Kennerton Gallahorn GH50 JM Edition Horn Graphine Closed Back

General Information

Graphene-coated multilayered composite

Driver Unit
50 mm

Frequency Response
10-50000 Hz

116 dB

33 Ohm

Maximum Input Power
250 mW

Cord length
High quality 2 meters length detachable cable made from OFC wires is terminated with high quality gold plated 6.3 mm TRS connector

406 g ( w/o cable)

JM Edition is an acoustic modification of Gjallarhorn headphones, which was made by John Massaria, one of the first owners of Gjallarhorns.

Gjallarhorn JM Edition Limited Special Request Color Karelian Birch Indigo Blue

Custom Edition Added 6-19-21 Can Be Arranged By Special Order
Hybrid All Leather Ear Pads with Suede That Touches The Skin- No Perforated Holes.
Indigo Dark Blue/Gray Stabilized. Karelian Birch- Custom Rognir Head Band Added.


Kennerton Audio
Address 11, Lomanaya st., Saint-Petersburg, Russia, 196084
Phone +7(812) 9203680

Latest reviews


1000+ Head-Fier
Kennerton Gjallarhorn GH 50 JM Edition v2 Review
Pros: VERY strong bass
Good overall sound
Very comfortable
Good Price
Cons: VERY strong bass
Smaller soundstage
Not quite TOTL clarity and detail
Low-end can overwhelm everything else without bass plugs
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Edited 05 Jan 2022: New Burson Conductor 3XP DAC/AMP changed the sound profile and got rid of some of the sibilances on the highs (but not all) while decreasing the overall bass for a more balanced profile. This makes the headphones an overall smoother listen than my Schiit did. I also have no issues with the bass and sibilance on a portable Fiio FC3 DAC for some reason, so it may be source dependent. I've tried the GHJM with both cables and the rougher highs (Across the Burren is painful)/boosted lows persist on a desktop amp. These work great for me as a portable solution, but not a desktop headphone. I have a pair of the JM Audio XTC-Closed (XTC-C) on the way, I will update with how those sound vs these.

I’ve had the Kennerton Gjallarhorn GH 50 JM Edition v2 (GHJM) for a little while now and I finally have the chance to write a review. These are the Blue Stabilized Maple version that you can’t even get directly from Kennerton as far as I can tell. The Baltic Sea version is more Blue/Green and are a lighter color than the dark blue of the stabilized maple. You can also only buy the Gjallarhorn GH 50 JM Edition v1 from Kennerton. The v2 edition must be sent to JM (@John Massaria) to get him to install the JM Proprietary Fractal Fiberglass Mesh Technology (TM) and some different sets of earpads. I am also using his balanced JM Audio 4-pin XLR cable, which provides great sound and is EASILY driven from my Schiit at ¼ power. From the cable, they receive power and conversion from a Schiit Bifrost 2/64 DAC and a Jotunheim 2 amp (both excellent Schiit btw). They are being sourced through my desktop PC with a Moon Audio Silver Dragon (what a waste of money) cable pulling from Tidal Hifi Plus. I picked these up directly from John, to replace my Focal Celestee (which my wife stole and won’t give back) as a closed-back set to compliment my Rosson RAD-0. I will be comparing these to the RAD-0, Focal Utopia, and Hifiman HE-1000 v2 (HEKv2) as well.

GHJM Side.jpg

Build Quality/Comfort:

Man, I love how these feel, especially with JM’s fluffy earpads. Everyone says that they have an industrial look to them thanks to the wood and metal and leather, but I consider them to be more medieval than anything else. The headband with its crown-shaped leather and buttons makes me feel like a Jester in a king’s court. The stabilized maple is gorgeous and sturdy, but a little darker than I would like because it covers up a lot of the beauty of the wood that shows up on the Baltic Sea edition. Nonetheless, these are beautiful and well-made headphones. The GHJM is also extremely light and comfortable – around 400g. My only complaint in this category is that over time, the earcups start to sag and I have to push them back up – slightly stronger springs from Kennerton would solve this issue.

GHJM Left.jpg


OK, so while I’ve owned a lot of high-end headphones, including the Meze Empyrean and Focal Utopia 2020, that doesn’t mean that I can pick apart sound like a professional reviewer. On the plus side, neither can most other people, and it makes for a boring read, so below are MY impressions on the sound – deal with it or go write your own review. I will list the song I use to test certain aspects of headphones and you can find my headphone test tracks playlist in my sig if you want to try your own headphones to compare. Also, I don’t have an accurate way to differentiate between mids and highs (most people don’t, can you really tell where vocals cross from mids to highs without measurement?), so I prefer to list specific instruments and vocals and let you judge.


These are hands-down the bassiest headphones I’ve ever heard. If you are in the market for a bassy, closed-back headphone, just stop reading and buy these now – you will not be disappointed. I will start this review without the bass plugs in just for you, but it’s not my preference as I am NOT a basshead (I hate the people who pull their car up next to me so they can rattle my car in time with theirs.) By the way, the plugs actually decrease bass, not increase it like I thought they would. Also, I am using the fluffy JM pads. The Knife’s “Silent Shout” just really accentuates how bassy these headphones are. The mid-bass just kicks so hard, and you can REALLY feel the sub-bass. That said, this overwhelms almost every other part of the song, the vocals and synths are drowned out by overwhelming bass. Once, again, if that’s your thing, there ya go. That’s the theme with the plugs out for every song, so I’m going to put the plugs back in. Starting “Silent Shout” over and now there’s still a ton of good, thumpy bass, but it doesn’t overwhelm the vocals as much and the synths come through much clearer.

