Koss ESP-950 Vesper Pads Review and Measurements

Discussion in 'Headphones' started by Marvey, Jun 9, 2021.

  1. Marvey

    Marvey Super Friend

    Staff Member Friend BWC
    Joined:
    Jun 6, 2021
    Likes Received:
    1,387
    Trophy Points:
    93
    A while back, there was a request from some members for me to obtain and test these pads. (As an aside, I have noted the requests and will do my best to get to all of them. Just give me time. And by time, that could be months or even a year!). A shout out to FongAudio.com who has helped make this happen. What I have on hard are two versions of the hybrid suede pads. The hybrid pads are wrapped in leather with the surface that rests against the head suede leather. The insides are soft memory foam. One pad looks to be angled, the other is flat. I will compare these to the Drop ESP/95X pads. The Drop pads are velour with a foam which is a slightly stiffer. I find all three pads preferable to that of the stock ESP950 pads. Here are the three sets of pads lined from left to right: Vesper hybrid, Vesper angled, Drop ESP/95X. Note that the ESP/95X pads are mounted on the earcup of the headphone.

    DSC02580.JPG

    Let's start with simple frequency response. Note that the sharp narrow dips in the lower treble and high treble are measurement artifacts (to be confirmed in CSDs in later post.) The Flat Plate Coupler was used here to get the most consistent relative results.

    Drop x Koss ESP/95X with 95X pads
    Flat Plate Coupler
    upload_2021-6-9_20-8-27.png

    Drop x Koss ESP/95X with Vesper Suede Pads
    upload_2021-6-9_20-9-1.png

    Drop x Koss ESP/95X with Vesper Suede Pads / Angled
    upload_2021-6-9_20-11-56.png

    The FR measurements support my subjective observations. The stock 95X pads were mid-centric and laid back. The Vesper pads seem to have less emphasis in the mids while lifting the presence area with the slanted versions being the most flat sounding from the lows to mid-treble. As such, they are a bit brighter and less laid-back. Subjectively regular hybrid Vesper is arguably the smoothest in the highs. The slanted versions are close, have even smoother mid-treble, but at the expensive of some tizz just into the air region. The slanted versions also have more room inside the cavity, thus present a more open headstage.

    I will post CSDs in a bit as I feel the are more reflective what we hear in the midrange to highs compared to only frequency response plots.
     
    • Like / Agree Like / Agree x 10
    • Epic Epic x 3
    • List
    Last edited by a moderator: Jun 9, 2021
  2. Marvey

    Marvey Super Friend

    Staff Member Friend BWC
    Joined:
    Jun 6, 2021
    Likes Received:
    1,387
    Trophy Points:
    93
    95X Pads
    CSD ESP950 95X pads.jpg

    Vesper hybrid pads
    CSD ESP950 Vesper pads.jpg

    Vesper hybrid slanted pads
    CSD ESP950 slanted Vesper pads.jpg

    Both of the non-slanted pads have a greater dip in the upper mids. The Vesper (normal) is just slightly less dipped and has the smoothest low to mid treble. The Vesper angled pad is the flattest throughout, until the well defined peak at ringing just under 12kHz. Fortunately, ridges here are much less annoying, at least to me, than between 6-9kHz.
     
    • Like / Agree Like / Agree x 7
    • Epic Epic x 2
    • List
  3. Marvey

    Marvey Super Friend

    Staff Member Friend BWC
    Joined:
    Jun 6, 2021
    Likes Received:
    1,387
    Trophy Points:
    93
    Burst responses.

    95X pads
    B1696 ESP950 95X pads.wav_burst.jpg

    Don't worry too much about the big spike on the first sine wave in the burst. The Audeze LCD-2C and Grado RS2 had this effect. It's overshoot and I think reflective of some "fast" headphones. What is interesting is that I didn't get this amount of overshoot with the freebie Koss amp. This result came from iESL -> Vidar. Would be curious to go back because the iESL -> Vidar does sound less limp than from the Koss amp.

