100+ Head-Fier
Dekoni Blue
Pros: Great looks
Well made
Effortless to listen to
Very comfortable
Fostex T50RP heritage
Good soundstage
Cons: Not a final word when it comes to detail and resolution
Packaging is very basic
Cable is just decent
Very touch competition

Dekoni Blue is a modification of the Fostex T50RP MK3, which is the only mod of this model officially approved by Fostex. The price is set at $299, but right now you can get them for $249.


Dekoni has been around for quite some time now, offering the best aftermarket earpads on the market. Then an idea came – let’s create something different than the earpads – and that’s how the Blue came to life.

As I said in the beginning, this is the only modification of T50RP that has been officially approved by Fostex.




The unboxing experience of the Dekoni Blue is very simple and modest. All you’ll find is the box, headphones, and the cable with an adapter. The box is pretty ordinary, but it has a great color and cool esthetics, making it a good looking addition for your shelf.
I really can’t say anything else, this is very basic and gets the job done, but don’t expect a fascinating experience while getting these out of the box.


The cable included in the box is 2m long and it has a 6.3mm jack connector, but you’re getting a 3.5mm adapter in the box. The plug going into the headphones is an angled connector with a locking mechanism. While it’s great for security, it is too hard to unplug. You basically have to pull the cable really hard, which may cause problems in the long-term, so I recommend not to unplug the cable too often.

Other than that, it’s a pretty ordinary, black and rather thick cable that is not great, but not terrible either. It gets the job done, doesn’t really get in the way, but it surely won’t impress anybody.


The cable is pretty standard.

Build quality and comfort​

As you should have expected from Dekoni – the earpads are absolutely stunning.

Now into some great things – these are fantastically made. I’m digging the blue color of the earcups, with that contrasty orange “Fostex” written on the headband.
Even though the majority of the headphone is made of plastic, it feels robust and very reliable. If you’re looking for a pair of headphones that you won’t have to really care about, I don’t think you can find anything significantly better.

As far as comfort is concerned – these are some of the most comfortable closed-back headphones I’ve ever used in my life. The included Elite hybrid earpads are super plushy, superb to the touch and quite simply the best earpads included with a pair of headphones ever. Dekoni is known for their earpads, so this shouldn’t really surprise anybody.

The Blue is not the lightest headphone around, nor it is the heaviest, but I find the weight to be just right. Clamping force is moderate to strong out of the box, but thanks to those extraordinary earpads it only helps with a great and secure fit, not causing any problems with the comfort whatsoever.




Dekoni Blue is a modified Fostex T50RP MK3, and it’s a true modification, rather than completely changing the original. What’s changed you’ll ask?

For sure the first that you can see is the changed design, with that gorgeous blue color on the earcups. I believe that it’s a great change from a rather boring and plain original.
Other than that, the only two things that have been changed are the earpads and the inner baffle being redesigned. As far as the earpads go, you know my opinion already – these are absolutely mind-blowing.
The inner baffle on the other hand has been changed to switch the tonality a bit, creating a more personalized headphone by Dekoni.



Studio heritage, made for an effortless experience.

I’ll start this part by saying, that if you’re looking for an absolutely best all-rounder and the best bang for your buck headphone in this price range, Dekoni Blue definitely isn’t that. In terms of raw technical performance and being universally tuned, the Hifiman Deva is a much better product for you.

The bass is definitely the star of the show, and you’ll hear it from the first moment. It’s big, rounded and very forward. Bassheads are going to be quite pleased, but I strongly recommend plugging those into a strong amplifier, as it helps to tighten up the low frequencies a lot. Other than that, the bass is addictive, strong and just fun to listen to, but nowhere natural or neutral. Put some Post Malone or any electronic music into them though, and you’ll be in for a treat.
What’s surprised me the most, was that the bass is more reminiscent of a dynamic driver construction, providing a great punch and physicality, which is rather rare for planar magnetic headphones.


Fostex T50RP has been around for a while now.

The midrange is yet again – very pleasing. It is warm, lush and smooth with a hint of energy in the higher region. Thanks to that, these are great for long listening sessions, where you’ll really appreciate the fantastic comfort and this very smooth, easy tone of the Blue.
While not the most detailed pair of headphones out there (well, not even close to being close), those are great to just sit, relax and listen to some music without paying too much attention to what you’re hearing. I tend to reach out for them after listening to my Hifiman Ananda, which is a detail monster, with a much more focus on the classic “audiophile” qualities in music.

The treble is yet again rather smooth and clean, with just a touch of spiciness to it. While I won’t describe the Blue as dark sounding, it is noticeably calmer and less detailed than any of my other headphones. That makes it a great companion for long listening sessions once again.
Don’t get me wrong though – these are not muffled. The treble region focuses more on a smooth and pleasing approach with a moderate detail retrieval, but I won’t call it withdrawn by any means. There’s still sparkliness to it, and there’s actually one thing that the Dekoni Blue is great at – recreating the timbre of the cymbals. They somehow can easily reproduce this thick, bold and rich sound that is fast and clean at the same time – that’s impressive.


I absolutely love the color.

The soundstage is quite surprising actually. While being narrow and condensed, it has an impressive depth to it with excellent imaging. The fact that it’s narrow isn’t really weird – it’s a closed-back headphone at the end of the day. But it’s a rather interesting feeling, having all the sounds really close to you when left and right is concerned, with a really good depth towards you.
Of course, it doesn’t sound as open and airy as open-back offerings, but having only closed-back headphones in mind, I’d actually call the Blue’s soundstage great.

To summarize – Dekoni Blue is a great secondary headphone to have in your arsenal. While it’s not universal when it comes to tuning, it provides a fun, fatigue-free and very comfortable listening experience that is easy to appreciate.



Dekoni Blue is easy to like, and it won’t kill your wallet.

The legend is alive. Dekoni Blue is a very good modification of the vastly popular T50RP by Fostex, providing a great build quality, comfort, and that smooth, easy tone. If you have a good, neutral open-back headphone for your daily use but you’re looking for a secondary pair that’ll give you a chill and easy time with your music, the Dekoni Blue is a good choice.

Gear used during this review for the sake of comparison and as an accompanying equipment:
  • Headphones – Hifiman Ananda, Hifiman HE400i 2020, Hifiman Deva, AKG K501, Audeze LCD3
  • Sources– Cayin N3Pro, Cayin N6ii, JDSLabs Atom stack, SMSL SU-9 + SH-9, Feliks Audio Echo MK II
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100+ Head-Fier
I'm blue da ba dee da ba daa (Da ba dee da ba daa, da ba dee da ba daa, da ba dee da ba daa)
Pros: Build quality
Fatigue-free and fun
Built upon base model of T50RP MK3, which means the modding freedom is unlimited (spare pars market too)
Cons: Some may find it lacking in bass definition - however, if you have a stronger amplifier, the bass should be more defined

Now, the following are neither pros, nor cons, they are aspects that may or may not be what you are looking for:
Warm sound signature, V-shaped sound signature
If you have been following the headphone scene back in 2018, then you are probably familiar with the Dekoni Blue. Fostex’s T50RP is probably the most modded headphone model in history, and Dekoni took part of that as well.

Dekoni originally announced their partnership with Fostex back in May, 2018, however, the headphone was actually previewed way back in February. It would go on to gain its biggest audience from Massdrop (now Drop). The Blue has been released at several different price points and variants - since its release, the prices varied from $170 - $300. The original offering at Massdrop (Drop) included a set of extra Elite Velour pads.

However, what makes Dekoni’s Blue model different from the other modded T50RP MK3’s is the fact that it’s an official partnership with Fostex. What this essentially means is that Fostex directly manufactures the Blue model for Dekoni Audio. I believe this is the first and only official partnership that Fostex made for the T50RP MK3 - all the other well known mods were done by the company selling them, this includes: Mr. Speakers’ (Dan Clark Audio) “Mad Dog” and “Alpha Dog”, “Argon” by Mod House, Cascadia Audio’s “Talos”, and Mayflower Electronic’s T50RP mods, and others.


Unboxing experience

The unboxing experience is quite straight to the point - a nicely designed (and matching blue) cardboard box, and headphones wrapped in bubble wrap inside. I would best describe the contents and the whole presentation as minimal - just as you would expect from a Fostex T50RP.

Formal format of what you get inside (this may depend on what variant you are buying, this is the stock one):
1x Dekoni Blue headphone (with Elite Hybrid earpads)
1x 2m cable (6.3mm jack)
1x 3.5mm adaptor


Build quality

Originally aimed for studio use, the Fostex T50RP was made to be lightweight and durable - something that can be worn without much weight to it, while also withstanding regular wear. Since Dekoni used the T50RP MKIII as its base model, it follows the very same characteristics as the original.