David Guetta’s “I’m Good (Blue)” has some intense drums at the beginning and the GHJM highlight that. Once the sub-synth comes in, the reverb is so strong that you can feel it in your body. The vocals and high-synth are clear and sound very detailed. The drums do begin to drown the mid-synth out when they come back in though. Cyberpunk 2077’s “I Really Want to Stay at Your House” is another phenomenal sound to test these out in the lows. The bass has a ton of impact starting around 1:00 and it'll blow your mind quite a bit. This is where these headphones really excel. That said, the RAD-0 has less bass, but it is cleaner, less distorted, and more detailed – but, the RAD-0 feels like it's missing pieces of the bass as well that the GHJM definitely isn’t missing.

GHJM Right.jpg

Instruments and vocals:

The Greatest Showman’s “The Greatest Show” shows that the vocals need a little work - I use the intro whispered vocals to test vocal clarity and there are points where it is hard to understand what Hugh Jackman is saying. High-pitched vocals are a little screechy at parts during the song too. Skillet’s “Stars” has some great low-end to start with, but it drowns out the mids a bit. Once the low-end fades away a bit, the vocals come through strong, but more muted and less detailed that the RAD-0. The snare drum and hi-hats are also more muted. It still sounds better than most headphones in this price range, especially closed ones, but these are the weaknesses of these headphones. High-pitched female vocals from “Stars” can also be grating or just missing altogether, once again highlighting the primary weakness in these headphones.

John Legend’s “All of me” highlights the lows again but does allow the vocals and piano to shine through. The vocals manage to overwhelm the piano a bit and the low portion can still overwhelm a bit. That said, it still sounds really good and if you listen to mostly bassy music, but want to jam out to some good vocals every once in a while, these can do it. I do have to warn you that the high notes in this song can sound shrill and harsh when he hits them. Some punk rock like Something Corporate’s “Hurricane” sounds great with the guitars hitting hard, excellent reverb, good drums and bass that don’t overwhelm, and great vocals. The piano solo that starts at 2:15 sounds really clear and isn’t overwhelming when the drums come in. Fireflight’s “For Those Who Wait” is another good example of the high-pitched female vocals being a bit harsh. So, great bass, good mids, sharp/fatiguing highs on some songs with very high notes.

GHJM Top.jpg


The RAD-0 does not have the issues with vocals being screechy or hard to understand that the GHJM has. The RAD-0 is missing parts of the bass that the GHJM highlights – parts I didn’t even realize were missing until I got these. The Utopia and HEKv2 don’t have anywhere near this level of bass and are likely missing parts of the bass too since I got the RAD-0 because it does a better job of presenting clean, impactful, and detailed bass. The RAD-0 has better instrumental presentation, vocals, guitars, classical instruments, and a better soundstage, though the GHJM has a surprisingly good soundstage for closed-back headphones (thanks to JM’s v2 upgrade). Keep in mind, I’m comparing these to open-back TOTL headphones that cost at least $1,000 more. So, the GHJM holds its own quite well compared to most closed-back headphones and is likely one of the best short of the Stellia or DCAs.

But, guess what? The XTC-C is better in every way. JM Audio has essentially outdone itself by using their own beryllium drivers instead of the Kennerton horn drivers. The XTC-C has less bass, but it's cleaner, tighter, and slightly less in quantity. The XTC-C has better mids and highs that are not harsh at all. I prefer the XTC-C to the GHJM for every genre of music - and it's cheaper for now. The GHJM is however better than the Sony MDR-Z1R - with similar bass (plugs in, with plugs out the GHJM has more,) better mids, and less sibilant highs than the Sony. The Sony is still a great headphone, but when we're comparing TOTL headphones, any apparent weakness has to be called out.

GHJM Back.jpg


These are a great companion to my RAD-0 and work surprisingly well as mobile headphones powered by my HiBy FC3 phone DAC/amp. If you read all the crap I wrote above, then you already get it. These are basshead headphones, but also a good set of mid/top-tier closed-back headphones. They aren’t as good as the $2600+ pair of open-back RAD-0s, which is all I have as a comparison right now, but they are still really good headphones or I wouldn’t be keeping them. They could be endgame headphones for the right person at far less than TOTL prices. I mean, do you need to pay 2x as much for a Stellia? No, unless you really want smooth highs and perfect details, especially since those have their own set of issues. If these seem like your cup of tea, contact @John Massaria and order a pair or order some XTC-Cs (the regular colors of the GHJM are cheaper and easier to get, you can also send in an existing pair for the v2 mod).