    Now I would be more worried if there was a dump at the 2nd cycle of the 4800Hz attack. This typically results in some timbral oddities: glare, prickliness, grain, etc. Good thing there isn't.

    Vesper Hybrid
    B1696 ESP950 Vesper.wav_burst.jpg

    Vesper Hybrid Slanted
    B1696 ESP950 Vesper Slanted.wav_burst.jpg

    The Vesper pads are more controlled, but this could be the result of the material, the leather, which helps with dampening.

    Update: the bass sounds more solid and tighter on the Vesper pads. (Patricia Barber - Company, Daft Punk - Doin' It Right). I don't know if this is reflected well in the attack and decay envelopes. With the 95X pads, we can see just the tiniest dip at T = 3 to 5 for 50Hz for the attack envelope. The 50Hz decay also lingers bit longer compared to the Vesper pads. Do these mean something? We really need more data to see if there is any correlation to what I am hearing.

    upload_2021-6-9_22-10-2.png

    upload_2021-6-9_22-10-40.png
     
    • Like / Agree Like / Agree x 10
    • Epic Epic x 3
    • List
    Last edited: Jun 9, 2021
  4. AllanMarcus

    AllanMarcus Friend

    Friend
    Joined:
    Oct 23, 2015
    Likes Received:
    2,502
    Trophy Points:
    113
    Location:
    Los Alamos, NM
    Home Page:
    Thanks
     
    • Like / Agree Like / Agree x 1
    • List
  5. rhythmdevils

    rhythmdevils Best SBAF member of all time

    Staff Member Friend
    Joined:
    Apr 15, 2020
    Likes Received:
    4,029
    Trophy Points:
    113
    Location:
    Bay Area
    Very cool Marv!
     
  6. Hands

    Hands Overzealous Auto Flusher - Measurbator

    Staff Member Friend MZR
    Joined:
    Sep 27, 2015
    Likes Received:
    11,976
    Trophy Points:
    113
    Location:
    Colorado
    Home Page:
    I got a 95X within the last few months and am not too thrilled with it. I would go so far as to say it's one of the most unpleasant headphone listening experiences I've had in a while.

    Even after accounting for placement, fit, seal (or even purposeful break in seal), I find them to sound bright as hell no matter what I tried. Seriously, I'd rather listen to a stock HD800.

    Whatever measurements tend to (consistently) show with the 950/95X, that's just not at all how they sound on my head.

    Now, given how sensitive these are to fit and seal, I would not be surprised if this is just a case of it not working right with my noggin and/or ear geometry. It happens.

    I found the leather Vesper pads to exacerbate the brightness over the stock, velour 95X pads. But they do improve tightness and focus, I guess.

    However, I did find some success in doing the following to the stock, velour pads:

    1. Taping over the two holes on the underside of the pads.
    2. Wrapping electrical tape around the side of the pads (outer wall, so to speak).
    3. Taping over the area where the pads slip into the headphone enclosure.

    The goal here was to minimize leakage around and under the pads. Think something akin to the common hybrid pads you might see.

    This made them sound decent to me.

    For the Vesper pads, mine have a ton of holes on the underside. Even after taping around where they slip into the headphone enclosure, they still don't sound right. Wondering if I need to seal off some of those holes. But am not sure the headphone will sound good if using totally sealed pads.
     
    • Like / Agree Like / Agree x 4
    • List
  7. M3NTAL

    M3NTAL Friend

    Friend
    Joined:
    Sep 27, 2015
    Likes Received:
    767
    Trophy Points:
    93
    Dang - why punish yourself modding something from such unpleasantness to just barely decent? Sounds like a lost cause. I wonder what type of mods would work for people that the headphone seals well with.
     
  8. Marvey

    Marvey Super Friend

    Staff Member Friend BWC
    Joined:
    Jun 6, 2021
    Likes Received:
    1,387
    Trophy Points:
    93
    I suspect it's a lost cause for you based on geometry - that is your head and ear (pinna, concha) interface with the pads and internal cavity. The ESP950, regardless of pad, I've found to be relatively easy to get a good seal on any of my couplers - that is I don't even try.