Starting from the top, the headband is made of high quality faux leather. It offers an exceptional amount of padding (I will cover the headband in more detail in the “Comfort” section), and is also stitched along the edges - which will ensure that there is no peeling at the edges.

Moving further down, the headband is screwed in place to a plastic piece, and right below it is another plastic piece that holds the height adjustment sliders. Both of these parts are made of high quality plastic.
Now, you may notice that Dekoni Blue shares many things with the Fostex T50RP MK3, and this is because it uses the T50RP MK3 as its base model excluding the ear-pads, which Dekoni replaced with their high quality Elite Hybrid pads, everything is basically the same.

This means that the Blue features the same metal height adjustment sliders, the same lock-mechanism for the cable connector, and the same exposed braided cables.

Speaking of the cable, it’s my least favorite part. I am personally not very impressed with the quality of it. Unfortunately, it’s no different than many headphone cables today. Anybody who has seen me on forums knows how much I brag about the quality of Sennheiser HD598’s cable. That is mainly because it is what I perceive as the standard of what a rubber cable should feel like.

The stock cable is impossible to store away. I usually tie cables around my hand and push the plug through the center - essentially tying the cable and leaving it as a “circle”. However, this is impossible to do. with the Blue’s stock cable… The cable keeps returning to its original shape and turns into a whole mess. This essentially means that you will have two meters of cable just hanging out there… which isn’t ideal. Another issue that comes with the stubborn nature of this cable is that the connector in the lock mechanism can get pushed up.



Like the name suggests - the Blue’s main design characteristic is the authentic Dekoni blue. This essentially makes it stand out from the original black and orange aesthetic. Dekoni Blue is anything but bland - it features branding on several places. The first thing you will notice is the big “Dekoni” branding on top of the headband - the printing is of high quality and is printed on top of the headband’s faux leather.

While Dekoni didn’t change the Fostex logo on the sides, they did change the printing on the ear-cups and the color of the height adjustment sliders.

It’s no secret that the T50RP has held its authentic design ever since it was first implemented. The 1st generation of the T50 series actually featured a round ear-cup design, and it wouldn’t be until the 2nd generation that Fostex would introduce the now iconic design - round ear-cup base with an elevated square at the back. Ever since the 2nd generation, Fostex has remained the iconic design of the RP-series.

In terms of the actual color-scheme, Fostex only introduced the black and orange color combination with the 3rd generation. Of course, the main cosmetic difference that Dekoni made was the color-scheme. The height adjustment sliders were changed from the original silver finish to a black finish. In similar fashion, instead of the classic “T50RP” label and Fostex’s RP logo on the ear-cups, Dekoni changed it up - it features Dekoni Audio’s logo, large “Blue” label” and a visual of a sound wave.

Dekoni Blue keeps the same good old design with minor aesthetic changes.



Comfort being Dekoni’s main focus field, it’s not surprising that it’s one of the main selling points of this headphone.
The headband itself has light cushioning - and this is something that may or may not be a problem. I myself don’t have any problems or discomfort with it, and that’s mainly due to the fact that my hair acts as a cushion between the headband and my head. However, if you are bald, this may be something that can present a problem.

And of course, the highlight of this headphone - the pads. Dekoni Blue has Dekoni’s most premium series - the Elite Hybrid. This series utilizes sheepskin on the outside, velour on the face, and fenestrated (perforated) sheepskin on the inside of the pads. The general ideology of this combination is as follows:
The sheepskin on the outside is mean the provide better isolation and a better lower frequency response. The velour on the face is meant to provide a breathability and comfort, while letting the sound signature to be more open by letting sound travel through it. Finally, the fenestrated sheepskin on the inside is meant to let the sound travel through it and essentially “enter” the ear-pads themselves - this results to a more open sound and also gives better breathability.

To put things into better perspective, let’s talk about how they handle long listening sessions. At no surprise, the Blue didn’t show any signs of discomfort - even after listening sessions that consisted of several albums and multiple hours of music. In fact, it was rather my incapability to stay seated in one place that caused me to take a break and walk around. The ear-pads did not get warm or sweaty, and there also weren’t any hotspots. The velour material is very comfortable and pleasant to the skin - it reminds me of a very soft and cozy sweater. However, Dekoni Blue is not one of those headphones that disappears on your head, you are aware of it at all times.

The clamp force is neither too strong, nor too weak. What is important to me is that the headphone can stay in place while I move around. Generally there are two types of people:
Those who enjoy sitting back in a chair and dissolve in the music, and those who tend to live the music and move around. I am the latter type, I like to move my head and dance around, that’s just how I enjoy music. This being said, I am happy that the clamp force could keep them on my head, and that I didn’t have to lift them up every two minutes.

Dekoni Audio being a company that specializes in producing ear-pads, the comfort aspect is one of the main focus fields. Even if you find yourself unhappy with the headband, the spare parts market for the T50RP is so wide that you will have no problem finding one that will suit you - this basically goes for everything regarding this headphone.

History of planar-magnetic headphones & the important role that Fostex played in it

Fostex RP has a very interesting history, and it has a lot to do the technology used. While manufacturers like Audeze and Hifiman were making planar-magnetic (isodynamic/orthodynamic) headphones in high-end market, Fostex focused on producing affordable planar-magnetic headphones - that’s essentially where it found its potential.

Being more curious about the widely unknown history of Fostex’s RP range, I found out that Fostex is given very little credit for its importance in the planar-magnetic field. After some hours of digging into the history of planar-magnetic headphones, I was barely able to source the first ever planar-magnetic headphone. Surprisingly enough, in 1972 Wharfedale produced the world’s first planar-magnetic headphone: the Wharfedale ID1. Who would’ve thought that a manufacturer like Wharfedale, a company that is most well known for their speakers, produced the world’s first planar magnetic set of headphones.

Wharfedale ID1

After that, I had a difficult time tracking down exactly which models were released between 1972 and later, however, I did find some notable information:

1974/1975 - Fostex launches its T50v0 model - making it the world’s second planar-magnetic headphone. It would only be sold until 1976 - the v0 series is generally less documented. From my research, the only headphone in the v0 series was the T50v0 - making it the first T50 from Fostex.

Fostex T50v0

The T50v0 would lead Fostex to become an OEM for other companies, and produce headphone models that are based off of the T50v0. These models would be:

- NAD RP18 (it had two variations of the drivers: mylar diaphragm, and the kapton diaphragm)

Nad RP18

- Aiwa HP-500

Aiwa HP-500

- Sansui SS100


- Audio Technica launches its first headphone series - the AT-700 series.
*I cannot confirm whether the AT-700 series featured planar-magnetic technology, but I did find information that Audio Technica was among other manufacturers who were involved in the planar magnetic headphone market

- Yamaha launches its first planar-magnetic headphone: the HP-1. The HP-1 was designed by the well known Mario Bellini. Yamaha was apparently doing far better than other manufacturers in terms of sales for their orthodynamic headphones. This is mainly due to the fact that they utilized efficient marketing and follow-up series

Yamaha HP-1

Yamaha followed up with the following models:

1978 - YH-1000

Yamaha YH-1000

- YH-100

Yamaha line-up (middle - YH-100)

Yamaha YH-1 (left), Yamaha YH-100 (middle), Yamaha YH-1000 (right)

- YHD-1

Yamaha YHD-1

Mid 70’s
- YH1
Yamaha YH-1

- Fostex launches T10, T20, T30, and the T50 models (v1) - notable feature of the 1st generation were the round ear-cups & ear-pads, and round driver

Fostex 1st Generation

- Bang & Olufsen releases the U70 - designed by B&O’s well famed designer Jacob Jensen


- Fostex finally introduces its Regular Phase (RP) technology (v2) - notable feature of the 2nd generation was the change of the ear-cup construction and the headband. This generation introduced the rubber headband and also started featuring the iconic “RP” logo on the ear-cups.

Fostex T20RP v2

Fostex T40RP

- Fostex launches T20RP MK2, T40RP MK2, T50RP - notable feature of the third generation was the change to a square-shaped driver. This would be a significant change, as though it completely changed the sound signature, but also all future models would implement the square-shaped driver. This generation followed the same rubber headband as the previous one.

Fostex T20RP MK2

All of this being said, there’s no doubt that there were several planar-magnetic headphones in the early years. However most of them didn’t see much success - mainly due to the difficult process of manufacturing these headphones, it wasn’t cost efficient for the manufacturers.
This is why Fostex played a major role in the planar magnetic field. Besides Yamaha, it truly brought the planar-magnetic technology to the commercial market. Fostex’s RP series was widely used in studios, that’s how it raised to fame.
You can also notice that most of the early planar-magnetic headphones were produced for a limited time - meaning that many companies decided to leave the field of planar-magnetic headphones.

