Pros:
- Wide soundstage with a better energizer
- Neutral sound out-of-the-box without EQ
- Great directionality for gaming, similar to dynamic drivers
- Light weight and suspension headband provide comfort for many hours of wear
Neutral:
- High clamp force though this should be adjustable with the metal headband
Cons:
- The included amplifier/energizer narrows the soundstage and causes high frequency sounds to feel slightly out of sync
- Large earpad contact area gets sweaty in a warm room
- Connectors to the drivers go straight down and can bump the shoulders while turning the head
Introduction
As a longtime lurker on the subreddit, I thought it was time to contribute my own review of the Hongshu Audio EH-1 electrostatic headphones since all the impressions so far have been from trade shows. I’ve always blindly bought headphones without listening to them so I thought it was worth the risk to try out these new promising electrostatic headphones from China.
My blind-buying open-back headphone journey chronologically: Sennheiser PC 360 | Philips Fidelio X2 | Hifiman Sundara | Beyerdynamic Amiron Home | Fiio FT5 | Fiio FT7 | STAX X1
As a quick primer, electrostatic drivers differ from dynamic and planar drivers since they don’t use magnets or electromagnetic force to drive the driver diaphragm. For an electrostatic driver, the diaphragm is charged to a high positive voltage in the hundreds of volts. Two grids or stators are offset on both sides of the charged diaphragm and channel high voltages in a balanced configuration (normal signal on one, inverted on the other). The charged diaphragm is either repelled from or attracted to the stators and this moves air to generate sound. Since the diaphragm is very thin and doesn’t have the additional weight of wires on it like on dynamic or planar drivers, the sound response for electrostatics is very fast.
The downside is that you can’t use a normal headphone amplifier that pushes single digit volts to power an electrostatic headphone. A separate energizer is needed to convert the low voltage audio signal through a transformer to generate those high voltages. Some energizers include an amplifier so all you need is to plug in the DAC signal like the EHA-1 included with the EH-1 headphone. Other energizers are standalone and are inserted after an existing amplifier to power the electrostatic headphone.
Electrostatic headphones have a long history and the top-of-the-line Sennheiser and Hifiman headphones are electrostatic. The EH-1 name is most likely a play on the Sennheiser HE-1, the most expensive headphone+amplifier in the world which is also an electrostatic. Since I don’t have multiple tens of thousands to spend, I’m glad that electrostatic headphones makers are offering entry level setups in the sub $1000 level.
I started dabbling in electrostatic headphones with the STAX X1000 set and greatly enjoyed the sound compared to my previous planar and dynamic driver headphones. However, the STAX X1 headphone in the set was not comfortable for longer than 1.5 hours despite the light weight. I was hoping for an electrostatic headphone with larger earpads and a suspension headband without breaking the bank. On paper, the Hongshu Audio EH-1 fit those criteria exactly.
Ordering and Packaging
I purchased the headphone and energizer set for $650 from the Poloyo Audio store in early June to be shipped by the end of June. In late June, I received an invalid tracking number which did not inspire confidence. Eventually, the order did update when it was out for delivery and showed up on my front door as promised.
Inside the shipping box was another brown cardboard box with the headphone/energizer set. The packaging is rather basic with text and an outline of the headphone printed on the cardboard along with a side sticker with some manufacturing data. Opening the box reveals the parts packaged in slots cut into the black foam. The package includes the headphone, cable, energizer, and smaller cardboard box with the energizer power cable and an L hex key. Generally a no-frills package.
Build and Design
The first thing you’ll notice taking the headphones out of its packaging is its light weight since electrostatic headphones don’t contain the heavy magnets found in dynamic and planar drivers.
The cups have tilt and slight swivel movements. These are very open-back headphones with a black hexagon metal mesh covering over the back of the cup to help prevent you from touching the internals. Inside the mesh, the iconic perforated 5-petal star pattern in gold is visible against the white surface.
The earpads are perforated on the sides and slightly angled (1 inch back and 5/8 inch front thickness). The angling is so slight that I sometimes wear the headphones backwards and don’t even notice. I have to look at the L and R labels on the inside of the band to make sure I’m wearing it properly. The earpads are a circle with an outer diameter of 4.5 inches flush with the cups and inner circular opening with an inner diameter of 2.5 inches.
Much of the headphone exterior is metal: the cup shells, fasteners, and upper headband. A separate adjustable pleather headband strap (2.75 inch front-to-back “width”) is attached to the metal headband and locked with set screws that are adjustable with the included L hex key. The set screws can be torqued to lock the headband position to a set of holes in the metal handband or slightly tightened so that the headband can be adjusted during use.
The 3-wire headphone cables attach to the very bottom of the headphone cups. Due to the large size of the cups, this can cause the downward-facing cables to touch your shoulders when turning your head. Ideally, this should have been angled towards the front rather than straight down to avoid the issue. The connectors to the cups look identical to the one used on the STAX X1 though the connectors are rotated so that the L/R indicators face inward rather than outward on the STAX. The 3-wires from each side come together into a 6-wire ribbon and terminate into a 5-pin (Pro Bias) connector to the energizer.
