levels.
 
 
In Sinocelt’s reviews, I found the tool he often referenced, http://www.phys.unsw.edu.au/jw/hearing.html, extremely useful in determining where the frequency peaks and valleys were located.  I also used the iPhone app, FreqGen, to further pinpoint these peaks and valleys.  After spending a few hours precisely pinpointing my issues with these tools, I was able to create this EQ curve using the iPhone app Equalizer:
 
This interactive chart, http://www.independentrecording.net/irn/resources/freqchart/main_display.htm, shows where various instruments fall within the frequency range and how the various areas can affect how you hear them; thus explaining what the 2k and ~4k peaks were causing me to hear.
 
 
It may sound as if I don’t like the MG6Pro and that would be true, due to the issues I am hearing.  I simply cannot listen to them un-EQ’d for any length of time but I do find I can enjoy them once the peaks are taken away.  The stock tuning is sadly disappointing and, in my opinion, tragically flawed. 

Reserved for Aurisonics AS-2 and ASG-2.
 
 
I spent the morning (July 20), using my new headphone/amp switcher, conducting extensive a/b comparisons of the ASG-2 and TG334. My findings were considerably different from Eke's.
 
Firstly I can agree that the G2 and TG334 share a similar frequency response in general. They both have strong bass presence with a forward midrange and gently downward sloping trouble; and they both present this sonic signature very well- both are engaging and a joy to listen to but I definitely hear significant differences, which affect the overall all feeling, emotion and tonality of presentation.
 
Both have very nice midranges but this is where I also find the most significant difference. The TG334 has noticeable more forward upper mids, which lend to a brighter overall signature with better transparency, smoother transients and wonderful delicacy in vocals. As a consequence the G2's mids sound not only much warmer but also have a rawness about them.  I don't hear the delicacy in the G2 but rather  a bluntness (in comparison). This may come across as less emotional or intimate in vocal performances but then lends to an aggressive rawness for rock, which I very much enjoy.
 
Paradoxically, even though the TG334 sounds brighter to me, the G2 has bit more treble presence. I really like the blend of the full range dynamic driver here, overlapped with the dual BA. Treble on the G2 has more weight and thus better timbral realism. The TG334 treble sounds slightly lighter (in comparison) and crisper. I really like the better articulation of the TG334 treble but would happily trade it for the tonality of the G2 treble.
 
The differences I hear in in the midrange and treble are born out in the various test tones I compared in my FreqGen app for the iPhone. The tones also showed very similar bass extension.  I find the G2's bass notes harder edged but both seem to have very similar decay. Surprisingly the treble extension was basically equal as well using this app, although they have different elevations: between 7.5 and 8k for the G2 and the TG334 has less variance on either side of that range, with maybe a small peak at 10k.
 
I look forward to doing this same comparison again, once my custom AS-2 returns, as I remember it having a few differences in presentation  and technicalities from the generic version. To tie back around to Eke's assessment, even though I hear them pretty different in mids and treble, I can consider them brothers from another mother- the G2 being the little brother of the TG334.
 
The ASG-2 is awesome fun, I whole heartedly recommend it!

Reserved for ?????

 
 
Before jumping into the sound, I want to make a few comments on build and accessories, which I feel are important to discuss, due to how they may affect the sound and/or durability of the product.
 
Accessories include 3 pair of stock single flange tips that are very comfortable and well made with a good combination of thickness and flexibility.  My only issue with them is that I require a bit deeper insertion due to the shape of the housings and tip length; I can’t quite reach optimal positioning.  I had some extra Meelec triple flange (trips) tips lying around and these solved the fit issue.  Achieving optimum fit smoothed the treble out, improving its tone and realism, while tightening up the low end a fair amount.  Another benefit was the expansion of soundstage from left to right and improving imaging.  I would like to see AKG offer some dual and triple flange tips of the same quality of their single flanges as the changes I heard in sound were significant for me.
 
Other accessories include screw on swappable filters (bass, treble and reference).  The bass filter is basically useless.  It really muddies up the sound, wrecks clarity and timbre and just plain sounds bad.  The treble filter offers a very nice analytical sound that is very reminiscent of the Audio Technica CK10 and is overall more neutral.  The reference filter, which is my preference, slightly pulls back on the treble presence, while adding a very satisfying bass presence.  The build quality of the housings and filters are excellent and beautifully crafted.  I love the smart screw-in mechanism of the filters.  The housings are surprisingly small and tastefully minimalistic in overall design.
 