The most interesting part is that Fostex was founded in 1973, which is only a year or two prior to the release of the T50v0. Nowadays, names like Hifiman and Audeze are the ones that people generally associate with “planar-magnetic”, however those companies were founded more than three decades later - Hifiman in 2003, Audeze in 2008 - making Fostex one of the first companies to seriously step in the planar-magnetic headphone market.


If there is anything that the Dekoni Blue is recognized for, it’s the lower frequency response. While I didn’t have a chance to hear the original Fostex T50RP MK3, I can definitely say that Dekoni’s marketing was pretty accurate - the overall sound signature is leaning toward the warm side of the spectrum.



One of the biggest misconceptions about the Blue, is that it’s a basshead headphone. I personally wouldn’t agree with this, and it’s definitely something that I saw many people referring to. Let’s go to the roots, what does “basshead” mean? I would consider “basshead” to be a headphone that can deliver sub-bass rumble, has tight punch and powerful impact delivery, and overall have a “controlled” bass.

“Why So Serious?” by Hans Zimmer is one of my standard testing tracks for sub-frequency response and sub-bass rumble. The dark track from Zimmer’s masterpiece score for The Dark Knight has several points where you can hear the deep low frequencies, however, it is around the 3:26 minute mark where there is a drop. During this drop you should be hearing sub-bass rumble pulsating.
While Dekoni Blue is capable of reproducing the sub-frequency tone, it doesn’t rumble.

“Had Some Drinks” by Two Feet is a track where you can clearly test how the headphone holds up with both bass quantity and sub-bass rumble. There is no question about the Blue filling space with sound (quantity), however, it doesn’t rumble. I will later explain why I think this is, and it has much more to do with the technical nature of the T50RP, rather than the sound signature.

M.O.O.N’s eponymous EP is a very enjoyable electronic album. The third track, “Hydrogen”, is the one that puts both the quality and definition to the test. The kick should remain clean and tight - the Blue rather represents it with more quantity and less definition. The kick has more presence and thus isn’t tight, it “takes up” more space in the mix.

In similar fashion, “Smoking Mirrors” by Lee Curtiss, should remain a clean beat. Although the clap isn’t in sync at all times, there are parts where the clap meets the kick, and this results to a clean uniform impact. However, Blue lets the kick go on even when the clap meets the kick, this is what I would refer to as “slow decay”.

One particular album where I enjoyed this type of bass response is “Music to listen to….” (too long album title) by Bring Me The Horizon.

The low region is definitely different from what I have heard up until this point. It is a bass response that has more presence, but doesn’t have much definition (doesn’t have tight punch and as powerful impact/delivery). The lower frequencies usually fill the mix with bass presence, this “takes up” more space in the mix. Another thing is that the Dekoni Blue definitely doesn’t rumble (unless turnt up to extreme volumes), here is why this is - if you ever saw a T50RP driver, you know that it is square-shaped and not of a very large size. This small sized speaker driver has limited capability to deliver these low frequencies, whereas larger planar-magnetic headphones (Hifiman, Audeze, Rosson Audio, Abyss, etc.) have the advantage of extended lower frequency response.



The mid-range is best described as warm - the exact quality Dekoni was going for in terms of tonality in this model.
“Forget Her” by Jeff Buckley, a track that is leaning towards the brighter side, is a perfect one to listen for sibilance or piercing peaks. This can particularly be heard when Jeff hits the “s” or “sh” peaks -Blue tames these peaks down and stays far away from sibilance.

I found this also to be the case in the heavy metal genre - a genre that is known for being on the edge and being bright. “Crazy Train” by Ozzie Osbourne, “When a Blind Man Cries” and “Enter Sandman” by Metallica, and multiple songs by AC/DC, Iron Maiden, Black Sabbath, and Judas Priest, are all examples where this can be heard well. At no point did I encounter the Blue to hint any sign of sparkle, which essentially proves that Dekoni Audio’s description of what they did with the Blue is indeed correct: “The Dekoni Blue is warmer, smoother, and less fatiguing than its predecessor, making for hours of comfortable listening sessions”

I found myself enjoying some female artists such as Nina Simone, Freya Ridings, Demi Lovato, Sia, and even Gloria Gaynor. In particular, “Poison” from Freya Ridings and “Anyone” by Demi Lovato were two songs where I particularly enjoyed the upper mid-range.

“Bohemian Rhapsody” by Queen is a classic. While the overall presentation sounded good with the guitars, drums, and the piano, Freddie’s voice did sound a tad too warm and a bit recessed at the 2:17 minute mark - where Freddie sings “…face the truth”.

“Soldier of Fortune” by Deep Purple is another favorite of mine. Specifically the guitar introduction -the upper end sounds very nice and pleasant. The guitar plucks at the very beginning have pretty good timbre and tonality, just like a real guitar should sound like - yes, maybe the sparkle isn’t there, but they can very much be felt, which is definitely something I look for.

“Babe I’m Gonna Leave You” by Led Zeppelin is a highly dynamic and slightly intense track. The guitars here also sound superb - even when the track gets very busy and crowded, the Blue manages to keep up with the guitars. The same goes for Robert Plant’s vocals, but his voice is a little distant in the original recording.

All and all, the Dekoni Blue sounds the best in tracks that aren’t too busy, it is more than capable of keeping up with a very good guitar solo. The warm signature results to a fatigue-free listening experience, but this does take away from the details in the upper mid-range. I mainly found my comfort zone with the Dekoni Blue in modern music, especially mainstream pop and r&b.


The Blue keeps the high-range nice and clear. It keeps a good balance of detail and staying away from sibilance and brightness. As long as you are not listening to older and less mastered tracks, you won’t face any type of piercing or fatigue.

“Stop Trying to Be God” by Travis Scott is my standard testing track for sibilance. While I am not listening to Travis’s vocals, I am listening to Stevie Wonder’s harmonica at the outro of this track. What I always look out for is the clarity and tonality of the peak at 5:59 minute mark. I was very happy to hear that the Blue can deliver a very clean sounding performance and be exactly on the edge of sparkle. The harmonica’s peak note is pretty bearable and gives that satisfying ear feeling that you get from a good treble response.

Even with very harsh and not the most ideally recorded tracks like “Babe I’m Gonna Leave You” by Joan Baez, Blue doesn’t result to fatigue. It’s a particularly easy recording where the peaks are happening quite often, but the Blue tames it down to a level that is listenable and bearable.

Whether it’s modern pop, r&b, or even hip-hop/rap, the percussion always stays crips. In “Montreal” by The Weekend you can hear that the snare sound very clean and has the top-end that it is meant to have - it sounds tight and compliments the rest of the mix. “Still Dre”, “The Next Episode”, and even “Forgot About Dre” all share the same quality. The Blue presents the high-end from the percussion with a clean sound, the snare hits always sound in place and are more forward in the mix.



Dekoni Audio said everything that needed to be said about this headphone: “The Dekoni Blue is a Fun Headphone with a great bass extension and smoothed out high end”. As you can notice, Dekoni was honest with the marketing and didn’t claim any bold or absurd claims.

The true qualities of the Blue lie in its comfort, bass response that fills the mix with its presence, and the fairly pleasant high-range with a roll-off that is caused by the warm sound signature. The Blue is best suited for tracks that aren’t too busy. If the track is too busy, especially if it has a lot of low end, the mix can be overwhelmed with the bass presence, hence why I personally enjoyed less busy tracks. Clean 808s sound very good with the Blue, which is the reason why I preferred to listen to some modern mainstream tracks.

The low end of the Dekoni Blue is heavily focused on quantity - it will fill the mix with the presence of lower frequencies. If I was to describe Blue’s bass response it would be compared to that of a mallet drumstick - gentle and soft without much definition. I always perceive it as soft bass and visualize it as something very fluffy and soft. On the other hand, the opposite of that would be a tighter bass response; and it could be compared to that of a wooden drumstick, which is tight, fast, and sharp. Both of these are quite different, the first one is more relaxing, while the latter is more noticeable & audible.

My main preference in terms of music were clean tracks that didn’t have too much going on. Here are some particular tracks and albums that I greatly enjoyed listening to:

Partynextdoor - Spiteful
Sia - Greatest
The Weeknd - Montreal
Jaden - Syre (album)
Daft Punk - Tron: Legacy (album)
The Weeknd - After Hours (album)
Peter Green - The End of the Game (Expanded) (album)
Kendrick Lamar - good kid, m.A.A.d city (Deluxe)
Joni Mitchell - Blue (album)
Céline Dion - Falling Into You (album)

I can safely say that the Dekoni Blue will be a headphone that I will use for entertainment purposes (movies, games). The Dekoni Blue is a very comfortable headphone with a fun v-shaped sound signature - while I personally am not drawn towards warmth (I prefer the buzz and feel from the high frequencies), it can certainly satisfy somebody who likes a warm sound signature and someone who likes bass presence. I can also see the Dekoni Blue as a headphone that you throw on while you are doing something and not entirely focusing on what you are listening to. Dekoni Blue doesn’t distract with it’s sound signature, and this is the main characteristic of the combination of a warm sound signature and less defined bass region.

