Hugely improved balance across the spectrum, Much improved mid-bass response, More detailed and open treble, Improved soundstage depth, More comfortable and better quality feel
Slightly more diffuse bass impact
Yaxi’s ESP/95X earpads are a very smart upgrade for current users and something to consider for buyers on the fence about dipping their toes in electrostatic headphones on a budget.
Dip your toes deep enough into the audiophile scene and you will likely start to hear mention of electrostatic headphones. Lauded for their lightning fast drivers delivering the pinnacle of detail and acuity, the hopes and dreams of many are quickly shattered when they find out how cost-prohibitive this pursuit can become. Drop challenged this notion with their re-release of the famous ESP/950 in the form of the ESP/95X. This is an electrostatic headphone system plus energizer all for under $500 USD. However, though it does offer a taste of the electrostatic experience, many have found that the frequency response leaves much to be desired, especially when it comes to bass response. Who better to address this than Yaxi, Japanese earpad extraordinaire. These guys are making some of the best pads in the game, all purpose built for a particular headphone based on popular feedback.
The Koss ESP950/95X pads retail for $59 USD. You can treat yourself to a set on Yaxi’s webstore.
I would like to thank Mia from Yaxi very much for her quick communication and for providing me with the ESP950 ear pads for the purpose of review. I conducted a paid photoshoot for Yaxi, however, all words are my own and there was no incentive for a positive review. Also taking into account that I received the pads free of cost, I will attempt to be as objective as possible in my evaluation.
The stock earpads are reminiscent to the stock Sennheiser HD6XX-series headphones, being comprised of foam-stuffed velour. It’s fuzzy and feels like it would wear well over time, however, the firmer padding is not the most accommodating of facial anatomy and the synthetic surface doesn’t breathe as well as I’d hope. The Yaxi pads are an immediate step up in quality and will be familiar to anyone who’s purchased their pads for other headphone models. In terms of dimensions, they are about the same here so if you would prefer more width from the stock pads, you won’t get that from the Yaxi pads.
Otherwise, they impress with a slightly firmer plastic surround that achieves a better fit on the mounting plate than the stock pads, alongside a much more robust pleather/alcantara construction. This material choice delivers a much more supple in-hand feel in addition to being far more breathable over long-term listening sessions. As before, Yaxi showcase superlative attention to detail with high-quality, perfectly even stitching, providing an immediate jump up in perceived quality. The heat-activated memory foam padding conforms to individual head shape, alleviating hotspot formation and enhancing the seal. I think this is ideal in terms of the sonic performance too, aiding bass response – but more on this later.
In the interest of fairness, I will be evaluating the headphones without eQ,. This will simply be a comparison between the two pads. In their stock form, the ESP/95X is a lean headphone with a rather heavy midrange focus. This is to be expected to some extent on any electrostatic headphone as this driver type struggles to reproduce deep bass tones. However, while I feel the midrange itself sounds okay here, it is lacking a lot of gusto due to the heavy bass roll off. It is tonally clean but very light-footed in the bass, further exacerbated by its quick note presentation, and has a notably dry and boxy voicing in the midrange. My main complaint here is the lower-midrange bump that attempts to compensate for its lack of bass and does minimise midrange thinness though at the cost of timbral accuracy. The top-end is smooth and laid-back which prevents it from skewing into brightness and fatigue. However, it also means the headphones sound a little detail deficient at times as treble can be overshadowed by the midrange.
Switching over to the Yaxi pads, I immediately like what I’m hearing much more. The changes fall in line with what I’d want for my personal preferences and, more importantly, what I think most listeners would enjoy. Bass most noticeably is brought forward, and while it still isn’t especially well-extended, you now get a good mid-bass punch and fullness. This works much to the benefit of overall balance, depth and midrange timbre too. While doing some separation and tonal cleanliness is sacrificed, no longer does the headphone sound quite so lightweight and dry, achieving a far more coherent presentation. The midrange now carries a light warm tonality and sits just in front of the mid-bass, no longer dominating the presentation. The top-end has a little more snap in the lower-treble especially and appears to have been brought up overall in almost equal measure to the bass. As the sound remains mid-forward, it doesn’t sound remotely sharp or intense. Overall, a much more balanced presentation that is far from perfect but much easier to appreciate.
Extension is immediately improved, and the mid-bass especially is brought forward by a moderate degree. Fear not, for the ESP/95X is a headphone that was severely deficient in factory form, lacking bass slam almost entirely and being very light-footed through the mid-bass too. So, rather than converting these to bass canons, you receive a far more fleshed out and well-rounded presentation that achieves better balance overall. Mid-bass now has a good amount of punch and kick, albeit sub-bass slam, pressure and rumble are still mostly absent. The bump through the mid-bass and slightly more present upper bass does mean you get a more accurate note timbre and a little more texture.
