With their new Pro iESL Electrostatic Energizer, iFi generously included a pair of King Sound's KS-H3 Earspeakers. They have been my first exposure to electrostatic headphones, and I've very much enjoyed my time with them. The transient response and general quickness with which they create sound is unique, and absolutely wonderful to hear.
Fit and Form
The KS-H3 came to me in a very convenient, and surprisingly small, fabric-clad, hard-shelled, zippered case. They fold completely flat for storage, and their 5-pin Pro Bias cable wraps up nicely. Although wide, the cable hangs nicely and isn't too microphonic. Although movement is audible without music playing, I wasn't disturbed by it once I hit "play". The cables are permanently attached at each ear-cup, but I don't see that as a longevity issue, as these really aren't "on-the-go" headphones.
I'm a fan of the design of these headphones, but it's rare that I'm offended by design, so that may be a moot point. The mainly black ear-cups have a chamfered edge in a bronze coloration; I believe both the black and bronze are either anodized or (more likely) PVD coated. The headphones rotate 90 degrees (flat) at the hinge, and two arcs of spring steel wrap high over the head, while a leather-clad strap sits underneath that, responding to the pressure of the top of the head to automatically adjust to the user's head size. These headphones are fairly light, so this wasn't an issue for me, although I could imagine that if someone has ears that sit very low on their head, these might not drop enough to reach them comfortably.
The ear-pads are a bit shallow, although they are made of a nice quality, if thin, leather. They are completely circular, and cover the flat grill which covers the electrostatic diaphragm. I did have an occasional issue where my helix would uncomfortably rest against this covering, but that only came out in very extended uses, over 3 hours usually. Additionally, I've found that I have pretty sensitive ears to discomfort in headphones, so your mileage may vary, if you are in the market for these headphones.
But comfort and design, that's not why you buy these headphones. You buy them for the sound. And that's what I'm about to get to but (spoilers), it's pretty incredible.
There's a reason that there is this overarching mythos that surrounds electrostatic headphones. Incredible clarity, unrivaled transient response, with absurdly low distortion and tremendous dynamic sensitivity. That's a whole lot of buzz words, and I recognize that; they were chosen very purposefully. These headphones live up to that hype, and surpass it in many ways, some that I didn't expect.
Having read much media about electrostatic headphones in general, and some about these in particular, I came in with some expectations that were met and some that were surpassed. I expected all of the above buzzwords - how could I not? Those are what reviewers tend to offer as the defining characteristics of this section of the market. However, there were other things that I expected. I expected thin, anemic bass, without much ability to satisfy my occasional bass-head cravings. I was wrong there. I expected a cloistered, congested soundstage, with great imaging and separation, but not much more than that. Wrong there too.
These are the things I want to get through over the course of this review, because I feel that these offer an extremely good bridge between the benefits of dynamic and planar drivers, and electrostatic drivers.
So let's get to it then. Sub-bass takes a hit in a big way, losing a lot of impact, but still maintaining some good rumble. I was surprised as the amount and quality of mid-bass, with there being good potential for some punchiness and great texture where called upon. The mids are absolutely the high point. Natural and detailed, with just the right sense for lushness without airing on the side of inaccuracy or soupiness. The highs reach very high, creating a tremendous sense of airiness and space in the sound signature.
The soundstage isn't massive, I'll admit that, but it isn't the two-dimensional stereo image that I expected when I walked into these headphones. Imaging and separation are as great as I would expect them to be, with each instrument and vocal line coming through as exactly distinct, while somehow simultaneously creating a cohesive, ensconcing mix of sound that just embodies musicality.
Songs used: Three Ralphs by DJ Shadow, Black Eunuch by Algiers, and Feels feat. Pharrell Williams, Katy Perry, & Big Sean by Calvin Harris
Here was the first surprise I encountered with these headphones. Sure, sub-bass is massively reduced, but mid-bass has pretty good presence. More than just presence, the texture and detail, beyond just impact, was impressive, and very amicable. Bass guitars, with any combination of pedals, come through with great fidelity, straight down to the sound of the pick striking the metal string. Electronic synthesizers fare exactly as well, with a very tactile and realistic feel, almost as if you could reach out and grab the instrumentalist by the hand. All this isn't to say that these are bass kings or that this range is the emphasis, as it certainly lies below the mids, but it is much more present than I expected it to be, and in much better quality. They do not compare to a great pair of dynamics, per se, but I just wanted to emphasize that the sound signature isn't empty or hollow, by any means. They lose a little bit of weight behind some impacts, but beyond that, they are very competent performers.