If there is anything to fault or complain about, it is the cable; in particularly the section of the cable above the Y split.  On the microphone version, there are no strain reliefs around it and I find where the cable enters the strain reliefs on the housings concerning as well.  Perhaps it is unfounded concern but these do appear to be weak points in an otherwise well built and very expensive, top of the line earphone.  I think I would have preferred the upper portion of the cable to be covered in the same nylon feeling material of the bottom portion, allowing for more flexibility without kinking at strain points.
 
Also suspect is the winding case.  While very attractive looking, I find winding the earphone in a large square shape to be impractical and creates odd memory to the cable;  but more importantly the method for storing the housings in the case seems overly complicated and could lead to kinking or damaging the cable, if one is not very carful.  An aftermarket case, like a Pelican, Otterbox or UE hard case is recommended.
 
Enough with the cosmetic and on with the sound.
 
 
 
 
Being that the K3003 is a hybrid design, coherency between the differing driver technologies seems to be one of the biggest concerns; so let me start by saying, to me, it is a non-issue.  I think the driver technologies are blended very well and I did not find anything distracting or disjointed during my listening sessions.  Instruments sounded smooth and cohesive from the bottom of the scale and up, contributing to excellent timbre.  Coherency Schmoeherency.  Just enjoy the music because it sounds damn good from the K3003.
 
 

Coherency Schmoeherency as performed by Van Halen.
 
The treble of the K3003 is simply fantastic, nicely weighted and has a very nice brassiness about it.  It is highly reminiscent of the CK10 treble, albeit a slightly tamed down version of that treble.  With the Meelec trips, I’ve had no issue with undo sibilance or issues with peaks or harshness.  Just airy, brassy and extended goodness.
 
In comparison the Merlin and UM3X treble are much more subdued and laid back.  The UM3X treble is not only more laid back but also sounds less realistic, with less detail retrieval than the K3003.  Upon switching back to the UM3X, it’s takes a moment to readjust, making the UM3X seem a little too dark and smoothed over.  The Merlin treble is also more laid back than the K3003 but is certainly crisper and more present than the UM3X.  Both the Merlin and K3003 high end come across as highly detailed and resolving, especially when amplified with the cleaner signal of the Leckerton UHA-6s mk2, but over all I enjoy the treble presentation of the K3003 more.  It’s the CK10 like brassiness and realism that won me over.
 
The midrange of the K3003 is slightly forward and aggressive with a flavor I would term as sweet. Vocals are very engaging; strings sound lifelike and distortion guitars have excellent bite.  This energetic midrange presentation is right in my wheelhouse of preferences and is one of the most likeable traits of the K3003; in fact I think I’d call the K3003 mildly mid-centric.
 
In comparison to the UM3X, the K3003 displays much greater upper mid presence, which is what gives it the aggressive and sweet sound.  The upper mid of the UM3X is actually scooped out, with more emphasis on the lower mid, giving it a more lush, euphonic or analogue sound.  Both presentations are great but I’d say the balance of upper and lower mid presence gives the K3003 more versatility for a better all rounder and certainly gives it greater clarity.
 
On the other hand, the Merlin seems to split the difference between the mid presentation of the UM3X and K3003.  In my Merlin thread, I compared the similarities between the RE262 mids and the Merlin.  The K3003 mids are more aggressive and sweet sounding than the Merlin still, due to more upper mid presence.  The Merlin gives a more emotional, intimate vocal by being more laid back than the K3003.  I also find the midrange of the Merlin to be more resolving of micro-detail, especially with the Leckerton or Arrow 4g amps.
 
The bass of the K3003 can be summed up a number of ways - fun, satisfying, impactful, deep, textured and musical.  If ultimate neutrality is your goal, you won’t find it with the dynamic bass of the K3003 and the reference filter, although its boost isn’t as large as the overwhelming majority of consumer oriented earphones.  The amount of boost the K3003 offers is quite possibly the perfect amount for my preferences.  It adds realistic and believable weight to strings and keys and I could not detect any issues with bleeding into the midrange.  While certainly not as fast and as accurate as say, the CK10 bass, it is fast for dynamic driver bass and is tastefully colored and very lifelike.
 
In comparison to the UM3X and Merlin, the K3003 has less bass quantity, coming across as the most neutral of the three.  The K3003 beats the UM3X in lower end extension and resolution, while the Merlin has more of its bass focused on deep/sub bass, so it gives the feeling of greater extension and rumble.  With the Meelec trips, the tightness of the K3003 bass competes very well with the Merlin bass, both being some of the tighter dynamic driver bass I’ve heard. 
 
 
 
 
With the stock tips, I thought the K3003 soundstage width was just average to perhaps slightly above average but with a spacious and airy presentation within that soundstage, displaying much better than average depth.  With the Meelec trips, the soundstage is increased from left to right by a substantial margin to my ears.  Comparatively the Merlin soundstage is still wider and deeper but a fair amount taller as well.  The Merlin soundstage is the tallest I’ve heard to date, although with the Meelec trips, the K3003 soundstage is very satisfying.
 