Below you can go through several links that I used for the history section. A lot of them are quite interesting, but there are a lot of sources…
Regardless, here they are:


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1000+ Head-Fier
Pros: bass, comfort
Cons: look goofy, cable
So, after hearing these and buying them at RMAF this year, I sold my DT 1770's, which I loved and had modded to improve the sound. Why did I do that? One main reason: the bass. I enjoy the 1770's and they were my first real audiophile headphone. They are built like tanks, and sound great, but the Dekoni's have the most articulate bass I have ever heard. Do they look as good? No, they are kinda goofy design, but they are lighter, and the pads are super comfortable. Cranking the bass up, it is just so well defined without being muddy or boomy, not that the 1770 is boomy. This just does what the 1770 does sonically a little bit better--not a ton better, but enough that I reach for these over my 1770, so 1770 didn't stick around. I still love Beyer, but these are just legit headphones. I would like a better cable for them, but at $199, I'll buy an aftermarket cable.

Buy them!
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Headphoneus Supremus
Pros: Affordable.
When driven, can provide a good sound.
Decent enough sound, when properly driven.
Cons: Plastic.
another modded T50RP
Bass can be bloaty.
Needs proper driving force behind it.
The Dekoni Blue. It won’t keep you in a blue mood…


From the first rip in Jumpsuit, you are hooked. The depth of bass on Turbo mode through the iFi iDSD micro Black Label will draw you in and throw you down. You feel the thrust of that bass rumble (not shattering like some but controlled) and know the Dekoni Blue means business. This headphone was meant to rock. Straight up business.


The Dekoni Blue and the official mod are the offshoot of the infamous Fostex T50RP, the venerable go-to mod headphone for those on a budget. The T50RP is legendary for its ability to be modified and hold its own against much more expensive headphones. To me, this would be the equivalent of the 70’s muscle car, which is modded to take on the world. I owned a pair of Fostex T40RP Mk2 for a bit of time. I liked its bass presence and performance. I will explain more as to why it has left my stable.


I thank Dekoni for running the Blue tour, and for the inclusion of the Fostex HPA4 BL headphone amp. The two are meant for each other.

Gear used/compared:

Focal Elea
Grado GH-2 Limited
Thinksound ON-2

Thebit Opus #2 w/ iFi Micro iDSD Black Label
Macbook Pro/Fostex HPA4 BL/ iFi Micro iDSD Black Label
Questyle QP2R solo


Frequency Range: 15-35,000 Hz
Nominal Impedance: 50 ohm
Sound Pressure Level (SPL): 92 dB

Songs used:

Too bloody many to list all, but you want songs, so there you go:

Coldplay-All I Can think About Is You
Coldplay-A Message
Coldplay-White Shadows
Dona Onete-Sonos de Adolescente
Los Lonely Boys- Heaven (en Espanol)
twenty one pilots-Trees
twenty one pilots-Car Radio
twenty one pilots-Heathens
Damian Marley-Everybody Wants To Be Somebody
Damian Marley-So A Child May Follow
Damian Marley-The Struggle Discontinues
Ziggy Marley-Lighthouse
Ziggy Marely-See Dem Fake Leaders
Mark Knopfler-Laughs And Jokes And Drinks And Smokes
Santana w/ Mana- Corazon Espinado

The new twenty one pilots album, Trench


The Dekoni Blue has the typical Fostex build quality. That means it is plastic but can take abuse as many Fostex headphones make their way into the DJ realm. With a sturdy, but not much padding band, it can bend a good bit so one need not worry about that aspect. Pads are held on by small pleather lips, which slide into narrow slits on the headphone itself. From my past experience with the T40RP mk2, I found that to be a pain. So after one listen with the all-velour, I switched back to the hybrid pad and left them there.

With a detachable cable that is fairly sturdy, you need not worry about it being Focal Elear constrictor-weight. With a good weight and feel, it is about right. A nice locking mechanism keeps it on, and you cannot mess that up.

The blue plastic housings are BLUE. Sky blue almost and not bad to look at. They are different than the Fostex phones, as they should be. Nothing too obtuse, or divisive. Overall a decent looking headphone, that will draw a bit of attention to itself, maybe even a query from those in the know, much the way another modifier of the Fostex brand would. Not a bad thing, really.

With no microphonics whatsoever on the cable, you need not worry about being interrupted by that annoying rub. The only qualm I have regarding the overall finish are the exposed cables coming out of the pads that go into the band. They stick out a bit too much for my comfort.

As for fit, the Blues are comfortable overall, but I did find after about an hour with glasses and an ear ring they became uncomfortable. To the point where I either had to change headphones or take a break. This was one of the main reasons I sold my T40’s, because they became uncomfortable, even with the lighter pressure than some of my other headphones. Take that as you may, since many have espoused the virtues of the Dekoni fit. I would love to try some of the Dekoni pads on my Elear for a cross comparison.

ON-2: better bass control. Deeper reach and more of it. Clearer sound-better detail retrieval. A brighter sound signature as well. Better isolation. Less fatiguing. Fit while good tend to slip. Grip pressure is about right. I had less of a problem with the ON-2, than the Blue.

Grado GH-2 limited ed: more mid forward. Less bass (open back…so). Details on par with ON-2, but less bright. A more “mature” sound, but not as warm as you would think. Vocals are sumptuous. Fit is near ideal as the GH-2 is about as light as a feather. Once music starts, forget about it, except for isolation, which is all but non-existent. I can clearly hear me pecking on the keys. Bass is solid, but no rumble. Simply put, it is there and clear. Heavy cable, which detracts from an otherwise stellar product. Plus, the cable is not detachable. Not a deal breaker to me.

Further detail:

Sometimes I peruse all that is written about a product before it arrives. Other times, I don’t. This would be a case of the latter, since I had experience with the T40, and had previously read extensively about the T50 mods. I will admit it was quite fascinating what some had achieved, and I liken the T50 mods to modifying a 70’s American muscle car, whether it be Mustang, Camaro, or Challenger. All have their benefits and some darn fine (and fast!!!) cars have been the result.


So, in that light I did anticipate what Dekoni had done as I heard very good things about the pads they produce as after-market for a variety of headphones. If they could do that to a headphone, then it would be a winner and compete comfortably with the other modded Fostex iterations. So, not having experience other than an ill-fated T20rp mk2 purchase I made as well as the new T40RP mk2 I purchased new, this would be a strict comparison to what I had on hand already.

Upon receiving, I checked to ensure all was there, and I understood how the critter worked with the included Fostex HPA4BL amp. I also had to dig deep for some interconnects, but that is OK in my book. Once hooked to the QP2R/xCAN combo I lit her up so to speak. Sort of. Not able to draw enough volume, I dragged the Fostex amp out and hooked it into my MBP. That was better. Providing decent power and a good sound, the combo wrought decent enough bass, and clarity, but seemed lacking. I could certainly get the volume high enough, but the sound did not impress me the way I thought.

Switching to my iFi micro iDSD Black Label afforded me more options with which to hook. Immediately (OK, after tuning to the “Turbo” mode) the sound was more vibrant, richer and fuller. Packing up the Fostex, it would remain in the box for the rest of the test. THEN, I hooked back into my QP2R for a quick listen and all was good. I checked the Shanling M3s as well, and my trusty M5 as well as the Opus #2. All was good. That said, the majority of my time was spent on the BL/MBP combo using either Tidal from my playlist or random bits of work, or Pine Player and the new twenty one pilots album, Trench. This album should immediately be brought into everyone’s queue for testing purposes. A more mature brand of TOP, there is still enough reverence for their history to know and understand this is the next logical iteration of their sound. Fabulous it is, and wrought with such variation of sound, that it alone would be worthy of use for a full-on review of any gear at hand. Good stuff.

Once the sorting was done, I noticed how the Dekoni needed a good bit of power to successfully play. This is the first set of cans, which has needed the Turbo setting on my Black Label. While I could use normal, the volume needed was such that distortion came into play if I tried to really drive the Blue. Once on Turbo though, no problem. So, find an amp with enough juice to drive them properly lest you do yourself and the Blue a disservice.

With the BL at slightly less than half volume on Turbo, the sound is deep, rich and near-vibrant. Changing between XBass+ being on or off as well as the 3D+, you could fine tune much the way one would to personalize your critter in hand. With both on, Smithereens sounded light delicate and pronounced. With Tyler’s thumping bass to fill in the sound, you could gain an appreciation for not only the new TOP sound, but for how well the Blue can scale and “adapt” outside of sheer driving rock/metal/edm mode.