In the grand scheme of things, this is not nearly a bassy presentation, remaining tonally clean and linear relative to most competitors. The note presentation also remains controlled and well-defined, portending towards a presentation that values delicacy over depth and dynamism. However, relative to the stock pads, you do lose a little focus, I noted the stock pads to have a slightly more concise note attack while the Yaxi pads sound slightly smoother and more diffuse. Still, the immediate step up in balance from the stock pads is something I think almost all listeners will appreciate. Of course, this setup still won’t appeal to those wanting a robust, dynamic performance.
By bringing up the bass, mid-bass especially, the midrange sounds more balanced and naturally voiced than before. In addition, I do note a little less lower midrange boxiness on the Yaxi pads, so the presentation becomes wetter and clearer despite a lack of additional upper-midrange presence. Likely, the lower-mid bump was necessary on the stock pads to prevent hollowness in the absence of bass. The Yaxi pads healthily append this and achieve a realistic voicing and timbre in a far more natural manner. The tone assumes a light warmth if retaining good cleanliness overall. Male vocals especially command more gusto and power, achieving better parity with female vocals that tended to steal more focus on the stock pads.
Note body is a smidge more accurate, though the midrange does still sit at the forefront of the presentation. Still, the step up in balance and coherency makes a world of difference. In particular, the timbre and voicing is more natural. While the stock form didn’t sound hollow per say, it was a rather dry and flat sound, with overly smoothed off articulation and diminished warmth. In addition to toning down the lower-mid boxiness, the Yaxi pads introduce a slightly more prominent lower treble which helps greatly to bring the driver’s detail presentation to listener attention. Moreover, it addresses my timbral complaints in the midrange very well, enhancing openness without introducing sibilance. Alongside the bump in body and warmth, the midrange simply sounds more pleasant and correct, more balanced and far less dry and strained.
The treble is affected in equal measure to the bass, yet the changes here are likely the most important. Specifically, I’m hearing a wideband lift across the treble, but mostly, more presence in the lower-treble. This enables the headphone to assume a more detail forward presentation and flaunt its agile transient response. While treble does still sit just behind the midrange, it achieves good balance with the bass and doesn’t overwhelm in the slightest. Control is excellent as is fine detail retrieval. The foreground has good presence and great crispness with the leading edge of each note being highly defined. While body is thin, it isn’t exactly brittle in its note presentation; as with most electrostatic headphones, the timbre is defined more by an ethereal, wispy and delicate character over a bitey and heavily textured one.
There’s a slight upper-harmonic lift that contributes to this impression in addition to drawing small details in the background out a little more. Again, it’s not bright in the slightest nor a headphone heavily focused on air or openness in the treble even with the Yaxi pads. The combo offers a clean and dark background and, while measurements suggest a prominent upper-treble, I’m not hearing a whole lot of air or sparkle above the presence region. Altogether though, bringing more focus to the foreground detail presentation is a very good thing here and it helps to rationalise the burdens of going with an electrostatic headphone system. This isn’t mind blowing TOTL detail retrieval, but surely a well-detailed response for the money and a very different note presentation that enhances this impression and contributes to the whole cool factor of using an entirely radical driver type.
Similar to the rest of the sound, the Yaxi earpads do enhance the soundstage but the changes here aren’t as transformative as above. In particular, width remains similar, stretching just beyond the head but depth is enhanced, granting a slightly more rounded stage. Imaging remains similar too, it was already quick and sharp, but directional cues now come through clearer. The added depth and foreground focus grant a slightly more layered presentation than before too so it does sound more organised on complex tracks. Separation is improved the most, that said, despite the shift towards warmth and coherence. This is so because the midrange no longer dominates the presentation, so details in the bass and treble especially are far easier to pinpoint and appreciate. In addition, separation in the midrange itself is improved due to the reduction in lower-midrange boxiness, so there is more space between each note.
I will be completely transparent here, the Koss ESP/95X is not a headphone I would want to live with day to day. It lacks the versatility of competitors as it is grossly un-balanced. Though clean, this means you don’t really get to enjoy the benefits of its electrostatic design. Along with this, you need to use an electrostatic specific amplifier, the cable is fixed and the build quality is very questionable at best so it’s a lose-lose situation. Introducing the Yaxi earpads into the equation simply transforms the experience in the sense that is makes the ESP/95X a perfectly listenable headphone. You get immediate improvements to feel and comfort in addition to a far more balanced sound. Bass attains has some punch and warmth, so too does the midrange become more accurate and inviting. But perhaps the newfound focus in the lower-treble is the most pertinent change. The increase in overall balance means you get to fully enjoy the speed of the electrostatic drivers without straining to hear details amidst an overpowering midrange. Once again, Yaxi have proven their expertise at designing earpads, catering directly towards deficiencies in the stock frequency response. This makes their earpads a very smart upgrade for current users and something to consider for buyers on the fence about dipping their toes in electrostatic headphones on a budget.
The ESP950/95X earpads are available from Yaxi (International) for $59 USD at the time of writing. I am not affiliated with Yaxi, Drop or Koss and receive no earnings from purchases through this link.