What did they do to the sound?
Same here. I would love to try out all the options; especially custom pad thickness.
Anyone with a 3D printer try making spacers for the earpad/cup to see what it does sonically? I know someone did that for stax and the spacing makes a big difference.
As of my last post here, I hadnât heard these in a few weeks. Now, I havenât heard them in about three months. I got my replacement set and canât wait to get them going tomorrow!
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Been a sec since I got them and did a comparison, looking at it tonight. 
Sorry yaâll.
EDIT: So most open is the velours they come with then vesper then Dekoni. Comfort is Vesper, then Dekoni, then velour just due to scratching. Seal is very good on vespers so driver flex can be heard much easier. Also benefits from low end punch, but overall volume is reduced due to absorption in the pads. Dekoni pads are very intense in mids and make the sound more harsh to me overall. I have used them less overall due to their intensity of sound. Honestly I would use any pads on these cans, but from what I have I switch back and forth with Vesper and stock pads. Dekoniâs get use, but not often since I prefer the others. Highs dont seem different. Bass is Vesper, Dekoni, Stock. Just EQ the stock up for the best experience honestly, unless you want the perfecto and EQ with vesperâŠrisking some driver flex.
Recipts LOL
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I had a pair of 2 + 2âs years agoâŠ
I have been running these for a few days now. I find the stock system thin and so I run it with a Schiit Loki EQ.
It has been a few months since I heard this system. So far, even with the Loki, it sounds weak. First off, it is far from crystal clear. I even turned off the Loki to see if that would help. It didnât. It is like sparkle.
Next impression was a Massive lack of bass. I even turned the Loki up to max and still nothing.
I know theyâre not known as rock 'phones but I was going through an alt rock playlist and it just didnât sound right. I decided to power up my Violectric amp and plug in my Senn HD660âs. The difference was AMAZING!
The HD660âs sounded like Fostex 900 MKIIâs, in comparison! I am sure a lot that was the amp, but the amount of bass was shocking.
The Koss system sounds much weaker and thinner than I remember from the spring. Or maybe I am just spoiled from recent acquisitions (Sundaraâs, Elexâs, HD660âs, Liquid Platinum and Violectric V220). I shouldnât rush to a decision, although if I had just bought these, I would be returning them.
I actually tried trading them today to a couple of guys on CAM selling interesting headphones. 
This is probably the only post you will ever read where someone called any Senn headphone a bass monster! 
I will post back in a few weeks with final thoughts.
PS: The 660âs keep surprising me.
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Curious, has anyone removed the front foam from the inside of the earcup as a mod? Would there be a sound change or is it acoustically transparent?
i wanted give my experience with the Koss ESP/95x
i purchased one as part of the first batch on Massdrop, received it a couple of months later. and fell in love with the detail, and how light they were.
few months down the line i started getting a humming noise, did some tests but couldnât get rid of it. so i contacted Massdrop, who suggested to ship it to Koss directly, and they will refund the cost of shipping (Abu dhabi).
few months later koss replaced it and life was back to normal, till it broke again. this time i asked for a refund from Massdrop and sent the unit back.
Iâm not sure what caused it , power here is very stable. so Iâm guessing it was just the energizer or the wall wart. koss never did tell me what had gone wrong.
my advice to anyone who is planing on getting these, Go for it, they sound great and if you live in the US you can easily make use of the lifetime warranty, without having to pay high shipping and customs.
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Sorry you ran into a problem, I know I have had some issues too, but with me I know my wall power is not the best, so when not in use I turn off the energizer and unplug the headphones, doing this has prevented any hum after I first noticed it. Electrostatics can be a bother but god if I donât love the sound!!!
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Electrostatic headphones/speakers are very sensitive to dust. The reason for humming noise or other weird stuff couldâve been that.
Even if one cares about them like jewel, after some years they need to get cleaned up.
IMO dynamic headphones are the best because theyâre way more dust-resistant.
i kept mine unplugged when not in use, im not sure about the dust, the first pair was less than 6 months old, and the replacement had the same issue within a month. i guess i have bad luck with electrostats.
all my other headphones work just fine, Ive even dropped my 6xx a several times, that thing is plasticky but built like a tank.
ill give them a try again once my wallet fills up
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Second day since purchase, and experiencing a slight squeal in the left that gets worse the longer I used it. I tried tapping, no change.
Than I read a post in the Drop discussion in which the person suspected it was due to humidity/moisture from his head. After reading, I gave the headphones about a minute off my head. Squealing is still there but it got significantly better. Another 10 minutes of my head and itâs gone.