Headphone Scoring - Each category can be split into quarter points:
Build Quality
Ear Pads / Tips
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I'll be trying GH50 JM v1 soon(they don't seem to sound too impressive), and will probably order an XTC Open! Been hearing really good things about XTC. I find it curious how he is able to sell HiFiMan(and Audeze?) headbands with his headphones... He must be an authorized HiFiMan product reseller & modder? This is also a curious statement, "layers of fiberglass shaped similar to a Fibonacci like pattern that make the image and sound stage sound much larger than even open backs". And the odd $0.02 price reductions..? :thinking:

Just to nit-pick, the information re-statements are kind of awkward:
"XTC-C has less bass, but it's cleaner, tighter, and slightly less in quantity"
"the vocals come through strong, but more muted and less detailed"

I don't think this rating system is logical, either. Sound quality shouldn't be mixed with box contents and comfort, so if we separated Sound Quality and Everything Else, we get scores of 2.5/3 and 6.75/7.
Great, thanks. I was aiming for z1r. I tried them and liked them, but you are
saying that xtc c are better than ghjm , and ghjm are better than z1r?
Could you in a few words compare xtc c to z1r for me? Thank you!


500+ Head-Fier
Kennerton Gjallarhorn GH50 JM MK2
Pros: Sound Stage is unbeaten by any closed back in the sub $2500 range
Cons: Warmish sound signature might not be for everyone
Isolation may be lacking for a closed back headphone
Sent my Kennerton Gjallarhorn JM Editions into @John Massaria, the guy who designed the original JM for Kennerton, to give them the full upgrade to the JM Edition MK2. Here is his website:

The mod really just awakens these headphones. Basically it takes everything about the headphones and turns it up to 11, bass gets turned to 11.5-12. Everything is just a little bigger and bolder with more snap and punch behind it. The Headphones are still a little

The mod takes the already stellar sound stage of the JM and makes it even big with out adding any hollowness/airiness to the sound. I would say the MK2 might even be getting into the HD800/Rognir sound stage range, especially if you are using the fuzzy pads John sells. The sound stage is at its most impressive during live recordings. It is almost like you are sitting in the audience and the band in playing in front of you and you pick out where each instrument is one the stage. I can not over state how incredible the sound stage is on these headphones. Not just for a closed back but even for the $1700(for the stabilized wood version $1500 for non stabilized wood version) John is selling them for ($175 for the mod if you already own the Gjallerhorn GH50/JM.)

I have yet to find a sound that these headphones couldn't handle. Never once I have I noticed any details missing or any song feeling crowded or congested like what can happen with some closed back headphones. Every detail is exactly where it should be nothing is missing from any song.

The highs are super clean and pleasant. Cymbals and percussion really have a fantastic and snap followed by a great ring/sizzle that is not fatiguing or lacking in any way. I can't imagine anyone would find the highs lacking or under developed.

Bass is one of the main things that is changed on the mod. The bass is just as tight and controlled as the stock JM but it adds more impact and power behind it. With out adding so much that it becomes over bearing or bloated. There is no bleed into the mids and It also slightly increases the bass speed and its accuracy with in the sound stage. I could see that some people might find the bass to be a little to powerful especially if you are comping from a headphone like the HD800s or any highs focused headphones. Just give your ears some time to adjust and you will find that the bass is the perfect mix of power and control.

The mids are lush and silky giving the headphones a warm and comforting sound that is hard to beat when it comes to long listening sessions.

Plugging the bass ports really brings the bass power down from a 12 to more like 10.5.

With the bass ports unplugged the bass in really front and center and the star of the show. It is just so impressive and fun that you tend to lose track of everything else because you are too busy jamming out to music.

With the ports plugged everything else gets a chance to shine. It lets the highs and sound stage get more of the attention while the bass play backup in a very pleasant non intrusive way.

Adding the ports almost makes the MK2 a 2-for-1 headphone with how drastically it changes the primary focus of the sound.

The only real complaint I have is that adding the bass port does slightly remove some of the isolation on the headphones allowing a little more outside noise to get in than over the stock JM.

Looking from the out side you can see that he changed a couple of things over the stock JM Editions. He removed the black felt covering the driver and replaced the Driver guard with a 3D printed mesh diffusion grid. So you do have to be careful not to get any dust or dirt into the drivers if you are using the stock pads. He added a Bass port on the back that can be plugged to reduce the bass. Looking into the bass port you can see that he added the same 3D mess to the back of the driver and changed the the dampening to his own custom material.

You can really tell that the MK2 is what the JM Edition is meant to be.

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Nice, a lot of information that's actually useful. Thank you for your review and thank John M. for his creative mind. :smile_phones:
BTW, thanks for the link, pretty cool website one I will utilize one day...


