Magnets, how do they work?! The Edifier STAX SPIRIT S3 Planar Magnetic headphones review

Introduction

Wen Dong Zhang (CEO, Edifier) was always a fan of STAX, legends in electrostatic headphones, so In 2012 when Edifier acquired STAX, the decision was made to incorporate Planar Magnetic driver tech into a new pair of Edifier headphones.

Enter the Edifier STAX SPIRIT S3, utilising driver technology from Audeze and STAX.

Personally, I have never heard STAX headphones before, but have for a long-time been an avid admirer of the fan-following they have had online and the aesthetic appeal of how they look. I just could not stomach the price tag that they went for.

Specifications

Out of the box

Straight out of the box the first impressions are good. The S3 won't win any records for material quality, it's plastic but is tastefully designed. The plastic feels smooth and in the flesh appears nicer than stock images or photos online might otherwise suggest. After a week I did notice that pivoting the earcups did have some slight creaking which is common with plastic rubbing on plastic. There is no damped/greased articulation here.

The S3 comes with a hard-shell case which is nice to see. Very few headphones come with proper storage in the box, even ones that cost a lot more. The case has an internal pocket, as well as a velour divider, which stops the plastic from rubbing against the earpads potentially scratching the leather pads.

Whilst the earpads are genuine lambskin leather (sorry, no vegan-friendly options here), the headband feels like it is pleather.

The quality of the lambskin pads is pretty good, they are thick and offer good cushioning, although not memory foam, that's where the mesh earpads come in which are memory foam and the outer fabric is a mesh material that feels cool to the touch.

They also look rather premium quality with a unique stitching pattern. They feel much nicer against my head than the leather pads, as well as sounding better to my ears too.

A USB charging cable is included, as well as braided lightweight 3.5mm AUX cable for wired use. A 3.5mm to 6.35mm adapter is included.

The headband does have a fairly tight clamping force, maybe this will loosen over time, but given that these weigh 329 grams, a secure fit is important so they don't move about with quick head movement.

The headband offers 9 notches of adjustment, on my medium-sized head, I found that notch 8 was what offered an optimum fit.

The earpads attach via four points on the back of each pad. These snap into place but to swap out the pads the included removal pick is needed.

The pick looks like a guitar pick, and you simply slide it in between the pad and headphone cup and lever one side out.

You could probably just pull the pads out like on other headphones, but this might stretch out or tear the leather, so best play it safe and use the tool provided.

The showpiece of the S3 is the Planer Magnetic driver which works by moving a diaphragm back and forth using two magnetics on each side. This is different to regular headphones that use a dynamic driver which is being moved by a single magnet.

Edifier claims this is designed to offer extreme accuracy, and in the time that I've been using the S3 so far, I think this claim holds up for as far as closed-back headphones go.

Along with this is a feature Edifier calls Uniforce™, designed to reduce distortion and keep it uniform across the whole diaphragm. As a result of this, the distortion rating is 0.5% which is nearly imperceptible to the ears. What this means outside of technical jargon is that there's little to no chance you will hear distortion on these headphones at any volume.

They also look rather cool compared to regular dynamic drivers, although the only time you will see them is when the earpads are off. It's a shame they are closed back, because a window to see them would have been cool.

Performance

For the bulk of this test, I played a wide range of music from local FLAC to online streaming on my PC which has a cheap Realtek Bluetooth 5.3 USB adapter that I used for the connection to the S3. It is important that I mention something at this stage as it will apply to anyone using Bluetooth headphones on Windows due to the way Windows selects the CODEC it uses for a connected pair of headphones.

Simply put, Windows will not care if your headphones are aptX-HD/LDAC and so on. It will instead select the most baseline CODEC it sees and not bother using the higher modes of it either. This can be checked by using tools like Bluetooth Tweaker (free 7 day trial), which shows what the connected headphones are capable of, as well as what Windows has selected:

In my example above, notice that the S3 shows as supporting aptX-HD, yet Windows is using MPEG-2 AAC-LC, which first came onto the scene around 1997. Using the Alternative A2DP Driver I was able to force Windows 11 to use whatever CODEC I wanted (max supported by any connected headphone), and this solved that problem as can be seen below: This driver also has a 7-day trial, though it is only $7 which I ended up doing anyway, thanks Microsoft....

Not a lot of people are aware of this issue with Windows, even reviewers often fail to mention it as they may not be aware. There is little point in buying headphones to use on your Windows desktop/laptop if you're not leveraging the highest quality it is capable of.

iPhones also are not that much better in this regard, only supporting AAC, although in their defence, the higher modes of AAC are used if supported by the headphones and that's fine, just don't expect aptX-HD/Adaptive/LDAC etc.

Many Android devices do not have this issue, you can enable the highest mode available and watch as it just works in that mode. Note that depending on what brand of headphone you have, you may need to install the brand's app first to enable the higher CODEC mode on the headphone which is then usable in Android, otherwise it defaults to SBC/AAC. Edifier slot sin here as I needed to enable aptX first then it was available, but as I have a Samsung phone, I can only make use of the aptX base CODEC, not aptX-HD.