Such a peculiar headphone.
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Also, use a light clean fabric, plastic bag , glass case or box of some kind to keep them covered and free of dust And pay particular attention to keeping hair of any kind from getting caught up in the drivers. This is true of all electrostatic drivers but these in particular I have read posts elsewhere of dust and hair causing noises toođ
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Alright, itâs been 1 week since I had these. Absolutely love them. Here are my impressions so far. These are the same that I posted as my Drop review:
For several months I have been looking for a ~$300-$500 headphone I could call my endgame. This hobby has been digging into my pockets more than I want, especially considering I have hundreds of dollars worth of CDs than I want to collect as well.
With the Porta Pros, I was surprised how satisfied I was with the sound of something I only paid $20 for. More so than my ATH-M40x and ATH-AD900x. As much I would want to pretend to be a snobby audiophile who canât listen to anything less than âHi-Fi,â my ears are not very picky. I also gave the other Koss 60 ohm on-ears a listen (kept the KTXPRO1 as well) and concluded what I want from most from an endgame headphone is not necessarily âbetterâ sound, but âdifferentâ sound.
That brought me to the ESP/95X. There are a lot of great headphones at this price point, maybe even better, but this Koss is the only ready-to-go electrostat under $1K new. And different it is.
Below are my sort-of stream-of-consciousness impressions on the device. I had a hard time writing organized impressions for this, but I hope this is enough to give a sense of how much I like these headphones. If you are even slightly interested in electrostats despite their inherent flaws, the 95X is absolutely worth the money.
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Tonality is nothing special. Itâs mid-centric. Even so, the relationship between mids and bass/treble is not emphasized/recessed. Itâs more like core and supplement, primary and secondary. In otherwords, the bass and treble still are very adequate and are not overpowered by the mids. The sound signature overall feels natural to me. From the very first second, I found it quite agreeable even though my ears were heavily acclimated to the Porta Proâs warm signature.
The real uniqueness of the headphones has to do with everything else.
Detail retrieval and resolution is phenomenal. An analogy: My Porta Pro is like looking at a photograph of a statue. The post-processing is excellent and the photo is overall lovely, but you canât see the fine texture and shine off of the marble. My ATH-AD900x is more kin to seeing it in real life â but there is fence surrounding the statue so you canât get closer. You still get a pretty close view and can see the rough patches, the cracks, and all those subtleties in the statue. The ESP/95X is to not only be able to look at the statue as closely as you want, but also feel it with your hands. Brushing your hand across the statue, you can feel every small bump and recess in the otherwise smooth marble. The limit is your own perception.
There was so much new to unpack in music I was familiar with â a tone I thought was flat actually has a little bit of vibrato, a page flip in the middle of a rather loud section for full orchestra, etc.
As someone who used to play violin, the amount of information I was able to piece out from timbre alone really blew my mind â unlike with other headphones, I was able to discern the difference between notes of the same pitch played on the A string versus the E string. I could hear the bow bounce on the string. I could hear the difference between a slurred sequence and a non-slurred one. In one song, I realized the instrument I thought was a violin with very warm strings was actually a viola from timbre alone. I was able to confirm this by the fact the player played E3, a note too low for violins. Maybe I subconsciously processed these things with other headphones, but with the 95X I was able to consciously pin-point each of these subtle details.
Transient response, the âspeedâ of the headphones, is also ridiculous. Percussive sounds like cymbals and snares are so unbelievably crisp and energetic while bass drums and toms are super tight and controlled. Drum rolls are not a vibrations but full strikes. I thought the AD900x had tight bass, but the 95X is even more accurate AND intense. The 95X is such a perfect match for speedcore. Things in excess of 1000bpm come out with such unbelievable clarity and tightness that my other headphones cannot reproduce.
Separation is excellent as well. Even in poor mixes where voices are not well balanced, itâs easy to pick out the recessed timbre. Even in complex pieces with dozens of voices, each and every one can be tracked.
I often catch myself critically listening to microdetail even when I donât mean to. Heck I did just now while writing this. There is just such clarity that it feels impossible to truly appreciate these headphones without giving the music all my focus. Every evening since I first used this a week ago, I took them off thoroughly impressed with the experience.
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There are several large flaws to the 95X. Dealbreakers for some people.