100+ Head-Fier
Kennerton Gjallarhorn "JM Edition" - A triumph for innovation, a victory of concept design.
Pros: - Elegant, tight, perfectly distributed bass.
- Outstanding timbre and dynamism rendition.
- Accuracy: notes stop and start when they should, which creates an incredibly realistic sound, specially in live recordings.
- Soundstage and depth unheard of in closed-back cans. Music meant to be played in big theaters or audiences in general is unbeatable (classical, some jazz recordings, soundtracks, etc…).
- Perfect balance between detail and musicality. Instrument separation is unreal, yet it never ends up being too analytical.
- Vocals: Quoting John Massaria “liquid, intimate when recordings call for it, wet when recordings reveal such wetness”. And throwing in my two cents: explosive & vibrant when recordings call for it as well, such as in soprano and operatic voices in general.
- Unique, non fatiguing, immersive, addictive sound signature.
- Comfortable for long periods, (upgraded soft ear pads made of lambskin).
- Aesthetically gorgeous: heirloom wood finish, hand-crafted, laser engraved logo.
Cons: - First and foremost: YOU HAVE TO BEND THE METAL BAND to get a tight and comfortable fit for the proper, intended sound. The horn design is very sensitive to headphones head position, so having such a clamp is a MUST to get their true sound. Bending the metal band is a tedious task that should be done with certain precautions (using both hands, all cables detached…) but do not bend it shyly or otherwise you won’t get the perfect fit. Once it’s done it’ll last forever -see review
- Supplied cable is useless (even though it’s indeed very high quality) if you don’t have a 6.3mm headphone adapter (and I don’t even recommend those because they are prone to destroy jack outputs).
- Microphonic headband if touched while wearing (which happens very rarely but still…).
- Highly recommended break-in (burn-in) of 75-120 hours in order to have an optimal sound reference.
- Revealing when it comes to bad recordings. If there is an imperfection you will almost certainly notice it straight away.
- May lack frontal impact for some genres intended to punch you in the face. - see review.
- Mids can be "funny" in mid-range rich music. I think they go hand in hand with the uniqueness of the JM horns sound signature (depth - some instruments sounding more distant than others for example) but some people may think otherwise... - see review

From the author’s web page: JM Edition is an acoustic modification of Gjallarhorn headphones, which was made by John Massaria, one of the first owners of Gjallarhorns. We considered it quite worth to be a separate model and now we are offering you the official Kennerton workshop version of it.
You can read in depth about the modifiacion from the first hand, from the author himself.
The main differences touched the bullhorn form and change of phase inverter. It did significantly changed the accent of the sound of the headphones without dropping any quality at all.
We named the model after the author, JM Edition.

Since the main goal of this review is to talk about the sound I will not go into detail about the design and development process. You can read about that in Kennerton’s web here (trust me, the graphene membrane technology and the horn specs, among other things, are interesting things to read).


Also, I want to mention that from this point on I will refer to these cans as the JM horns.

I will say though that aesthetically these are one of the most beautiful headphones I’ve ever seen. Their wooden finish, leather pads and Kennerton’s logo metal pin on each side make them so beautiful that everyone around you will notice sooner or later.

For the purpose of this review I used a Sony NW-WM1Z (Modded) as source (balanced output), the JM horns were connected through a 4.4mm balanced OCC cable and all music was played in FLAC (default for this review) (I will specify bitrates and bitdepths when necessary) and Native DSD (will specify). I always aim to keep the audio chain as short as possible so no amp or “middle chain” devices, just source and headphones.


Let’s start then. So, what do we get when we buy the JM horns apart from the headphones. Well, we get a very nice, genuine leather case, a high quality cable with 3.5 mm rhodium plated connectors and gold plated 6.3 trs connector and a strap to comfortably carrying the case. I’ve used the leather case (strapped) to carry the JM horns and my DAP (Sony NW-WM1Z) and I can say everything fits perfectly. There are two inner pockets where I can store the DAP and a set of cables separately and then put in the headphones, and everything feels safe and sound.

The stock cables are a bit useless unless you have a 6.3mm to 3.5mm (or 4.4mm, or whatever you use) adapter and I really missed the option to choose a different cable or to have an adapter included. I ordered an Audiocrast HIFI 8 cores 7N OCC cable from AliExpress and I couldn’t be happier with it.

The first thing I noticed out of the box was how comfortable these headphones were, yet the clamp wasn’t great and they tended to move up and down too much, which generated a kind of inconsistent sound. I found myself re-adjusting the cans too often and it became a bit problematic. That’s when I realized how important is to bend the metal band just like John Massaria specified in his review. At first I went a bit shy on the bending and I did not like the results I was getting, then I went too strong and the clamp was too hard. It was a tedious task and it took me about 2 hours of different bending angles to find the sweet spot, but once I found it was pure bliss sonically and comfort wise.


The bend should be done with both hands simultaneously, pulling inward at the same time shylessly. Repeat the operation on both sides. Test the clamp and re-bend outward/inward to find the right spot.

The cans are weighted at 406gr, but once you find the right clamp they’ll feel lighter than that. I can now wear them for 4 hours non-stop with no problems.


This is how my JM horns look right now. A bit crazy, but it’s a must for all sound related purposes.

Speaking of the sound, out of the box the cans sounded a little bit bright and bass-shy, and the midrange was weird in a funny way, yet I was already blown by the depth and soundstage, simply unheard before in closed back cans. I then proceeded to the burn-in process. I burnt them for 20 hours before testing them again, and I kept doing the same thing for 4 times until they reached the 80 hours mark. I reckon the most significant change happened around the 60hr mark, where something just clicked in my head. It could be placebo, it could be the adaptation process but at that mark everything started to sound cohesive and unique in an incredible way. Before, I wasn’t fond of some midrange sounds, such as snare drums (which sounded a bit muffled and kind of distant for my taste), but from the 60hr mark my mind changed completely. Everything started to sound so good that when I went back to my Shure 1540’s (very precious headphones to me) I just could not believe the difference. In some genres (rock, metal and pop) the Shures were sounding kind of lifeless and flat now… really flat. And when it came to classical music the Shures sounded just bad! That was an inflection point. The JM horns had completely won me over.