Imaging and separation are as good as the best, or better than I’ve heard in most universals.  Dynamics are also excellent and the K3003 makes a superb low volume listening experience, and is in fact the best I’ve heard yet for low volume.  As mentioned earlier, timbre is very good - strings and keys sound lifelike and believable, with proper note weight; toms and snares snap to life; cymbals and rides have a natural brassiness.  The K3003 is one of better phones for portraying instruments as you would hear them in person.  I would love to be able to compare these to my previous timbre champs, the EX1000 and FX700.  It seems to balance nicely between earphones that come across as too thick or too thin in note.
 
Value
 
While I absolutely love the sound of the K3003, I do find the price point impractical for myself; but I am hoping AKG prices the K3003 more competitively in near future, as other companies release new hybrids and new flagships this winter.  If so, I would definitely be very interested in obtaining my own set.
 
Conclusion
 
If I had to sum up my listening experience with the K3003, I would call it a CK10 with dynamic driver bass.  It takes the same great, brassy treble of the CK10, tones it down just a bit; sweetens up the midrange and lifts it slightly; then adds a more subdued taste of the Merlin bass.  The majority of the music I listen to is distortion guitar driven rock with a healthy does of acoustic/indie/singer-songwriter selections - and it is without reservation that I can say the AKG K3003 rocks; but it does so much more and truly sounds excellent with everything I send its way.
 
Big thanks to Bizkit!
 
Review re-posted here.
 
Comparison with Tralucent 1+2 (9.25.13)
 
Ever since I first had the loaner K3003, I’ve really missed the treble timbre and liveliness that is somehow never harsh.  Every iem I’ve owned, loaned or sampled has had the unenviable task of comparing itself to that memory. 
 
The only real negative I have about the k3k is the cable.  It doesn’t have much in the way, if any at all, for stress relief.  That being said, there are quite a few owners who've had their sets for well over a year and haven't had cable issues, so I finally decided to put that concern behind me and give a second go with the k3k, this time as an owner.
 
The k3k is everything I remember and more.  This time around, for whatever reason, I do not have any issues fitting them properly.  No need for meelec trips, the stock tips are working perfectly.  The housings are small enough to disappear in my ear, with over the ear fit, giving me a pleasing aesthetic, unlike the much larger TG334 or 1+2. (When do the beautiful ladies arrive?)  Also, the k3k has to be the best low volume iem on the market, it’s simply fantastic at low volumes.
 
So I decided to do some comparisons with the 1+2, since its been mentioned they are fairly similar.  While I found they are pretty similar in overall signature, I found the few db’s difference here and there cause quite a large difference in preference, perception and enjoyment.  For my listing I used a combination of the Tera>QS stack and straight from the iPhone 5.
 
Instead of rewriting my notes in paragraph format, I’ll just re-paste them here:
 
K3K
- tiny housings

1. more sub bass presence
2. longer bass decay
3. smoother treble while maintaining liveliness
4. brassier treble tonality; impeccable timbre
5. more vocal intimacy; better emotional connection
6. airy soundstage
7. thicker distortion guitar
8. more acoustic guitar reverb
9. overall thicker note weight

 
1+2
- XL housings

1. leaner bass
2. faster bass
3. hotter / spicier and brighter treble
4. more frequent sibilance
5. vocals placed further back and can lack an emotional connection
6. airier, even grander soundstage
7. awesome distortion guitar bite
8. more precise imaging
9. pianos have great tonality

 
Both are seriously excellent iems and two of the best, as well as two of my favorite iems I’ve ever heard.

Great review, looking forward to the comparison with the MG6Pro. I've been without my Merlin for 2 weeks now as UM sent one of my earpieces in the wrong colour.

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shamrock134 said:

Great review, looking forward to the comparison with the MG6Pro. I've been without my Merlin for 2 weeks now as UM sent one of my earpieces in the wrong colour.

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Yeah, I've heard quite a few people have issues with color and art due to the recent influx of customers from the regional promos.  I hope they get back on track soon.

Thanks for the impressions. Very clearly written.
 
1) How do they compare against the W4, particularly the W4 EQed in the 10-20Hz region? I have the W4 now and EQing them in the sub-bass frequencies makes them super enjoyable, but I can just perceptibly detect bleed and muddying up with the midbass.
 
2) How are they straight out of the iPhone unamped? I suspect my portable listening will be directly out of an iPhone/iPod.

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discombobulation said:

Thanks for the impressions. Very clearly written.
 