Follow that with the melodious Neon Gravestones, and you begin to understand the tuning Tal & company brought forth in the Blue. The T50RP is good, very good for its price. The Blue is excellent. I thoroughly approve of all tuning aspects and find this a good bargain at the $299 price range. On sale for Black Friday at $199, ramps that up to an excellent value. Smoothing out the typical T50RP “harshness” the Blue provides a very good mellow sound, with an authoritative rumble of bass. Especially when you have a bass switch on an amp.

I did find the bass a bit overpowering and boomy, with a lack of control on some songs. When I switched the XBass+ off though, the sound came back under better control. Other times I left the switch on, even with that boomy sound just for giggles. Kind of fun, it was.


Dekoni Blue ($299) vs thinksound ON2 ($130):

The ON2 was a gem I took a flyer on, purchasing a used set. Having not heard it before, I was a bit apprehensive at the purchase. Upon arrival and a listen, that thought quickly left the state of Missouri and is currently floating above the Pacific I believe. As an on-ear, the fit is very different. Made from sustainably-harvested wood, and recycled plastic, I loved the environmental aspect of the ON2. It made sense to me, and I still do not understand why it has not gotten more attention. It is quite good.

Immediately different between the two was how the mids are presented. Mellow tuning would be the verbiage used for the Blue (another departure from the T50RP). Forward would be one way to put the ON2. Bass quantity is definitely present, and a bit better controlled than the Blue. Rumble is present, but not in the quantity of the Blue. I also think due to the mellow nature of the Blue, that detail representation is a bit better in the ON2. This really isn’t a slight against the Blue, just the way it is. That mellow-er sound draws you in, enveloping you and it is good. The almost-bright characteristic of the ON2 is fabulous, and due to its more portable nature as well as isolation would make a wonderful pair to use on the train. I really like the ON2, and for the price an absolute bargain. Two approaches, two different results, neither bad.

Dekoni Blue ($299) vs Focal Listen ($249, blowout for $129):

I will openly admit that my pair of Listen get shoved to the back of the queue too often. Purchased as a comparative tool, I do not bring them out often enough. So as luck would have it, they fit right into this review. If you have been around the planet for the last several years and within the audio world, you know of Focal. First a loudspeaker maker, then branching off into headphones, their Utopia is widely (not without criticism) thought to be one of a handful of the greatest headphones ever produced. Outrageously priced, the sound is of legend. Many purchased a pair simply because…Me? I opted for the more “affordable” option and the Elear. That purchase spurred the purchase of the Listen. In and of itself, the Listen is rather uninspiring. Not really a bass model, nor neutral; it was thought to be Focal’s attempt at drawing the Beat crowd, what with its more affordable price. Relegated now to the wireless version (mine are not), it quickly became the forgotten model. But at that blowout price…another story.

As an overear, the Listen isn’t that comfortable, or versatile. It can fold quite small for portable/commuting use, which is a benefit. Without the XBass+ or 3D+ on, the Listen becomes quite average. With both on, there is good bass, and a clear treble sound. With mids well behind the ON2, it takes a second in that realm. The Blue bests the Listen in the bass department, and other than the transparency of the Listen, pretty much beats it in all categories. Don’t get me wrong, the Listen is still worth a look at the price now, but there are better options.

Dekoni Blue ($299) vs Grado GH-2 Limited Edition ($650):

As part of a TTVJ demo tour, I was lucky enough to audition the GH-2. I liked it so much and appreciated the history behind the brand that I purchased one of Todd’s last pair. I do not regret it at all. Unfortunately, due to my “family” circumstances, using an open-back headphone is not very copacetic with the wife-unit (whom I love very, VERY much). So, other than the odd day alone or review comparison the Grado does not get much love.

The open back belies the bass, which is present. Rich, full and on par with many semi-open and closed-back headphones make the GH-2 a stellar representative of the Grado brand. My review sung of the virtues of the tune. Details galore, as well as a transparency, which allowed the history of Grado to shine through, there is a reason some follow the brand fanatically. A method that works should not be messed with. I will state that there is a bit of an odd sound regarding the mids which some may not find appealing. I like it simply because it ties the treble to it with aplomb. A bit of sparkle leads to a sound, which contradicts the open nature of the headphone. With decent enough bass, and a fit, which makes the GH-2 feel as if they are all but non-existent on your head make for a winning combo in my mind. Even with that silly Anaconda of a cable. This is a good unit but looked at for completely different reasons. I posit the comparison still holds, as some within the Fostex modded department aspire to bring the price into that range. Thankfully, Dekoni did not.

Dekoni Blue ($299) vs Focal Elear ($699ish):

Fashioned as the result of another TTVJ tour, the Elear was my second purchase into the realm of upper-end headphones, after the Grado listed above. I love my Elear and everything about it (except that silly Anaconda cable, which was consequently replaced). I quickly replaced all cables with three sets of LQi cables of the 3.5mm SE, 2.5mm bal and balanced 4-pin XLR variety. It still holds its place in my signature as favorite along with that incredible Apex Pinnacle 2 and the QP2R. Wow, just wow. That said, I believe the comparison is again valid as Dekoni strives to achieve above the level of the T50RP, and based upon all of the comparisons above, it has. Better bass quantity than the Elear it moves ahead. It cannot compete with the detail or clarity of presentation though. It really isn’t meant to, since the price is at least 2x between the two. Where there is better detail retrieval with the Elear, there is better bass in the Blue. Where there is better clarity in the Elear, there is that mesmerizing planar sound. So, you see, the Blue is quite worthy.

What leave us, thee?

So, after all of that non-sensical comparison gibberish above, what are we left with? We are left with a pretty doggone decent headphone. One in which a company took an established model and is trying their hand at raising that to the level of other modifiers. With full blessings I might add. And in that regard, the Blue is worthy of consideration should you be looking. I am one of the few who mentioned the fit issues, so it must just be my silly big head. Take that as you will, but know that if you wear glasses, it may be a compromise you make. And it would be OK in the long run, since the Blue is a pretty darn good iteration of the Fostex T50 RP mk3.

The Dekoni Blue is a wonderful sounding headphone when properly driven. It ticks all the boxes for someone who wants good bass, decent transparency, and a decently-wide soundstage. Under the tutelage of my Black Label, I could make it sing properly and that is a good thing. Well done, Tal & crew.

I thank Tal & Dekoni for sending their product out on such a lengthy tour, we greatly appreciate the opportunity to peruse the product. And as mentioned I have ended up with a couple of very fine products as a result of tours. Not a bad way to spread the wealth.



Headphoneus Supremus
Pros: The blue color, nice hefty feel, comfortable earpads
Cons: Overall sound and resolution
1 - tvdZgwV.jpg


Disclaimer: I am not endorsed by Dekoni Audio for this review. I did not pay for this product being the nature of a product tour. All I wrote are my honest thoughts on the product.

First off, a big thank you to Dekoni Audio for the opportunity of being a part of the tour. In this tour, I get to demo a pair of the Dekoni Audio Blue for a week along with a Fostex HP-A4BL DAC/amp. This is my first time being a part of a tour for any headphone, so I’m very excited and thankful!

I haven’t actually heard many T50RP mods even with the abundant companies that mod them and guides to mod them. I did work on a mod on a T50RP MKIII but had no idea what I was doing and sold them long before I really got into modding. Other than that, the other T50RP mods I’ve listened to are the MrSpeakers Alpha Dog and ZMF Ori.



So I guess as an "about my preferences", I like a warmer sound signature though I don’t like too much mid-bass emphasis. I do like some emphasis in the sub-bass however. I generally like the 2-5 kHz range to be a bit laid-back - helps vocals and overall timbre to sound more warm and natural (or at least to me). I find emphasis in this area to make vocals sound shouty and unnatural. I really dislike being drilled by any sorts of sharp peaks in the treble. So basically, a bit warm and smooth.


  • Driver: Planar magnetic, same driver used on the T50RP MK3
  • Impedance: 50 ohms
  • Weight: 320 grams
  • Sensitivity: 92 db/mW (more on that below)
  • Frequency Response: 15Hz - 35kHz
  • Maximum Input: 3000 mW
  • Cable: 2m or about 6.5ft, terminated into a 6.3mm/1/4” jack, comes with an adapter for 3.5mm compatible devices
Alright so the sensitivity listed here is 92db/mW at 1kHz with 1mW, that means these have the same identical sensitivity listed on the T50RP MK3. However, the sensitivity should be much lower because of the added distance from the earpads. I would think the sensitivity would be from 87-90db/mW. I would recommend a beefy amp to power these things.

