The Kennerton Gjallarhorn Modified

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100+ Head-Fier
Decent Headphones, Terrible Price
Pros: Very comfortable, wide sound stage, roomy pads
Cons: Extremely microphonic spring-steel frame, microphonics from the stock and 3rd-party cables, muddy mids, zero bass impact, poor isolation.
This morning I got in the last pair of Kennerton Gjallarhorn GH50 JM Edition that Audio46 had in stock. Ignoring the pretty nice packaging, I want to dig straight into the headphones themselves.

I listened to a variety of music on these (classical, opera, rock, pop, hip-hop, dubstep) for about a couple hours. Many will say this is not enough time to really get a "feel" for headphones -- what with burn-in, etc. However there's no amount of burn-in that will fix the issues present in these headphones.

First let's talk about microphonics and isolation. When I'm looking at a pair of closed-back headphones, I'm looking to close my ears off from the outside world as much as possible -- within reason of course, since these aren't IEMs. Unfortunately the level of isolation is comparable to many semi-open headphones like the E-Mu Teaks I have sitting next to me. To make matters worse, both the stock cable and a nice 3rd-party cable I have transmit every single tiny rub and tap of the cable against my hoodie directly into my ears. This wasn't noticeable when I had the volume at ear-piercing levels, but any sort of casual listening levels led to constant interruption.

Now let's talk about sound quality. Another thing I expect from closed-back headphones is good bass impact. I want to /feel/ the bass, not just hear it. Unfortunately, these simply do not deliver. While there is good clarity and reproduction of most sound under ~300hz, it's just... thin. Again comparing to my E-Mu Teaks, the experience is substantially better in a $500 pair of headphones -- about 1/3 the price. On the other hand, vocals are stellar on the Gjallarhorns -- both male and female. That is until they're drowned out by the muddiest reproduction of mid-range percussion I've ever heard on a pair of headphones over $300. Snares have zero texture, and horn instruments sound like they're being played behind a shower curtain in an NYC apartment bathroom.

All that said... they're very comfortable, have a nice wide sound stage, and the pads are very roomy. But that's all I can say that's good about them.
John Massaria
Fair enough if you don't like them, but saying that they got no bass is nonsense. Those are one of the most dynamic headphones I've ever tried, and I've tried a bunch...
No need for burn in or any of that audiophile myths. They slam really hard out of the box if the seal is good.
John Massaria
John Massaria
He likes what he likes Vmoda for example and maybe his gh50 was dropped and damaged who knows
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John Massaria

Member of the Trade: JM Audio Editions/Headphone Modifications
Pros: Everything sounds amazing since the mod, perfect now for any genre of music, customizable bass tuning now, the mids and treble are pinpoint perfect above the Magni, they sound very wide and open like open backs (but they are closed backs)
Cons: I have only the stock cable I dislike, they are large headphones (50mm drivers for ultra dynamics), they do need some work on metal band to get tight fit (bend it inward as I mentioned in first review), you need to mod them for them to achieve this insane level of bliss

I will probably add to this review as things progress- but I since did a review for the Russian made Kennerton Magni vs Gjallarhorn - but everything about the Gjallarhorn has changed. I was never really loving the sound even after I bent the metal bands for a tighter fit around my ears- the sound got better- but it was always too different and departed from a sound I really could love love love like the Magni. I love the Magni headphones - they are in many ways better than my Sen HD600 - and they are a closed back headphone - which is what I need. The problem with most closed backs is they sound closed in- and that's where the Ghorn was suppose to sound more open and more dynamic with less wattage to bring out micro details - similar to real horn speakers. The thing is- I am really hyper sensitive to timing and notes ending when they should, lingering on when they should and knowing when to vibrate a bit- I am very sensitive to this with speakers and very sensitive to this with IEMs with multi driver armatures - if the timing is wrong when it comes to the blend of highs mids and lows- I will hear it right away.

Anyway- I will make this very very brief for now- as I said I may add more latter. I did two things to the Gjallarhorn's that have transformed them into nearly perfect sounding headphones for me.