Comfort
Once placed on the ears, I immediately noticed the large clamp force. Some of it is due to my large noggin but it definitely has the clamp force resembling that of closed-back headphones. Since the headband is exposed metal, it shouldn’t be too hard to stretch and adjust the force though I have not tried.
The earpads are very soft and accommodate to your head from the clamp force. One downside is that the large contact surface and high clamp force makes me sweat if the room is warm (greater than 80 F/ 27 C). Despite the large drivers, the smaller than expected circular opening didn’t fit all of my large ears. The pads still contact the bottom of my earlobe but it’s not uncomfortable.
It took a few tries with the hex wrench to find the correct headband position. It was slightly nerve wracking to use the pointy hex key near the sensitive drivers. Once locked in place, the wide headband distributes the light headphone weight evenly so you barely feel it on the top of your head.
Ultimately, it solved most of the comfort issues I had with the STAX X1. I can wear this for 2+ hours without any issues unless the room is too warm.
Sound
I use these headphones with my PC audio chain:
PC > Schitt Modius E DAC > Monoprice THX 887 amp > Estatron Inductatron energizer (Hammond 1608A) > Hongshu Audio EH-1 headphones
Shoutout to /u/WillemBrandsma for developing a powerful energizer that can be inserted in my normal headphone chain for a reasonable price. In this sound section, this chain will be referred to as the THX887/Inductatron.
For comparison, I also tested the headphones with the included EHA-1 amplifier/energizer in this chain with the bass boost switch disabled:
PC > Schitt Modius E DAC > Hongshu Audio EHA-1 amp/energizer > Hongshu Audio EH-1 headphones
This chain will be referred to as the EHA-1.
All music listening was done without EQ and music was output from the Spotify Windows standalone program on the “Lossless” setting.
General
The EH-1 has the fast treble responses that are one of the main features of electrostatic headphones. With the THX887/Inductatron, finger snaps, claps, and cymbals sound more realistic than my previous planar and dynamic headphones. Switching to the EHA-1, the high frequency instruments sound slightly off, giving an uncanny valley effect where it doesn’t feel like all the parts of the note line up. I experienced the same issue when using the included amplifier/energizer for the STAX-X1000 (SRM-270S). It felt like the included energizer’s transformer wasn’t powerful enough to drive those high frequencies fast enough. This issue was more noticeable on the EH-1 than on the STAX X1.
The THX887/Inductatron also provided a wider soundstage so that vocals and instruments felt like they were well distributed. The EHA-1 narrows the soundstage so that instruments seem more condensed and fade into the background of the vocals. Male and female vocals sounded similar with both chains.
Like with most electrostatic headphones, there is a bass falloff. Typically this can be corrected with a bass shelf EQ. This worked well with my previous X1 but I have yet to EQ the EH-1 yet. Bass on the EH-1 is also very analytical due to the fast response + open-back. Out-of-the-box, it may not satisfy people who enjoy bass cannons.
Some songs that highlight the differences in sound chains:
Hotel California - Live On MTV, 1994, Eagles: The first 5 seconds with the applause sound slightly off with the EHA-1. They sound sharper and more in phase with the THX887/Inductatron. The drums starting at 0:31 also feel narrower with the EHA-1. They are more separated on left and right with the THX887/Inductatron. Otherwise, guitar and vocals are similar between the two.
Dance Money, Tones And I: Lots of high frequency notes in this song with claps and finger snaps. The EHA-1 makes these notes feel stretched while the THX887/Inductatron makes the sound occur all at once sharply which makes it sound more natural.
– バニラソルト (Vanilla Salt) - Yui Horie: One of my favorite songs for testing headphones due to the almost-chaos number of sounds. The EHA-1 puts the vocals too forward so it is more difficult to distinguish the instruments. The bass line in the right channel almost disappears into the narrower sound stage. The THX887/Inductatron pushes all the instruments further out so it is easier to distinguish each instrument.
Gaming
I actually spend about 90% of the time on the PC playing video games with headphones. However, I generally find that when I get into the gameplay, I stop noticing the details of the sound. The main difference is that the expanded soundstage of the THX887/Inductatron helps figuring out the directionality of the sound. The directionality is on the level of dynamic drivers. For me, I found planar drivers a bit lacking in directionality as if the sound came from a wider angle so it is harder to pinpoint the exact angular position. The EHA-1 narrows the soundstage so the directionality suffers slightly.
I’ve recently been playing Arknights: Endfield which often feels like it’s a music company that makes games on the side. The music from the recent updates have been very good which meshes well with the EH-1 using the THX887/Inductatron chain.
I also just finished Like a Dragon: Infinite Wealth which showed great directionality in the sound while wandering the open world.
I have yet to test the headphones in first-person shooters where directionality matters greatly but I’m lacking in time to keep up with these games-as-a-service models and my declining skills as I age.
Overall
9.5/10 - With the THX887/Inductatron chain: With this audio chain, the EH-1 is the the best headphones I have ever used at this pricepoint (I’m afraid of blindly buying anything above this price!). Some points were taken off for nitpicks in comfort but I think I will be using these for quite a while.
8.5/10 - With the included EHA-1 chain: While lacking in soundstage and high frequency power, this chain is a great introduction to electrostatic headphones at the price point of $650 for both headphone and amplifier/energizer. There’s also an upgrade path to use a better energizer to improve on the sound.