It’s from this point I started to review the sound seriously and everything from now on is written with the sound I got after the 80hr burn-in mark in mind and the metal band bent perfectly, which is key for the purpose of optimal, perfect sound.

Before delving deeper into the sonic aspects I should mention here that the JM horns are extremely easy to drive. At just 33 Ohms of impendance you can plug them pretty much anywhere and they will be easily crankable and enjoyable. You don’t really need an amp with these, which is a pro in my book.

Soundstage, imaging and depth

When we think about closed back cans we imagine good bass response, good noise isolation and hard impact. Well, the horns have arrived to completely change the game. We still get good bass response (perfect, actually) and good noise isolation but we trade a bit of that front impact for great soundstage and imaging, and incredible depth. It’s the first thing I loved about the JM horns. It caught me completely by surprise because I was just not expecting that level of layering and separation from a closed back. Music recorded in small halls, chamber music and music where the soundwaves hit walls sooner is reproduced with such realism you won’t believe it. The combination of the pinpoint, perfect timing of notes, the reverb, the soundstage and the depth makes you easily imagine where the instruments are being played, their size and how big is the hall, theater, club or whatever the place. Other types of music like metal and rock also benefit from this in different ways. For example fast drumming or percussive tracks that use stereo imaging are very, very pleasant to hear with the JM horns. This all comes without any significant loss in musicality. Actually this sound signature is very immersive in its own, unique way. If you feel analytical you will easily be able to do analytic listening given the excellent instrument separation, but should you change your approach and decide to just enjoy the music, you will be able to do that as easy. Carefully mastered and produced recordings such as anything Steven Wilson’s hands touch will sound sublime with the JM horns, but I will close this chapter warning everyone that having this amount of detail, layering and separation comes at the cost of noticing bad recordings straight away. If a recording is poorly done you will certainly notice.

This is the perfect scenario for the JM horns to do their magic.

Let’s talk about bass, midrange and treble response now. I don’t judge sound based on graphs and numbers. That’s all interesting tech talk but in the end the most important thing for me is how I feel when I close my eyes and listen to the music. How far can these headphones take my mind? Do I feel like I’m in the audience? Does the singer sound like if he/she in my room?! Do I feel the bass or is it just overreaching and distorted? Can I hear and feel the electricity coming from the electric guitar? Those are some of the instinctive questions that look for an answer when I listen to music, so let’s go for it:


The first thing I noticed about bass was its elegant, perfect separation, tightness and detail. We live in a day and age where bass is often played exaggerated and overblown to a point it’s just completely distorted. Many people can’t “feel” the bass anymore unless it’s completely overblown, and I really dislike that. The way the JM horns cast bass is simply perfect for my taste. It’s the most naturally realistic bass I’ve ever heard. For example, when I was listening to Vivaldi’s ‘L’estate Presto’ by Rachel Podger [DSD] and the violoncello entered the scene it sounded EXACTLY like a real violoncello. Also on Miles Davis’s “Bitches Brew” [DSD] the bass line is perfectly heard, tight, with each pluck discernible from the next. It’s the type of bass that you feel in your body not by distortion or loudness, but by it’s extended, natural frequency. You feel it’s huge and you know the size of the instrument it’s coming from. Truth be told, string instruments in general are simply fantastic on the JM Horns. I don’t know if it’s the nature of the wooden horned acoustic chamber but they sound so real it’s unbelievable. When we move to electronic music bass the low frequiencies keep its qualities. In Die Antwoord’s ‘Pitbull Terrier’ or Igorrr’s ‘Hollow Tree’ for example the bass is huge and tight when it hits, you feel it all over, but it’s not in your face. You are not next to the huge rave speaker, but in the second row, and that’s something you should be ready to expect. These headphones are elegant and never punch you in the face. They don’t want “blood on your hands” or ears, they want you to feel and see everything, from the size of the instruments to the width and depth of the stage, so they take you one or two rows back to give you the whole picture. You keep feeling the impact but in a different way. At first I did not know what to think of this but now I simply can’t go back to the front line, “I want to keep driving the Mercedes

instead of the Monster Truck”

and I’ve found out I’m more comfortable sitting a few meters back from the front line of the jazz club,

cup of wine in hand, enjoying the bigger picture. Atmospheric music with huge bass gets the best of the horns. Soundtracks specially are end-game level with the JM horns. Take Star Wars III ‘Anakin vs Obi Wan’ [24 bit], every time the bass enters in the scene I get goosebumps. Trust me when I tell you things can get really huge and immersive with the JM horns if the music calls for it. My friend was so moved by the horns performance with the Star Wars OST that he assured it was like hearing it in a big theater again. Now take a bass heavy metal album like Sunn O)))’s ‘Monoliths and Dimensions’, well, it sounds like I feel it was intended to sound; Like being played from a huge, deep, dark cave in the center of the earth. The “twisting, creaking wood” sounds on the first track are creepier and unnerving than ever. A completely cathartic experience. Of course all of this should give you an idea of how great they are for epic/fantasy/action movies/videogames... I could keep talking about the bass section but I don’t want my review to reach biblical proportions (I’ll fail anyway…) so I’ll leave it here. I hope I have made myself clear so you have an approximate idea of what to expect. Summing it up, the bass is perfection for those who like natural, tight, extended bass that's felt for all of those qualities and nothing else.