I do not recommend this unless you want to void your warranty with Kennerton- but if done correctly you should be fine. Do not attempt this or hold me or Kennerton liable for these mods- please.

1) I removed ear pads to gain access to the alen wrench screws- I removed the 4 screws.


Removed the font and back leather plate on outside of earphone. I accessed two holes - See picture-


I removed the carpet on both sides- and cut them as plugs- bass plugs for the ports. See next picture where one bass port is covered and the other is open- you can pick how you want your bass to playback- both sealed, one open one closed, or both open. The more air entering the port the more bass. I find two open ports too much bass. One open and one closed is perfect for me.

The Next HUGE upgrade and this has everything to do with the now pinpoint stop start of vocals and instruments is this-

This is the normal driver configuration on the Kennerton web site

All I did was this:

GH50 mod.jpg

I added furniture dots - they key here is DO NOT go anywhere near Graphene Mylar membrane- you will break it easily if you touch it. The next key is the dots have to be super small and soft and fluffy not Velcro types they are too dense and don't work well. Please do not ask me which exact dots I used- I used the ones in this picture finally deciding these have the best sound. I used 10 dots on each ear horn cup. Be careful not to go higher than flat edge on top or you may have a lumpy cover when you put the screws back on.

Re-assemble everything back. Now you are ready.


That's all. I never thought that the transformation would be as big as it is, but it is. These are now my favorite headphones of all time period. They were always extremely efficient to drive as Kennerton designed them from the factory. But now modded they are pinpoint accurate and create the stop start to vocals and instruments I have always craved in headphones. They are faster than anything I ever heard for headphones. The closest thing I can compare them to is a recording studio I went to many times before. The studio is owned by one of the most fanatical people I have ever met- and I am super grateful for it since he and my recording engineer friends have taught me so much back then. As an example of how well researched and crazy this studio owner is- when he built The Music Palace (Mix Palace), for his ground on the special audio electrical circuit breaker box he used a thick bundle of individual stranded pure copper rods of over 1" thick each that was set deep inside the ground by a water well company - the cable reaches way over 100ft into the earth. He built the studio with special power transformers that the electrical company brought in special for his specifications that are on the poles outside the studio. The entire studio is wired so all lighting and non musical equipment is on on one side of the building and the other side is wired using only the musical wire when possible intersecting at right angles. The main mixing room is completely isolated- I won't go into how they did it- but it is way over the top crazy isolation - ceiling, floor etc. The speakers are what we are talking about - and comparing these modded Ghorns to- speakers in The Mix Palace; they use a set of horn Kinoshita 4V large monitors mounted in 8 tons of concrete! If you ever want pinpoint stop start perfect sound- this is the place that literally had me crying on how perfect the sound was. I really did shed tears on how gorgeous the sound moved me.


I have never heard a headphone come close to this sound as much as the Kennerton modded Gjallarhorn. I can't grasp that this type of dynamic headphone does so much right and so little wrong. Beyond the best sound I ever heard in any IEM, ANY headphone or even most speakers systems.

Bass extension is customizable as mentioned above. I prefer one hole covered and one open. I don't need to EQ anything- the sound is as recorded from the source. Vocalists like Chris Issac or Alison Krauss, Bjork, Bob Dylan, Billie Holiday etc all sound excellent as an example. Deep voiced recordings where the recording engineer wanted intimate sound with the singer and the listener like Jane Monheit, Tori Amos or Sarah McLachlan all sound as close to perfection as they should. From crazy electronic music like the Gesaffelstein or The Crystal Method to rock such as Van Halen to Muse all sound insanely great here as well. What don't these headphones do? They aren't bloated they aren't sibilant, they are pinpoint accurate, sound warm, mids all sound right, high end detail is all there without fatigue AT ALL. The stage is huge- the placement on the stage is pinpoint.
The only limit here is the recording quality.