    Here is a measurement of what happens when I very intentionally pop the seal by shoving a rag at the corner of the earpad to raise it.

    Drop x Koss ESP/95X with Vesper Suede Pads
    YEL = normal seal
    GRN = intentionally leaky seal
    upload_2021-6-10_22-37-11.png

    We actually get moar bass from 50Hz to 90Hz with the same bass extension until we hit 35Hz where it then rolls off faster. This is actually better bass extension than most speakers, even very expensive audiophile speakers.
     
    • Like / Agree Like / Agree x 4
    • List
  9. Hands

    Hands Overzealous Auto Flusher - Measurbator

    Staff Member Friend MZR
    Joined:
    Sep 27, 2015
    Likes Received:
    11,976
    Trophy Points:
    113
    Location:
    Colorado
    Home Page:
    Why? Curiosity. Also, I become very stubborn when angry. :)
     
    • Like / Agree Like / Agree x 5
    • List
  10. Degru

    Degru Facebook Friend

    Joined:
    Jul 22, 2017
    Likes Received:
    133
    Trophy Points:
    33
    Location:
    Portland, OR
    I'd be curious of the effects of Vesper pads on Stax; I've found all Lambdas to be extremely sensitive to (OEM) pad changes, which is annoying because Stax does not make the actual stock pads for some of the better old models e.g. Lambda Signature, 404LE, anymore, instead offering the EP234 and EP507 pads as replacement (2/3/407, 507 stock pads).

    I was skeptical of Vesper pads as being something prioritizing comfort without enough care for tuning, but perhaps they may actually be worthwhile as Stax isn't exactly offering anything better.
     
  11. spoony

    spoony Spooky

    Friend
    Joined:
    Sep 28, 2015
    Likes Received:
    494
    Trophy Points:
    63
    Hands
    Overzealous Auto Flusher - Measurbator - Sensitive Flower
     
    • Like / Agree Like / Agree x 1
    • List
  12. Hands

    Hands Overzealous Auto Flusher - Measurbator

    Staff Member Friend MZR
    Joined:
    Sep 27, 2015
    Likes Received:
    11,976
    Trophy Points:
    113
    Location:
    Colorado
    Home Page:
    What about sensitive brown star?
     
    • Like / Agree Like / Agree x 1
    • Epic Epic x 1
    • List
  13. M3NTAL

    M3NTAL Friend

    Friend
    Joined:
    Sep 27, 2015
    Likes Received:
    767
    Trophy Points:
    93
    It was a pretty big deal when the ESP950 finally started coming down in price. The entire system at $450 has always seemed like a great foot into the electrostat world. I haven't had a chance to hear the Nectar stuff, but I have owned Stax and had a good amount of time with the Voce. And for me - none of them are ever going to be an island paradise headphone, so pick one that is un-offensive out the box at a good price. The 950/95X is pretty dang solid. Hands hyperbole is a bit extreme unless he has an ace up his sleeve with a system at $420 that blows away the $450 95X.

    I'm not sure why we are poo-poo'ing on so many things without actually just saying - don't mod this thing and lets get some better QOL and force the manufacturer into making it correct. If they can't do that, quit helping them sell shit with the promise that mods will solve their lives issues one sheet of TP at a time.

    Throw that 950 into your smoldering HD560s fire to appease the headphone gods.

    My post is meant in jest, but seriously guys - you alright?
     
    • Like / Agree Like / Agree x 1
    • List
  14. Armaegis

    Armaegis Friend

    Friend BWC
    Joined:
    Sep 27, 2015
    Likes Received:
    4,988
    Trophy Points:
    113
    Location:
    Winnipeg
    Each end of you can have its own separate title...
     
  15. Hands

    Hands Overzealous Auto Flusher - Measurbator

    Staff Member Friend MZR
    Joined:
    Sep 27, 2015
    Likes Received:
    11,976
    Trophy Points:
    113
    Location:
    Colorado
    Home Page:
    I can assure you the way I described my experience with the 95X was no hyperbole. It legitimately sounded like a treble-heavy disaster to me.