Midrange on the JM horns is the most debatable aspect of their sound signature.
Depending on the type of music, mids can be close to perfection or weird in a funny, totally enjoyable way. Igor Boitsov’s review aimed most of its criticism to the mids, calling them out for being uneven. I can totally see why. When I started the sound tests I remember I experienced a problem with the mid-range similar to what he describes as “some mid-range sounds heard as if from a distance” and “some mid-range instruments give the impression of a low-frequency component removed from their sounding”. The second problem was fixed when the clamp was good (remember to bend the metal band like Beckham!, a step which I think Boitsov’s skipped judging by the pictures of his review).

Now for the first problem, I remember that perception improved with the correct clamp as well. It was only noticeable in busy midrange music, where two or more instruments are “competing” for protagonism along the same range of frequencies, and after listening to the JM horns for so many hours I don’t know if that “problem” is part of the amazing depth they are able to create, to the extent I barely “hear” it anymore, or maybe I just don’t care, at this point I don’t know. I am well aware Dire Straits ‘S/T’ album sounds a little bit different now. The midrange sounds deeper and sometimes more distanced in the vocals department, but I really like it. In my mind it just makes sense for the music to gain that layering and separation. It creates a livelier sound that may decrease the perceived “warmness” of some records. It happened to me while listening to one of my fav prog rock albums of the last decade, Opeth’s ‘Pale Communion’. It’s a mid-range rich album and it sounded more detailed, deep and separated than what I was accustomed to. At first I found it a bit weird but repeated listens made me appreciate things I wouldn’t have been able to appreciate if I had not listened to it through the JM horns. It’s definitely a different listening experience for sure for mid-range rich music. When the mid-range is more focused and controlled and there is no battle for the attention spot these cans manage to deliver things with a delicate, yet full bodied taste. They somehow read the intended atmosphere of the recording and reproduce it. This is specially palatable in the vocals area. Listening to Becca Stevens sing in Ambrose Akinmusire’s ‘Our Basement’ [24bit/96khz], from his masterpiece , ‘The imagined saviour is far easier to paint’, is the perfect example for this. The chorus vocals remain back in the sides giving Becca’s sweet voice the attention spot. Paraphrasing John Massaria, vocals are “liquid, intimate when recordings call for it, wet when recordings reveal such wetness”. If you close your eyes with Johnny Cash’s ‘American IV’ you’ll be surprised to “see” Johnny playing for you in your room, for real. JM Horns cast the best reproduction of Johnny’s voice I’ve ever heard, goosebumps all over the place. So, what happens with explosive, vibrant voices then? Well, the JM horns are great playing them as well. Listening to Simone Simons in Epica’s ‘The Divine Conspiracy’ I heard a vibrance, and timbre in her voice I had not ever heard before. That album in general sounds outstanding because, let me tell you, the horns were made to play epic symphonic arrangements. Not to anyone’s surprise brass instruments (specially instruments) sound just like they were meant to sound. And mixing them with ‘epicness’ (like in soundtracks) is the perfect combo for the horns to shine. When it comes to heavy brass jazz the horns shine, specially in live recordings, but be warned once again, do not expect to be in the front line and hearing the trumpet right in front of you, the JM horns will take you to a table a bit behind in the jazz cafe to enjoy the show from a safe distance. John Coltrane’s ‘Blue Train’ [DSD] sounds just like it’s being played exactly from that distance. When it comes to more energic and aggressive music such as rock and metal (favorite genres of mine by the way) the JM horns perform great in the mid-range section. The layering and depth makes artists with “big sounding” productions (lots of guitar reverb, echoing and such effects) sound HUGE, like if playing in a huge festival stage with no crowd, which makes the sound travel freely and clean. Sometimes I also imagine myself witnessing the band playing in a huge studio. It’s truly an immersive experience. Rush’s ‘Moving Pictures’ or Devin Townsend’s masterpiece, ‘Ocean Machine’ are the first examples that come to my mind. Then with genres such as death or black metal you will soon realize that, without the JM horns, your death metal is suddenly not coming from the catacombs anymore