I know so many people are going to doubt the sincerity of this review mod, but I can't explain it better than wholly sh$t balls this is the best dam headphone I ever heard bar none. Of all the trade shows like Cam jam and AV Shows like T.H.E... no kidding... And for all the naysayer's- well I can tell you- you haven't heard these modded yet have you?

I know this review will garnish a ton of doubt... I could care less. I am always truthful and passionate about music and equipment. I don't know what else to write so I will stop here.


UPDATED 8/31/20- too many people asking what size the fluffy dots are or their name- this is all I can supply at this time- the name I do not have (sorry about that) - I would think a hobby or home goods store would have similar sizes and make sure they are fluffy material - good luck and happy listening- I LOVE MY Modded Gjallarhorn GH50s and wouldn't sell them or trade them- they are that good- I hope you can hear them some day...

not this kind of fluffy...


SOME PEOPLE HAVE BEEN ASKING for what kind of felt to use-
It needs to be flexible thin but fluffy- something like this:
THEY NEED TO BE THIN FLUFFY AND FLEXIBLE without a hard bottom- they need to flex and not be too big-





I am not sure if Kennerton did the mod with the very thin or thicker fluffy dots- its import to use thin flexible dots- and I am not sure if he did BASS mod of two ports on each side BUT here is what Kennerton wrote back-

Hello John,
I just finished testing your Gjallarhorn modding option. Yes! It works well!
The 1st measurement results are in the attachments.
What did I find out what did I feel? First, this mod gives a slight peak in the area of 5 kHz. This is a very interesting peak.
It is a small rise in this register that gives a very characteristic feature of sound delivery, which is often able to cause even a Wow Effect. And this is great! After all, music should give only positive emotions and joy!

The second point is a small dip of 200-500 Hz. This is also not bad because it is in this range that there are often sounds that can be described by the word "nasal", it is in this range that the rise causes a feeling of hum and dirt.

But the main point is quite a noticeable rise (500-1000 Hz) in the most important range - Upper Midrange! It is this moment that allows me to enjoy female vocals, especially impressive are Сontralto (165-692 Hz), Mezzo-Soprano (220-880 Hz), Soprano (262-1000 Hz).
It is in this range that all the charm of solo violins, solo guitars, flute, piano, vocals are found. Music that lacks these frequencies is usually called "boring" or "dark". And percussion, in general, is almost completely audible only in this range ( 400-1000 Hz).

That's why I'm thrilled with your experiment. I repeated it and I can say YES! THIS IS GREAT! I would also like to note that the greatest positive effect was when connected the headphones to a tube or hybrid amplifiers. This was much more effective and interesting than when connected to transistor amplifiers.

UPDATE 10/18/20) Kennerton now calling the modified edition the JM Edition in honor of the mod- and it will be available to purchase soon... I should also mention I do not work for Kennerton but would one day sure love to if they offered me a job- I believe in their products that strongly. I make no monies from my reviews or moddifications whats so ever - ... I do it for the love and music and nothing more...



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John Massaria
John Massaria
The design of the un modded horn allowed a delay in decay of music and notes extending reverb- the mod stiffens up reverb so it no longer an issue of standing waves
It creates a pin point accuracy in notes not found in any other hp I have used and by opening up on port for bass is icing on the cake for more fun balance

Late to this party, but just came upon this mod as I was preparing to sell these phones. They just didn't do it for me for the same reasons you noted. Right now I'm using them in my portable rig with a Woo Audio WA8. Best sound ever from a portable rig.

Thanks for creating this simple mod.

Best, Joe
John Massaria


John Massaria

Member of the Trade: JM Audio Editions/Headphone Modifications
I understand Kennerton is working on testing mods and making an actual model with these mods available so it will be under warranty- of course expect the price to be double lol -JK


100+ Head-Fier
I have already one, and hope not to purchase another brand new one modded, I cannot buy a new headphone every two months...


New Head-Fier
Please help some of you. I need to calculate values for 10 band parametric PEQ equalizer for Gjallarhorn GH50 Jm. Here is a link to a page on how to do it, but I couldn't do it. I welcome any advice.