*Commercially available- I am not referring to the STAX 4070 or the closed back electrostatic headphone from Koss, both of which were not designed for commercial use.
*The content here has been pasted from the Head-Fi thread of the Kaldas INOX. Apologies for any inconsistencies in context or format, the images attached above go in between paragraph breaks.
What follows are brief impressions of my unit (SR-009, no pun intended) after using it over the course of the weekend.
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Before I start, I would like to express immense gratitude to the team at Kaldas and especially to Aumkar Chandan for not only being in constant touch and providing regular updates over the course of 10 months, but ***especially*** for accommodating to my situation in a manner I really didn't expect from a manufacturer in this day and age: Attached are email transcripts highlighting this particular conversation(in order-Please see Images 4,5 and 6).
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...With that, I was set to receive my unit by April end. It arrived yesterday, dispatching right on time as promised. It comes in a no-nonsense cardboard box with a felt lining and documentation specific to your unit, including an FR graph taken on a GRAS-45 head and torso simulator. (Image 7)
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As stated in earlier impressions on this thread (link posted below), I have to agree that the INOX has a very satisfying weight and heft. The quality of machining and tight tolerances are about as good as it gets.
In many ways, this headphone runs circles around the build quality of manufacturers like Hifiman and STAX. I believe Aumkar fully when he says, "No manufacturer is crazy enough to do this at a price point that is feasible". (Image 10)
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The housing of the earcups is machined from 316L Stainless Steel and the headband harp from Grade-V Titanium. The headband adjustment system is stiff but satisfying and you won't need to ever readjust it once you're set.
The headband cushion itself is comfortable and the headphone can accommodate very large head sizes. For reference I use the HD800S 5 out of 7 notches on each side and here I'm barely at 3 out of 9 or so notches. There is so much space that I can use a tall ZMF comfort strap and still have room to spare.
The earpads are snug and the velvet lining on the inside can touch your ears lightly. The clamp force is medium.
The comfort is an 8/10: It is a heavy unit, but not unreasonably so and the ergonomics are excellent which makes up for its weight on your head.
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The build quality is a solid 10, no question.
It is one of those things that wouldn't immediately catch someone's eye when they enter your room, but they would definitely ask about it once they get to hold it in their hands. It has an unmistakable industrial design and looks deliberately handmade and high-end. It's one of those headphones that a listener would take seriously before even putting it on their head.
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While describing sound, I like to refrain from using generic terms like "musical", "organic" or "analytical". Instead, I try my best to give context behind what I'm hearing.
My chain is as follows: Windows PC (Bit perfect local playback using HQPlayer, Jriver media player and lossless streaming using Apple music)>Denafrips IRIS DDC>Denafrips Pontus 15th (using Coax)> KGSShv Carbon.
INOX tested with the bass ports "open".
Right off the bat, I am going to say two things:
-This headphone sounds unmistakably like an E-Stat.
-This headphone sounds unmistakably closed back.
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Translation:
The bass has very good extension but is more heard than felt.
It outlines the starting and stopping of bass notes in a way that only an E-Stat can manage.
The bass conveys excellent rhythm and speed, but true to the E-Stat format it lacks body and slam.
*This is not a con, but rather a known trade-off with E-stats...
-You gain unmatched transient response but lose slow driver inertia due to the diaphragm being very low mass.
-Bass frequencies occurring naturally rely on reverb trails to convey body and texture.
-The INOX does not escape that trade-off.
Second, on the point of sounding closed:
E-Stats are known to be "light" and "ethereal" sounding. I realised this is due to a combination of being "open-back" and "massless".
What does "closed-back" get you then?
-The same effortlessness to the sound.
-A better imaging lock.
It is similarly lightweight, but not "ethereal".
-A denser soundstage, with a more convincing placement of instruments.
-Defined instrument boundaries, not "hazy" or "vague" like open back E-Stats.
-More convincing depth. (Instruments sounding layered, one behind another)
-Sounds closer to the ears with roughly a medium, circular sounding stage.
-The STAX stage is flatter and wider, more diffuse.
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On the technicalities, it should be up there with the very best.
While I don't have a TOTL E-Stat on hand, I can say it comfortably goes toe-to-toe with the 007A and edges out the Hifiman HE1000SE purely in resolution.
With the ports open, the tuning is Harman"ish" but more V-shaped (Recession at around 500hz)
With the ports closed, it's a straight bassline which I found too lean with the E-Stat driver type. You may prefer closed ports if you listen to classical.
In a nutshell, the headphone is technically as capable as a TOTL E-Stat and your taste dictates whether or not you like the Harman tuning.
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Coming from The Stax SR-007A, I found the upper midrange emphasis a bit jarring at first but got used to it over a few hours.
I use a lower volume with this headphone than on the 007A but I don't feel as though I'm missing anything.
Both tunings are very different; they highlight different parts of the music.
With open ports, the INOX sounds decidedly V-shaped with emphasis on sub-bass and around 3khz.
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Subjectively:
I personally outgrew this type of tuning with age to prefer warmer tilted and midrange neutral tunings not only for vocals but for all kinds of music (including EDM).
I feel that driver placement and design of the acoustic chamber are far better determinants of soundstage than sucking out mids (typical Harman) but that is a very subjective take.
This is in no way a knock against the headphone.
It is a fantastic piece of engineering that will stay on my desk alongside the SR-007A and the HD800S.
In any case, EQ is always an option.
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Finally, on the point of EQ I should say it that this headphone is more power hungry than the 007A.
I have been explained by Aumkar that this is due to using a physically smaller diaphragm than average and the challenges of being closed back: To move air where you want it to go.
He recommends a minimum of the STAX SRM-353 for this headphone and based on my experience I would say so too.
That about covers everything I could gather in 24 hours.
Please feel free to ask anything else you might want to know.
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I am in touch with Aumkar and we are trying to get an interview alongside the first video review of the INOX.
Will keep everyone posted, thank you for reading!
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Head-Fi Thread:
Technical Analysis(worth a read):
INOX (Technical Analysis and Release Report) – Kaldas Research