6 - JVnYeRS.jpg



It feels like a T50RP. Actually, there seems to be a bit of heft here in comparison to a stock T50RP. Probably just from the earpads. It has a nice weight to them, and may or may not survive a few drops.

3 - AkkqeE2.jpg



These are semi-open as with the original T50RP MK3 in that only the bottom vents are opened. I believe the T20RP MK3 has both top and bottom vents opened and the T40RP MK3 has no vents. The Blue muffle sounds a bit but you’ll still hear your surroundings. These do leak quite a bit because of the semi-open design.


Fit & Finish:

These are, of course, infinitely more comfortable than a stock T50RP with its thick earpads. The surface that actually touches the side of your head is a type of velour (with the provided angled hybrid and “flat” earpads). The headband seems to have a bit of cushion which I don’t remember being on the stock T50RP - it has been a while since I last owned a T50RP, so I don’t remember if it’s the same headband. It does develop a bit of a hotspot on the top of my head. They don’t feel too heavy on my head and the earpads are very comfortable. Clamping force is light but adequate for a good seal which is probably helped immensely by the thick earpads.

The headband yoke is now coated black which I find to be a handsome and welcomed change. The earcups are now blue as the name of the model would imply - it’s like a “70s diner” kind of blue; I like it.

4 - HyGAj2X.jpg

3 - AkkqeE2.jpg



For the majority of this review, I used the provided Fostex HP-A4BL for no EQ and my Gustard H10 for EQ (as it can push more power when I lower the pre-amp). I primarily used the “flat” velour Dekoni pads provided with no EQ.

Unfortunately, I’m going to sound very critical from here on out.

First Impressions (same with both pads):
  • Midrange is very recessed and overall sound is uneven
  • Bass doesn’t extend well into the sub-bass, rumbles are non-existent
  • Bass is very boomy but doesn’t have much “weight” to them
  • Treble is fairly bright and gets fatiguing after a short while
  • Not very detailed nor clear throughout. Muffled sounding
  • Overall, unnatural sounding.
Now, my thoughts are more or less the same.

7 - mDfMbiA.jpg


The bass here is very odd. These do not extend low very well. I do not hear/feel any rumbling or feel the “weight” or impact of each note - as some sort of reference, I find adequate “weight” or “body” with a linear or slightly raised response going from 100-20 Hz. On the contrary, these have a BIG mid-bass emphasis that creeps up into the midrange. What’s odd to me is that it sounds very bloated andthin at the same time. It’s weird, I know. The overall response of the bass is uneven which I find makes acoustic drums sound unnatural. It kinda works for EDM with the mid-bass bump but again, don’t expect any rumbling or a good ‘hearty’ bass.

Overall, I don’t like the bass response. It sounds bloated and is not well-rounded. I am led to believe that these were not damped incredibly well or at all.


The midrange sounds very recessed. This is partly due to the big mid-bass hump and also, I believe, from added distance given by the thick earpads. Guitars and vocals sound very distant and congested. The response here is not very detailed nor resolving - most likely masked by the heightened bass and treble response.

Overall, I don’t like the midrange response relative to the bass and treble response. Vocals are muffled and details that fall within this range are either masked or blurred.


The response here is elevated and fairly harsh. The headphones are fairly bright, and it does get fatiguing over a short period of time. It is very unforgiving, so poorly recorded/mastered tracks will sound unpleasant here. The sense of immediate detail here seems good with its heightened treble response. However, it’s not a very pleasing response as it sounds way too bright and fatiguing.

Overall, I can’t say I like the treble response here. It does not compliment the midrange well, is sibilant and harsh, and isn’t very pleasing.


These don’t sound particularly wide. Instrument separation is ok for the most part - I say for the most part because the mid-bass bloat seems to congest and blur the localization of instruments a bit. On that note, imaging is just ok.

I illustrated what the soundstage would “look like” below:

Dekoni Audio Blue soundstage comparison - Imgur.jpg

Pad differences:

Simply put, the angled hybrid pads give a brighter tone. Vocals are a bit more forward on the angled hybrid pads. Otherwise, there were no sonic differences that I noticed.

I actually have stock T50RP MK3 pads on hand, and uhh.. I like the sound with these more.. It’s a lot more balanced. Measurements in the link below.

8 - zyBS1Xc.jpg




These don’t take EQ particularly well. I’m getting audible distortion bumping up the lower registers (<30 Hz) even while lowering the pre-amp - I think this may be the driver reaching its limits. The midrange and treble are just screwy.

It still doesn’t sound very good but here’s my EQ as of writing this:

Pre-amp: -8db
  • 30 Hz: +4 db, Q: 1, peak filter
  • 50 Hz: +4 db, low-shelf filter
  • 70 Hz: +2 db, low-shelf filter
  • 115 Hz: -5 db, Q: 1.5, peak filter
  • 300 Hz: -8 db, low-shelf filter
  • 375 Hz: -4 db, Q: 1.5, peak filter
  • 700 Hz: +4 db, low-shelf filter
  • 2000 Hz: +2 db, Q: 1, peak filter
  • 2750 Hz: -4 db, Q: 2.5, peak filter
  • 3000 Hz: -6 db, high shelf filter
  • 4000 Hz: -4 db, high shelf filter
  • 4400 Hz: -3 db, Q: 4.32, peak filter
Alright some of the settings seem counter-intuitive or redundant but that’s just what I got. Measurements in the link above, at the bottom of the album.

I keep the pre-amp fairly low since I have a couple songs that still manage to peak the clipping meter.



To sum up, I did not like the Dekoni Audio Blue. The odd bass response, recessed midrange, and the harsh treble all add up to an unpleasant listening experience. It is not very resolving nor detailed overall - everything just sounds blurred and congested. At the price of 199 USD new, I am disappointed to say that I cannot recommend these. There are competitors that are better below or at that price point. It seems these headphones are marketed to those who wanna dip their toes in planar magnetic headphones, but I’d recommend an HE-400i or HE-4XX for that. Hell, those cost less than the Blue right now! I daresay that I like a stock T50RP MK3 more than the Dekoni Audio Blue, comfort aside.

As for a suggestion, I would like the mid-bass to be dampened and have better extension, the midrange ironed out (for a less jagged response), and the treble to be smoothed out. I think the frequency response will be better with thinner earpads. These definitely need a re-tuning. The modder in me really wants to take a crack at it but this is just a demo unit so I can’t :wink:

Please let me know if I made any grammatical errors!

2 - c9dWT0h.jpg
A fair assessment and well laid out review, thank you!
We appreciate your review, & your participation in the tour. Even if we didn’t get to thrill you & earn an instant recommendation, it does give the community a data point to consider and hopefully someone seeking a flat neutral response won’t try these and be disappointed, while someone desiring a warm and full bodied sound may still enjoy what they find in this.
Great honest review, straight to the point with science to back up your impressions.
Wish more reviews were like this (RIP innerfidelity)


Headphoneus Supremus
Pros: improved bass quantity and extension and less grainy treble than stock t50rp
Cons: shares durability concerns of standard t50rp

Dekoni Blue

I received the Blue and a Fostex DAC/Amp as part of the Head-fi tour. I have received no compensation of any kind for my review.

I will start this by saying that after receiving the Blue, I sat and thought about how many Fostex RP variants I own or have owned in the past. I count no less than 6 and I am limiting this number to those that share the original T50 shell. I’ve owned a few more with t-series drivers that had been reshelled by such makers as Mr. Speakers and ZMF but won’t compare to those as I think it unfair to do so.


The Dekoni comes packaged nearly exactly the same way the Fostex counterpart does. Simple cardboard box, with headphones and two cables in bubblewrap. Not the most elegant arrangement and if I were shipping long distances a bit of extra padding would be appreciated here. It is a pretty no-frills packaging but at the price point of the Blue, not wholly unexpected.



Those familiar with the RP series will find the Blue to very similar. The Blue does have a serial number displayed on the inside right of the headband that isn’t present on the t50 and I like the subdued black of the sliders and cable between ears when compared to the original. The only other visible difference between the Blue and the t50 is the pads. I have long since replaced the pads on my t50 models with ZMFs or others as the stock pads are somewhat atrocious. Dekoni has done a great job creating a pad for the t50 that is both comfortable, doesn’t overheat, and works well with the sonics of the shell. I traded them for a ZMF pad on my Classics just to see what contribution the pads play in the sound and found the Dekoni to be every bit as good or better than the ZMF pads on both headsets. If you already have an RP series headphone and are not in the market for the Blue do yourself a favor and at least order the pads, you wont be disappointed.