Key descriptors: recessed, detailed, and tactile
Songs used: Scarlet Town by Chris Thile & Brad Mehldau, Cajon by Daniel Waples & Friends, and Mama's Gun by Glass Animals
The mids are the high point of this set of headphones, without a single doubt in my mind. The incredibly fast response of the electrostatic driver allows a tremendous sense of realism to this frequency range. I wouldn't go so far as to call it lush, per se, but it leans to that side, compared to thin, edgy, or anemic. Vocals particularly, of both genders, come through as though the singer is right in the room with you. The delicacy and caution that the speed of these drivers allow means that every single breath, every intake of air between notes is caught and conveyed nigh-perfectly. The same is true of instruments, with the strokes of guitars and mandolins being so realistic that when I close my eyes, I swear I could see Chris Thile plucking away. There is, to my ears, a slight peak in the upper mids that can make the upper-end of the piano's spectrum a little bit sharp, but with some tasteful volume control, I avoided that issue pretty easily. To give a more specific note to the detail that I found in these headphones, I actually noticed what I believe to be a production quirk in the track "Mama's Gun" from Glass Animal's sophomore album, How to Be a Human Being. Right in the beginning, in the right channel, there is a slight crinkling that was reproducible consistently enough for me to be sure that it is not just the headphones diaphragm responding oddly. It's extremely low in volume, but I had never heard it before, and appreciated that these were revealing more of a track to me than I had heard before.
Key descriptors: detailed, articulate, and realistic
Songs used: Down the Road by C2C, Ageispolis by Aphex Twin, and Goodnight Kiss by Ibrahim Maalouf
The treble is another high point of these headphones, and it supports the mids in much the same way that the treble in Venture Electronic's Monk+ earbuds did. It adds a great sense of air and space to all the music that I put through these. It extends very high without much apparent effort, and I didn't notice much peakiness to speak of. I encountered no sibilance whatsoever in my use, thankfully, and didn't come across any other unpleasantness of which to speak here. Overtones are presented with the right emphasis, such that timbres of individual instruments are not bastardized, which similarly helps the realism and naturalness that I referenced earlier. I oftentimes find myself, as a drummer, harping on the presentation of cymbals by many lower-end headphones, as they blur the attack and decay too much to seem truly realistic, but these did a great job there too.
Key descriptors: extended, airy, and detailed
Minutia and Miscellaneous
The leather on the ear-pads does seem like a longevity issue to me. I am aware that I got a used pair, so I do not fault King Sound directly for this, but the leather on my ear-pads was noticeably flaking, which could either be from lack of proper care on the original owner's part, or from overuse over time. Just something to note, though that should be taken with a grain of salt, as I can't account for where the theoretical fault lies. However, they are user replaceable, so at the very least, it is not a permanent issue.
If you can't tell by the content of this review, I very much enjoyed my time with these headphones. They are a true embodiment of the incredibly nebulous moniker "high fidelity" and I feel that they represent a great entry point into the world of electrostatic earspeakers. They are not alienating in the slightest, retaining a good share of mid-bass while adding the tremendous transient response, dynamic sensitivity, and all the other buzz-phrases that surround electrostats. These definitely fall on the list of the most musically pleasing headphones I've heard, as they are satisfying both in a casual listen, and in a deeply analytical listening session. Highly recommended if you have the cash and the equipment necessary to do these headphones justice.
These headphones were provided to me for review by iFi Audio. I am not being paid by anyone to write this review, to endorse the product reviewed, or for the content that I put in the review.
These headphones were powered by an iFi Pro iESL, which was fed signal from an iFi Pro iCan, which was fed signal by USB from my computer.
I have had these headphones for about three weeks, and I have put about 50 hours of analytical listening through them during that period.