and black metal will lose its windy coldness

or its dungeon like aura,


and do not get me started on how the JM horns work with prog/tech death metal... I completely rediscovered albums like Dead Congregation’s ‘Grave of the Archangels’ or Deathspell Omega’s ‘Si Monvmentvm Reqvires, Circvmspice’ (specially when the Gregorian chant comes at the mid section of ‘Carnal Malefactor’, the atmosphere was so greatly improved I got lost in it, again proving that human voices are read perfectly by the JM horns). For the first time ever I was able to discern everything in Defeated Sanity’s ‘Passages Into Deformity’ and keep enjoying it. Alkaloid’s ‘Rise of the Cephalopods’, which is one my favorite metal songs ever, gets to a whole new dimension with the JM horns. Aggressive electric guitar genres like Thrash Metal and Metalcore sound awesome too. Guitar lines are delivered fast, vibrant, tight and with perfect precision. Slayer’s ‘Reign in Blood’ invites you to raise the volume and enjoy the hell out of every single wave of electricity coming from its guitar tracks. Besides, the horns makes the rock of bands such as U2 or Oasis shine in all of their glory. Flamenco is another genre that gets the blessing of the JM horns to sound as good as it gets, transporting you next to the ‘tablao’ to enjoy its intricate guitar melodies and vibrant ‘cante’. Listening to Paco de Lucía and Camarón de la Isla joining forces in ‘Como el agua’ is greatly improved by the horns, giving it a very colorful, live and vibrant vibe that is really hard to beat. Summing it all up, the midrange will possibly be the most disputed aspect of the JM horns. It’s influence vary from genre to genre and even from song to song in some cases, but in my experience it’s never a deal breaking experience, on the contrary I feel it makes a lot sense given its peculiar sound signature. In the end it will be up to each person to decide if they like it or not, but I think it wouldn’t ever be a decisive hindrance.


Usually I don’t pay much attention to treble, but I consider its qualities to be fundamental for a headphone to sound good. If it’s not worked on properly certain treble problems can be an instant no for me.
I usually like a treble that is present enough to give a natural, lively sound without going too much into the bright side of the force. I also hate treble shy sound signatures, they sound really unnatural to my ears and ruin everything else for me, so I was really, really pleased when I found that the treble of the JM horns felt actually close to perfect. I’m in absolute love with the hi-hats and cymbals sound, which are heavy in the genres I listen to the most (rock and metal). Also the kind of high frequency sound from percussive hits and clangs from objects such as kitchen cutlery hitting plates and sounds of that sort is so real it’s almost scary. It’s the kind of realistic treble reproduction that could pass for a real object noise in the room you are. Again, the pinpoint precision of the reverb and echo is key to reach this level of detail. Miles Davis “Sketches of Spain” [DSD] treble dynamics completely passed the test with the JM horns, which made the album sound totally alive! I also did the What Hi-Fi treble test and I was really glad to hear the JM horns passed it with not a single problem. I also realized during this test how amazing the piano sounds with the horns as well (that Keith Jarrett’s track sounded absolutely fabulous!). There seems to be a peak at 11khz mentioned in Igor Boitsov’s review. I went on and tested the material he provided to proof his point, but after testing the same material with two other pair of headphones I came to the conclusion that it was more of a recording problem than a JM horns treble frequency response peak one. So all in all I give the treble a close to perfect score. It makes everything sound spacious and lively without ending up too airy sounding. I’ll repeat now that due to its treble, along with depth and separation, the JM horns will lift the warmness veil from some recordings. These recordings won’t sound bad at all but they will surely sound a bit different and more live-like. To get finished, the excellent treble reproduction is just the icing on the cake for these cans, period.



The Kennerton Gjallarhorns “JM Edition” are a triumph for innovation, a victory of concept design.
It’s not easy to design headphones based on a new, never seen before concept, and Kennerton have not only succeeded, they have surpassed all expectations with these cans, creating one of the best sounding headphones ever. I’m right now on John Massaria’s train, these are the best sounding headphones I’ve ever heard and they have the King’s crown for me. I think we’ll be seeing more horned headphones designs very soon, but these Kennerton’s Gjallarhorn cans will always be in the history books as the proud, marvelous sounding pioneers of that concept.
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Hi, did you tried the Magni? I want to buy a closed back headphone and I listen to mostly death/ technical death metal/ progressive death metal. You can answer me in a PM. Thank you!
Well guys, after almost a year since I wrote this review I thought I would say something! First of all, I'm still rocking the hell out of these cans, they are still my fav headphones ever (I spend a lot of time listening to music so the burn in count is well over 6000 hours now haha!). As I have stated before I don't feel I need anything else anymore. I'm set up for life (as long as my device and cans stay alive haha, but I take very good care of both so...). Everytime I try other headphones I miss some aspect of the sound signature of the JM horns. They are that good imho ladies and gentleman. The aspect that still captivates me the most is the spacious, huge studio like sound despite being closed back cans. It's simply mindblowing. Music is just a different experience with these. Hope you all are still enjoying them aswell.


John Massaria

Member of the Trade: JM Audio Editions/Headphone Modifications
It is an honor to write and review my own honorary modified version of this headphone. Originally I was one of the first owners of the GH50 and decided to enhance it by tweaking it- and it impressed me so much I declared it my favorite headphone no matter the type; over the ear, planar, electrostatic or IEM and at any price. I did the mod innocently- and was amazed when Kennerton contacted me that they were going to test and possibly release this version as a full production model. Well here it is. I make no money at all from the sale of this headphone, I do not work for Kennerton - I review and modify for a hobby out of the passion I have for the love of music. That is my reward.