The tour unit shipped with the 6.3mm twist lock cable but again unlike the Fostex counterpart, it is shortened from 9 to 6 feet and the connectors are gold plated instead of chrome(Fostex). Product documents show the Blue in retail form also ships with a 3.5mm cable so I have to assume this went awol on the tour sometime before the blue arrived. I used the standard orange version of the 3.5mm cable from my stock to test with portable sources in the absence of the Dekoni version.


Dekoni doesn’t list any changes made to the drivers so I started with the assumption that the Blue would be relatively hard to drive. The fact that a fairly high powered amp was provided for the tour also hinted that Dekoni wanted to make sure the testers had an amp of adequate power to enjoy the blue. For my testing, I used my Burson Fun amp paired with a recent acquisition, the Audio-GD R2R-2 (Birthday gift from SWMBO). This pairing has more than enough power to wring out everything the Blue is capable of and enough detail to really be able to test the limits of the Blue’s resolution. I will say that having not had a chance to audition the little Fostex dac/amp that came with the Blue I was impressed with its output power and ability as well and it was a good match for the Blue within the limits of both. I’ll write up the dac/amp in a separate space.

For testing with portable gear, I used the Opus #1s and the Xduoo XD-05 with Burson’s V5i op-amp installed. This was the most potent combo I had and if you are going to use the Blue as a portable headphone I would encourage you to investigate either the Xduoo or the iFi BL if budget allows. The Blue is a power sponge and will take everything you can give it.



Dekoni has outdone themselves and I will readily admit to fighting the urge to take a screwdriver to one of the housings to see what black magic they have done inside. I have always thought one of the faults of the Fostex rp series driver is that it rolls off fairly high up and bass extension cannot be made all that great. I’ve had several pairs that had good bass quantity due to various mods, but never has the bass reached as deep as the 900 series fostex or many other planars (Oppo). Dekoni has found a way to coax every last bit of extension out of the driver and boosted the quantity while still maintaining reasonable clarity. Mid-bass is pushed forward but no perceptible bleed into the mids was present leaving a nice warm signature with adequate bass detail and good impact. Those lamenting the lack of bass in the t50rp will appreciate the angled pads of the Dekoni as they bring a bit more thump.


Mids on the Blue are mildly recessed when compared to the mid-bass but still enough ahead of the treble to produce an overall warm and slightly dark sounding headphone. Details on the mids are good and parallel what we have come to expect from the RP series. I think Dekoni did very little to tune the mids of the original t50 and that is ok with me as it is one thing the t50 did reasonably well out of the box.


Dekoni has done something to the treble on the Blue that makes it slightly less fatiguing and notable less grainy than the original T50. This is a subtle change as at first I would have told you that like the mids, they had not altered the sound, but as I listened more, I realized I wasn’t hearing the grainy treble I did at times with the t50 and my ears were not getting nearly as fatigued as they had with the t50 listening session preceeding the blue.


The Blue is very much a t50 when it comes to soundstage as the stage is deeper than wide with acceptable but not spectacular height. I do think the angled pads help deepen the stage a bit but do nothing to widen it and may actually narrow it a bit when compared to flat pads.


The Blue images well and with its quick attack and decay some gamers may find the Blue to be a good all-around headphone that can be used both at the gaming system and when listening to their favorite LPs.


Dekoni has smoothed off a lot of the rough edges of the t50 and while some will dismiss it as something they could do at home for half the expense and a couple hours effort, I don’t believe that is the case. I have modded several t50s over the years and can honestly say that none of my home shop versions are as good as the Blue. Some modders may be more skilled than I am but I suspect without a 3d printer to rework the geometry of the baffles, you’d be hard pressed to replicate the Blue.

Dismissing the fact that the Blue is a t50 variant and looking at it as a standalone for a moment. Blue does a lot right. Bass is good both in quantity and depth, transitions are smooth and flowing, treble is non-fatiguing and overall the warm signature lends itself to prolonged listening sessions. In talking with a friend I said the Blue was nearly as addictive as the Campfire Cascades if not as resolving or quite as extended. I can also draw a comparison between the Blue and the TR-x00 models which puts the Blue in good company. I think regardless of their pedigree, the Blue stands on its own as a very solid $250 headphone and is well worth a look.



1000+ Head-Fier
Pros: Detachable cable, easily changeable pads, durable, fun sounding
Cons: bass bloat, recessed mids, cable running between the two headphones are exposed,

Arguably one of the most popular headphones to mod ever brought into existence is that of the Fostex T50RP (in insert whatever variant is currently out). I can hear all what ‘say whaaaaaaaa’s out there when I say that I’ve never heard one or any of their mods before. So when Dekoni was starting a tour for their new Blue headphone, I had to put in my name to see if I could end that spell. In addition, I’ve been wanting to see what these Dekoni pads were all about as well. So I’ve now had a week to spend listening to them and both the Elite Hybrid and Elite Velour pads that came with it and am quite excited to share my thoughts on the Dekoni Audio mod of the Fostex T50RP mk3, the Dekoni Blue.

A little about me

I would like to say that first and foremost I am NOT an “audiophile” but rather an audio enthusiast. I listen to music to enjoy it. Do I prefer a lossless source? Yes, of course. But I can still be very happy streaming from Pandora or even my YouTube “My Mix” playlist. I also prefer equipment that sounds the best to me personally regardless of what frequency response it has or rather or not it's “sonically accurate” and I always have and shall continue to encourage others to do the same.

I'm a firefighter for both the civilian and military sector and the cliché of wanting to do this since I was born couldn't be more present with me. I've worked hard over the last several years to earn this position and now it's time for me to work even harder to keep it.

My interests/hobbies are powerlifting, fishing and relaxing to audio products and reviewing them to help other decide on what products would work for them. Few things make me as an audio enthusiast/review feel more accomplished than when someone tells me that I helped them find the type of sound they've always been looking for.

Now, the sound signature I personally favor is a relaxing, warm and sensual sound that just drifts me away in the emotional experience of the music being performed. Yes, accuracy is still important but I will happily sacrifice some of that if I'm presented with a clean, warm sound that can wisp me away into an experience that makes me yearn for more.

My ideal signature are that of respectably forward mids and upper bass range with the bass being controlled but with some slight decay. I like my treble to have nice extension and detail reveal with a smooth roll off up top as to not become harsh in the least. Examples of products that have given me chills and keep giving me the yearning for more feels are the (in no particular order) Bowers & Wilkins P7, Oppo PM-1/2, Empire Ears Hermes VI & Zeus XIV, Audeze LCD-XC, Meze Headphones 99 Classics.

Equipment used at least some point during the review


-Schiit Ragnarok

-Fostex HPA4BL


-Schiit Yggdrasil


-LG V20/HP Pavilion

-Playing Pandora, YouTube, and various format personal music


I am by no means sponsored by this company or any of its affiliates. They were kind enough to send me a product for an arranged amount of time in exchange for my honest opinion. I am making no monetary compensation for this review.

The following is my take on the product being reviewed. It is to be taken “with a grain of salt” per say and as I always tell people, it is YOUR opinion that matters. So regardless of my take or view on said product, I highly recommend you listen to it yourself and gauge your own opinion.

The Opening Experience


Why I feel so strongly about the initial unboxing experience

Please allow me to explain why I feel so strongly about the initial unboxing experience with a product. Maybe it’s due to my southern roots in the hills of eastern Kentucky, but I’ve always been raised under the pretense of when you introduce yourself to someone for the first time you present yourself with confidence, class, character, pride, and competence. You greet the other person with a true warm smile, eye contact and a firm handshake. Anything less or short implies to other person that you either don’t care about them, are too full of yourself, too busy to be bothered by the likes of them, or worse, just generally disrespectful.

As a consumer, I take this same belief to when I open a new product. Why? Because think about it this way. How else can a company introduce themselves to their customers? How do they present their products? Are they packaged with pride and presented in such a way that makes the listener eager to listen to them? Or maybe they’re just wrapped up and placed in an available space. How about the box itself? Is it bogged down with jargon that says look at this, look what I can do. I’m better than anything on the market and here’s why read this and check out that. Or, is the package clean, simplistic and classy? As if saying to the customer ‘Good day, pleasure to meet your acquaintance. Please give me a listen and allow me to show you what I can do and allow my actions to speak louder than my words.’

This is why I feel so strongly about the initial presentation of a product, and I feel it’s truly a shame more people don’t. But with all that aside, let’s discuss how this products introduced itself shall we?

Well. I really don’t have a lot to say about my handshake. It was a very, ‘here you go’ experience. The Dekoni comes in a really nice simplistic blue box with really only some specs on the back and their name on the front, which as you likely know if you keep up with my reviews, I really, personally, enjoy. As you open the box you’re greeted with the startup guide and warranty, then right under that you’re given a pair of extra pads (either Elite Velour or Hybrid [not positive if this comes with all Dekoni Blue’s or just for the tour but the website makes me believe they do]) and the headphone wrapped up in basic bubble wrap. Yup, bubble wrap. And that’s it. I feel like I wasn’t even given a handshake but rather a rep. idly giving out his/her business card to whoever they come across. So to say I was a bit underwhelmed/disappointed would be an understatement.