Though the bass is accurate sonically, it lacks a lot of impact. Loud bass such as the tubas or cannons in 1812 sound flat because these drivers just cannot do strong bass like a dynamic can. Bass drums donât have a âphysicalâ kick to them. Contrabass in jazz does not produce the kind of warm vibrations you can feel as much as you hear. At worst, these headphones feel very clinical and uncolored due to impressive technical ability contrasted by a lack of âfeel.â Sometimes the sound feels ephemeral and thin due to the lack of a full-bodied bass, but it isnât necessarily a bad thing. This slightly âghostlyâ presentation is fitting for how agile and light the technical aspects of the sound are. Personally, I find this quirk due to the electrostatic design to be alright since the sonic quality is so good. Stuff like hardcore is still very listenable and energetic despite not having bass thump â most of the energy comes from how well the mids and treble shine.
The build is also pretty cheap for something priced at $500 (let alone $1000 for the ESP950) but is no means bad. All the materials feel âbudgetâ like those on the cheaper Koss, but fit and finish is very good. Comfort is also quite good â Large cups, velour pads, a well-padded headband, and light weight all allow this to be an all-day sort of headphone. Worst part about the build is that the foam protection behind the pads are really noisy. They crinkle a lot when your ears brush against them (they will unfortunately unless you have very flat ears), but it hasnât been too bothersome really.
People complain about the dual volume knob (sorry, âacoustic levelâ dials), but I donât mind it at all. There are indents to judge knob positions relative to the other, and turning both up or down is as simple as gripping both with one hand. My left and right are well balanced, but I turned up the left slightly because my left ear is worse than my right.
The largest flaw is how noisy the headphones are, specifically the drivers. No real dust protection and very, very Koss-quality build can mean a lot buzzing and squealing in one or both drivers if youâre unlucky. My left driver is a bit troublesome with intermittent noises. Itâs very quiet and masked by audio playback, but itâs quite annoying in silence. Below I recorded about one weekâs worth of issues. I really envy those who have perfect drivers, but at the same time I feel my issues are not worth claiming warranty over just yet. Honestly frustrating, and does ruin an otherwise sublime headphone.
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Issues:
Day 1: Slight squealing in the left after a long listening session. Inaudible with music.
Day 2: Squealing still there. Intensity and timbre change and noise sometimes disappears completely.
Day 3: Complete silence.
Day 4: Started up silent. No squealing anymore in the left, but an intermittent buzzing/ticking/croaking sound developed within 10 minutes. A bit louder than the squealing but less frequent. Tapping the side of the headphone makes it go away for a couple seconds.
Day 5: Buzzing became more persistent. Took off the pad and blew some air. Nothing changed for 10 minutes, but then the issue resolved spontaneously. Silence again. 
Day 6: No use because I was too busy.
Day 7: Dead silent for the first two hours, then some very slight croaking and buzzing. Went away after a couple minutes.
Day 8: Quiet on startup. Slight croaking a minute in but much quieter than other days. Crazy idea, but maybe it actually is due to the foam under the pads pressing against the driver. My left ear does press against the foam than the right. If I give some time off my head the sound seems to get a bit better. Oh well.
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Nice review!
Your review just made me put these back on my headâŠi wanted to sell them to fund future purchases, but i think i might seel my Audeze and not these. I listen to lots of electronic music, mainly breakcore and jungle which have obviously very fast drums (snaresssss) (especially breakcore, it gets a bit messy sometimes :D) and these really displays every piece of the music at insane speed. And i feel that the sound is just coming out of nowhereâŠ
And i agree that the bass, even tho its lacking, fits well into the overall sound of the Koss and even bass heavier music is quite addicting on them. Feel you on that !
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So not to shill, but Vesper pads help to seal more and get a little more bass out of the cans, plus comfort is good too. I think they are better than the Dekoni pads, but I think the vesper sounds closer to stock as far as open-ness while also getting just a bit more punch. If you plan on keeping them like me invest in some extra pads to see what you like. 
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These ones looks comfy as hell!
Which do you have?
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I have the ones you linked, they are the hybrids, best as I can tell they work good due to the Alcantara(maybe suede) is in the bottom and the top of the pad so it absorbs some of the sound and doesnât reflect the same way the Leather perforated Dekoniâs do.
Nice, how much is the hybrid pad? Looks really interesting, i had vesper on my list a while back but forgot about them. Probably hard to get or very expensice since im in europeâŠ
Here is the link again, Mon said it in a post year ago. Not cheap, but much love! https://fongaudio.com/store/default/headphones-31/headphones/headphone-accessories/koss-esp950-custom-replacement-pads.html
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