100+ Head-Fier
First impressions out of the box:
They come in a very beautiful genuine leather case. The warranty is enveloped very nicely and the overall presentation is awesome. The stock cable is very high quality, yet I really missed a headphone adapter to plug them right after the unboxing process (since it's got a 6.3 mm TRS connector). The cans themselves are handcrafted and they are a sight to behold. Really unique design that catches immediately the eye. The first pleasant surprise was how comfortable they were. They weight 400gr but once on the head they feel really light. The lamb skin earpads are warm and comfortable and I could spend 2+ hours with them in the first session with no problems. Moving onto the sound:
Incredibly open sound for a closed back. Unheard til this moment in closed back cans. But what really got me was the depth of these. Out of the box I could not believe my ears. The soundstage is wide and impressive but the depth is simply out of this world. They sound very clean and with a sense of accuracy that's just pinpoint perfect. Moving to the frequency response, the bass section is close to perfect for me, the mids are dense in a very special way, classical music is pure bliss with these (the only thing I'm not fond of for now is the snare drums sound, but it could very well be because of my present-day source, which is not very good). I have not paid close atention to treble for now, and I gotta burn them for at least 75+ hours before I can make a complete opinion, but for now these are very unique and impressive headphones.

I'm updating after gettin a bit better source and 20 hours of burning (waiting for my 1Z to arrive):
First, these headphones are truly unique... Their sound signature is so weird yet so good that it's kind of difficult to find the correct words to describe them. I'll just say that their sinergy with jazz music is the best I've ever come across. In general, well done classical and jazz live recordings sound just perfect with the Gjallarhorns. There is something unique about the way they cast the bass and mids. The instrument separation is phenomenal and the depth is, again, out of this world for a closed back. The instruments have real, full bodies and everything sounds how it's supposed to. I'm still adapting to their signature for metal and rock, specially when it comes to the snare drums. They sound very different to every other drum part, like pushed back and a bit muffled (wet). Truth be told, I like in your face, punchy, dry snare drums and maybe it's just a preconceived preference thing. I'll update once I've burnt them for a bit longer and have my 1Z back.

50+ hours of burning now. The more I listen to these cans the more I like them. The adaptation process was not easy for pummeling and energetic genres, but now I just can't listen to music the same way I used to. These, guys, are a really really good headphones. I'm starting to get some things written about their sound signature:

- Their combination of great depth (unreal layering), soundstage and horned design make them sound like a surround system! I realized this when I was listening to some soundtracks. They transported me to a surround cinema. Everything sounded immense, huge, and it did not lose any detail in the process, the bass is clean, big, yet not boomy. Sounds COME from all directions. And that's a thing, they create this weird illusion where THE MUSIC COMES TO YOU. It loses a bit of impact/punch, which may be weird at first, but once you get used to it you just can't look back. It's a very unique sound signature and let me tell you, very very addictive. Classical and jazz music has never sounded this good on headphones, seriously. If you like live quality classical and jazz recordings these horns will get a very emotional response from you without any doubt. There is plenty of room for every instrument to breath and you will know how big is the string instrument being played.

- Now for fast and aggresive music listeners... Give these horns time (and follow the 72+ hours burn-in recommendation). They may sound really weird at first, but then you will be impressed and... addicted. Other headphones will start to sound flat in comparison, and I mean REALLY FLAT. This may not be such a bad thing for most black & thrash metal or hard rock, but you will soon realize that without the horns death metal suddenly is not being played in a real catacombs. Atmospheric black will lose its windy coldness, and do not get me started on how these work with prog metal... Also the horns make rock from bands such as U2 shine in all of its glory

- They are unforgiving of poor recordings. If the music was poorly recorded you will notice... Creating such a space between every instrument has these "cons"...

Can't wait to pair them with my 1Z and hopefully I'll be able to complete the recommended burn-in time before "the glorious marriage".

John Massaria

Member of the Trade: JM Audio Editions/Headphone Modifications
Awesome review- which color did you get? What country are you in and how long did it take you to get the GH50 JM Edition? Thanks again for your review- I hope more people publish their thoughts -


100+ Head-Fier
I got the dusk color. I live in Spain and they took 4 days to arrive from Russia via UPS. The only bad news were the custom fees, which were crazy expensive. Thank you John for your passion and appreciation thread.


Headphoneus Supremus
Do the G-horn and G-horn JM edition both have a cooler tonality and brighter treble than Magni ?


Headphoneus Supremus
And does anyone know the wood the lighter and darker G-horns have ?


Headphoneus Supremus
I just received a Raspberry Jam JM today. Man they are way better looking in person than the pics. I will sit down and listen tomorrow. Cant wait.

John Massaria

Member of the Trade: JM Audio Editions/Headphone Modifications
Lohb -They are both warm beautiful sounding hp's - The Ghorn needs less volume since it's a horn type that makes the driver mouch more efficienct so some people may turn them up too much but I suggest low and slow volume adjustments with the Gjallarhorn
- I do a comparison here on Magni vs GH50 Unmodded and then modded in another review and then finally a review of the JM edition (my fav of any hp of any price or type) - but start here-


Headphoneus Supremus
The Indigo Blue will have to wait till Monday Evening. But I can post the Reds! I cannot see how to upload pics here. I will post them in the general Kennerton Thread right now.


Headphoneus Supremus
Nice, I heard the new wood was about to be released...just wish I knew which wood they are using on the Dusk and light...might be Ash ?