Construction is pretty standard by today’s methods. The frame is made of aluminum, or similar material, with the driver housing being plastic. The headband is covered by a thin cushion with the Dekoni logo printed on the top (away from you oddly enough). On top of the driver housing the aux cable is exposed on each cup. I personally don’t like this because I can see it easily getting nicked on something and breaking. The main aux. cable itself is detachable, which is ALWAYS a terrific thing to see (should be standard in my personal opinion). The cable is terminated on the headphone end with a locking 3.5mm male. and the source side terminated in a 6.3mm male but does include a 6.3mm-3.5mm adapter. There’s also little to no microphonics with it either. Rather when I was sitting and listening to them in my chair or walking around with the cord wrapped in my pocket, I never heard any rustling.

The pads, which is probably the focal point of these headphones, are of course interchangeable. There’s a small slit between the driver housing and frame where there’s just enough room to insert the pads. While you have the pads off you can get a really good look at the interesting diamond shaped planar driver that’s surrounded by a foam like material. Be careful when changing your pads for, at least for me, each time I did these foam pieces liked to fall out.

So overall, the Dekoni Blue is build pretty averagely and I’ve only 2 complaints to make, 1 major and one minute. The major one is that I really don’t like the exposed wire on the top of the headphones. Similar to that of the Beyerdynamic models, I just find them an unnecessarily high damage risk. The minute complaint I have is that the Dekoni name is printed backwards. When I demo a pair of headphones to someone they’ll often ask “how do I know which is left and right?” And I’ll usually tell them that if the brand name is printed on the top, if you can read the name, that’s how it goes on your head. Well, not with these, there is a L and R on the cups though.



The comfort on the Dekoni Blue is alright. I can, and have, worn these for several hour sessions but my ears do grow a little fatigued quicker than I’d like and I often find myself having to readjust the headphone on my ears. I believe my issue is with the headphone itself having a bit tighter of a clamping for than I particularly like because the pads (both Elite Velour and Elite Hybrid) feel great. I did find myself surprised that the really thin headband never became an issue for me.

To talk about the individual pads for a moment, the Elite Velour pads were a good bit firmer, to my ears, than the Elite Hybrid. Neither let the headphones driver rub against my ears but if you’re wanting a softer feel then the Hybrids will be your friend but if you like a firm/dense feeling pad then you’ll really enjoy the Elite Velours.



Coming into this completely blind I really didn’t know what to expect. I’ve listened to a fair amount of planar magnetic headphones so I had an idea but I was quite eager to finally hear what the Fostex T50RP (modded of course) was all about. My first impression when I listened to it was, not what I was expecting. The first thing I remember thinking when I heard the Dekoni Blue, w/ the Elite Hybrid pads, is that the bass is most certainly the focus on these and they’re fairly bloated with a predominant V-Shape sound. A good friend of mine likes them as a complement to his HD800 S, and I can definitely understand why, their very fun to listen to. Putting music aside for a little bit, I jumped onto Fortnite to see how they performed with gaming. To save a really long story, not good at all. The bloated bass is REEEAALLLYYY accented with the already bass forward sound effects Fortnite pushes which makes these not too pleasant and very fatiguing. The narrow soundstage also didn’t give me a good competitive advantage either.

How about movies and TV? Pretty nice honestly. Action movies sounded in your face and exciting. I watch a lot of anime (as I’m sure those of you who keep up with me are aware of haha) and when watching them with the Dekoni Blue, many of them do really well with the “fun” signature of the Blue.

Right quick, I’d like to touch on the power of the Blue’s. These are a 50ohm headphone with a 92dbl sensitivity. When I seen that I was like oh, these can be easily driven from my phone. I know planars really perform when given juice but these can be driven mobile. Well, though they can be driven, they max out my phone if I don’t have the preamp setting in my poweramp pro app maxed out. And there’s a lot of detail loss too. So don’t let the specs fool you. These really want some juice to perform their best. Do they need HE-6 power? SHOOT NO, but a desktop or competent mobile combi will do the job just fine. But let me talk about more of the individual aspects of the sound so hopefully I can convey what I’m talking about better.


The highs on the Dekoni Blue, I really can’t complain. They come through brilliantly clean and very sparkly. I never got the sense that any detail was being lost. I’ll use violins for an example. I got so much energy from higher toned music that I sometimes got chill bumps. A piece I’ve used several times is “A Moon Filled Sky” by Tenmon (many thanks to my friend @evshrug for finally identifying this artist for me). It’s such an emotional piece that has a violin front and center stage with a piano assisting it. The Dekoni Blue sends every single notes as high and as emotionally filled as if I was there in person listening to the piece. So, to my ears at least, I think Dekoni and Fostex did a great job with their treble. Now, if you switch to the Elite Velour pads, the treble does roll off a bit sooner than on the Elite Hybrids so you won’t get quite as high of an extension.


Most of the planar magnetic headphones I’ve listened to have each had quite impressive (forward) midrange. From all the hype and forums of other mods I figured that the Dekoni Blue would share that sentiment. Listen to the song “The Sound of Silence” by Disturbed. The vocals come through cleanly and, from what I can hear at least, accurately; but they’re way recessed. Also listen to “The Prodigy on an Acoustic Guitar” (kinda pretentious title but he is very skilled) or “The Last of the Mohicans” by Luca Stricagnoli. Both are very acoustic heavy pieces and two of which that enjoy very much. But the guitar’s recessed sound through the Dekoni Blue (regardless of which pad you use) just doesn’t bring forth the same calming enjoyment I get from these songs.

So though I don’t personally care for the midrange of the Dekoni Blue, I’ve also never been a huge fan of heavy V-Shaped sounding headphones either but I do understand their appeal, they’re really fun to listen to. I also, personally, couldn’t tell too much of a difference between the Elite Hybrid and Velour pads in the midrange.


The Dekoni Blue has a really interesting bass. And the way I describe it probably contradicts itself when reading it but it makes sense to me. But the bass has the same control and resolve that I’ve come to expect from planars but at the same time it’s bloated. Listen to the song “Freaks” by Timmy Trumpet, hear how the bass bubbles?

‘Umm, Firedawg. Timmy Trumpet and Freaks is hardly an audiophile song. It’s hardly mastered with any skill’

Well my completely made up arguer, you may or may not be correct, I was using a more extreme example that’s bass focused but fair enough. Also listen to the song “Love in the Dark” or “When We Were Young” by Adele (and though you can listen to them through the YouTube links provided I highly encourage a better source [especially with Adele, she's lovely to listen to]).

The bass in the Dekoni Blue’s aren’t bad, at all, they’re just interesting. Bloated may not even be the correct term but bubbles doesn’t really sound proper, but regardless, they still maintain that control and depth that planars are known for, ESPECIALLY when given proper amplification. Now, with the Elite Velour pads, the bass is toned down a bit. It still “bubbles” out, but not as much.



To summarize my thoughts on the Dekoni Blue. It’s certainly a fun headphone to listen too and it was nice to finally be able to listen to a Fostex T50RP product (that is actually the only model that Fostex actually makes themselves in house I’ve came to find out which is a pretty cool thing). I would’ve liked a more memorable unboxing but in truth I’m one of the VERY few people who actually care about such things. The design is also that of a “regular” headphone. Something I’ll do when I do go out in public with products I’m reviewing is gauge the reaction from people. It’s not uncommon that I’m asked about a headphone or complemented by how nice they look (and price isn’t a factor for I’ve had this with sub $100 headphones). But the Dekoni Blue’s/Fostex T50RP never got a single look from anyone, and I can see why, they look like a regular “mainstream” inexpensive headphone (look like, not is). Sound is something that I can see a lot of people liking but it didn’t quite do it for me. The sound has its moments but nothing I don’t think will make me remember them. I did however REALLY like the pads and would like to try them on other products.

Also, make sure to check out my unboxing and review videos. They’re pretty awesome AND you getta put a face to the Army-Firedawg name. If this review helped you out at all please hit that thumbs up button for it really helps me out a lot. Till next time my friends, stay safe.
Tony Jimenez
Tony Jimenez
Did the LG V20 power them enough? I was hoping a Fulla 2 would be enough.
Just started reading the review, awesome! I remember reading that Modhouse is careful to fix channel imbalance and other issues that plague the T50RP. Does anybody know if Dekoni's process includes selecting good units and correcting any issues? In other words, if somebody buys one of these how likely is it that he has a good pair with zero issues?
Oops, my comments are on all the reviews. Great job guys! Epic!