1) How do they compare against the W4, particularly the W4 EQed in the 10-20Hz region? I have the W4 now and EQing them in the sub-bass frequencies makes them super enjoyable, but I can just perceptibly detect bleed and muddying up with the midbass.
 
2) How are they straight out of the iPhone unamped? I suspect my portable listening will be directly out of an iPhone/iPod.

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1)  It's been a while since I've owned the W4 but when I did, I greatly enjoyed using the Digizoid Zo with them to obtain sub bass levels that you are probably enjoying through EQ.  For me the biggest difference is in texture and rumble.  Even EQ'd or boosted the W4 bass lacks the lifelike texture and rumble of a dynamic driver.  It gets close and does sound very good but that was the main reason I sold the W4.  Otherwise it is a superb universal and I absolutely love its treble.
 
2)  The Merlin sounds great straight from the iPhone.  That and the nano 6g without additional amping is how I mainly use them.  Since the Merlin is tuned towards my preferences, I do not feel any need for EQ or boosting of any sort.  Plug and play!
 
Edit: I should add that output impedance of the iPhone 4 is less than 1 ohm and the Nano 6g is 2.

Great review as always. It was really nice that you included the possible impedance issue with amps. Looking forward to your Merlin vs MG6pro comparison.

Shotgunshane,
 
Excellent review! One thing I really liked about it is that not only did you put your mind to it, but your heart in it, too -- that is rare. This is an informative and very nicely written piece. Although you did use a few bits of audio jargon, it was very nice to see you did not abuse it. Nor did your review become far too complex to keep up with or exceedingly long. As you 'progress' with your reviews, think that perhaps there isn't that much you need to improve. Once again, well done!

Thanks for the write up. What are your thoughts in comparison to the ASG-1?

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whitefroded said:

Thanks for the write up. What are your thoughts on comparison to the ASG-1?

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I posted a very quick a/b of the two in the Aurisonics thread that you can find HERE.  The Merlin is definitely a couple of steps up but the ASG-1, providing you like the surround effect it gives, is a very fine universal and I'd say worthy of top tier status.
 

Quote:

shotgunshane said:

1)  It's been a while since I've owned the W4 but when I did, I greatly enjoyed using the Digizoid Zo with them to obtain sub bass levels that you are probably enjoying through EQ.  For me the biggest difference is in texture and rumble.  Even EQ'd or boosted the W4 bass lacks the lifelike texture and rumble of a dynamic driver.  It gets close and does sound very good but that was the main reason I sold the W4.  Otherwise it is a superb universal and I absolutely love its treble.
 
2)  The Merlin sounds great straight from the iPhone.  That and the nano 6g without additional amping is how I mainly use them.  Since the Merlin is tuned towards my preferences, I do not feel any need for EQ or boosting of any sort.  Plug and play!
 
Edit: I should add that output impedance of the iPhone 4 is less than 1 ohm and the Nano 6g is 2.

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Thanks a lot for your input. I am seriously leaning towards the UM Merlin after perusing the main thread, in addition to reading your impressions.
 
Instead of springing for the Zo, I might as well go for the next level IEM and have one less thing to carry around.
 
I was completely content with the W4, until I heard the bass texture on the GR07 that I bought for my dad. Sure, it wasn't as precise as the W4, but it was just such an ineffable difference in presentation and, ultimately, enjoyment that it had my ears craving the W4 with that kind of impact in the low end.
 
One more question - obviously everyone is talking about the bass, but briefly, how do the other frequencies compare to the W4? Are the mids more recessed? Do the trebles lack the shimmer of the W4? Those are my only two concerns coming from the W4 .

Quote:

discombobulation said:

Thanks a lot for your input. I am seriously leaning towards the UM Merlin after perusing the main thread, in addition to reading your impressions.
 
Instead of springing for the Zo, I might as well go for the next level IEM and have one less thing to carry around.
 
I was completely content with the W4, until I heard the bass texture on the GR07 that I bought for my dad. Sure, it wasn't as precise as the W4, but it was just such an ineffable difference in presentation and, ultimately, enjoyment that it had my ears craving the W4 with that kind of impact in the low end.
 
One more question - obviously everyone is talking about the bass, but briefly, how do the other frequencies compare to the W4? Are the mids more recessed? Do the trebles lack the shimmer of the W4? Those are my only two concerns coming from the W4

.

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I know exactly what you're talking about comparing the GR07 bass to the W4.
 
No, the mids aren't recessed at all.  They are very comparable to the RE262, which has the best mids I've heard in a universal.  I loved the intimacy of the W4 mids, they were just lacking some clarity and transparency.  The treble on the W4 is weightier and the treble on the Merlin is lighter, crisper and airier.  Both are very well done.