    Again, my best guess was a peculiar interaction with my own head/ear geometry, even after accounting for fit and seal (as best as is possible on my head).

    It's possible I'd get along better with the stock, pleather 950 pads. I liked the 95X with some basic pad mods.

    Since I'm well aware I'm an outlier with my experience, I don't see why there's a need to pressure the manufacturer necessarily to improve or change anything.
     
  16. M3NTAL

    M3NTAL Friend

    Friend
    Joined:
    Sep 27, 2015
    Likes Received:
    767
    Trophy Points:
    93
    @Hands - thank you for the reply and I'm sorry if I was on the attack. I respect you and how important your thoughts are. I align more with you on tastes than some tastes of the others. I just personally can't be mad at my experiences with the ESP950 compared to how much I've spent (time+money) in the electrostat world. So that's the reason I was going for the tread lightly sentiments.

    They are my electrostatic compliment to the hd800 - so you aren't saying anything new with regards to the tonal signature, but dang - you just did a hell of a compliment to the ESP950 at 1/3 price of the HD800 and not requiring another piece of matched gear (E90).

    As soon as @n3rdling provides us with the second coming, we just have to bid our time as there aren't many options, so I'm all for this janky Koss USA product at a price that went into deflation instead of inflation like some places called HiFiMan land.

    /Rant over (apologies Hands - I just respect you enough and feel like you are influential enough to this forum to get everyone to just write off the ESP950 when I don't think it's really all that bad.)

    LOL why am I standing up for my janky headphones LOL... .I really need to get my eXstata working correctly and try out the Nectar phones and see what's new. The Voce wasn't enough to get me back in the game and the 009 went the wrong way all together. Susvara in there bridging gaps and building walls at the same time.

    Cheers & Beers (apologies for my stubbornness - I need a work vacay asap)
     
    • Like / Agree Like / Agree x 3
    • List
  17. Marvey

    Marvey Super Friend

    Staff Member Friend BWC
    Joined:
    Jun 6, 2021
    Likes Received:
    1,387
    Trophy Points:
    93
    I'll do a full distortion analysis of the ESP950 and follow up with a full set of Nectar Hive measurements which I didn't have a chance to take before I suddenly decided to move to TX.
     
    • Like / Agree Like / Agree x 1
    • List
  18. Hands

    Hands Overzealous Auto Flusher - Measurbator

    Staff Member Friend MZR
    Joined:
    Sep 27, 2015
    Likes Received:
    11,976
    Trophy Points:
    113
    Location:
    Colorado
    Home Page:
    Oh, no problem at all, and you make fair points. I was only sharing how perplexed I was on hearing the 95X. It really shouldn't sound the way it does to me based on tons of other user experiences and measurements. And, yet, it does.

    It's kind of like how some, depending on their genetics, find cilantro to taste like soap. Doesn't mean anyone else should stop using or enjoying cilantro. More of a peculiarity than anything else. And I think there are mountains of evidence to suggest the 950/95X are headphones almost everyone should give an honest try at least once.
     
  19. Marvey

    Marvey Super Friend

    Staff Member Friend BWC
    Joined:
    Jun 6, 2021
    Likes Received:
    1,387
    Trophy Points:
    93
    Cilantro does not taste like soap. I take umbrage at this!

    I am wondering if the leading edge, as seen in the burst envelopes of the 1.5kHz and 4.8kHz bursts is what you are finding annoying. Frequency response doesn't explain everything we hear.
     
    • Like / Agree Like / Agree x 2
    • List
  20. M3NTAL

    M3NTAL Friend

    Friend
    Joined:
    Sep 27, 2015
    Likes Received:
    767
    Trophy Points:
    93
    Interesting observation. It looks like the angled vesper pads might help out. Are the 95X pads to blame for that edge in the burst? I think you've done stock 950 measurements - I don't remember if that was there also?
     

Share This Page