The S3 also supports Qualcomm Snapdragon Sound, which is a combination of technologies (including aptX) that work together to give the best audio when both ends of the connection support the ecosystem. A limited number of devces from Xiaomi, BOSE, Sennheiser and Edifier and others have this support. A list of supported devices can be viewed on the official page here.

I have a few favourite songs that I go to any time I want to bathe my ears in well-mastered music, many of them are featured in this public Spotify playlist:

However, to break down a few subjective characteristics of my listening experience on the STAX SPIRIT S3, here are a few preferred songs that I found to really highlight the S3's strengths:

Fink - Trouble's What You're In (Live, from 'Wheels Turn Beneath Your Feet')
Each tap of the guitar housing has oomph, vocals perfectly natural and taking centre stage with reverb in surround. The strumming of the higher strings is extremely well detailed without being too piercing or overblown, even at higher volumes.

Allan Taylor - Colour to the moon
Deep vocals immediately apparent with supporting string and wind instruments surrounding you in stereoscopic accuracy. All of them are distinct and natural sounding with no muddying or distortion between any part of the song.

Allan Taylor - Colour to the moon
The go-to for any speaker/headphone fan, and it helps that it’s a great song too. The entire song is superbly mastered with crystal clarity left, right and centre. The S3’s planar magnetic drivers really favour songs like this where everything is so natural sounding.

Lou Berry – Burning Eyes
Imaging is done well on this track, both male and female vocals in the track are recorded with forward and behind the head placement which sounds unique, again the theme continues, every instrument is precisely placed and distinguishable with no loss of clarity of any part of the whole song. Soundstage is wider than what I’ve heard from other closed-back headphones.

Maribou State – Midas
An energetic track with constant bass throughout the whole song. Female vocals are never hidden behind all the bass or other instruments. Vocals are centrally placed with support-vocals coming in with very good imaging.

Crayon – After the Tone
A mellow song but with energetic bass throughout and wide soundstage vocals, the vocals are never muffled by the bass, nor the imaging of the whole track. A good track to listen to on headphones.

GusGus – Crossfade (Maceo Plex Mix)
An absolute banger of a track for testing the bass on a headphone. Not only do these awaken the hidden bass on my HD650s, but the S3 really feels at home playing this song. Bass that you “feel” rather than just hear, and without being boomy or distorted at any volume.

But wait, what about the wired connection?

I tried this out, and quickly went back to wireless as it was just better. I don't know if this is by design, or maybe a dodgy unit, but the wired connection just didn't sound quite right, and there was a low hum electrical interference that I could hear coming from the speakers with the 3.5mm jack connected to my Topping MX3s' headphone jack, almost as if the S3's 3.5mm circuitry wasn't isolated from the power circuit correctly or something.

Your mileage may vary, and even though these are marketed as wireless headphones, I would not expect this sort of issue to exist since passive driving of headphones via wire is an old and fully matured system in itself, it should be impossible to get this bit wrong.

You also cannot use the wired connection passively like regular wired headphones, the S3 must be turned on for wired to work, so battery will be consumed when using them. The electrical noise can also be heard when the headphones are wired in but turned off, like background humming which further bolsters my suspicion that this could be an oversight or a faulty unit.

The funny thing is that I also have the Edifier WH950NB (shown above) which are high resolution wireless headphones that have comprehensive active noise cancellation, LDAC support and proper passive wired mode. I tested these out on the exact same setup and using them wired is possible without having to turn them on, plus, there is no electrical hum.

This confirms one of two things to me, either my unit of the S3 is faulty, or that because the wired connection passes through the same wireless DAC circuitry requiring the headphones to be turned on first which then introduces electrical interference that should otherwise be filtered out. I have reached out to Edifier with my findings to get some clear answers as to why this might be happening and if perhaps a firmware update could resolve the issue.

Doubly funny is that the WH950NB is nowhere near as good sounding as the S3, yet supports all of the higher end features I would have expected the S3 to have such as 3.5mm passthrough, LDAC for lossless wireless transmission and active noise cancellation. The WH950NB is also half the price of the S3.

Having options is always good, even if aptX-HD here offers the best quality, gamers may prefer to use wired mode due to the increase in latency when wireless for gaming. I found no noticeable latency issues watching videos and consuming other media though.

A gaming mode is available which lowers latency, but this is only available through the Edifier app on iOS/Android. This mitigates the effects of latency when gaming. This mode does not seem to save directly onto the headphones meaming there's no way to use it when connected to a device that doesn't have the app available such as a Windows or Mac computer.

The Edifier app

I've touched on the app in this review but now it's time to say a little more about it. On the Google Play Store it has a 2.1 star rating from over 6000 reviews. On the whole I think this is fair. The app does the job, but it is very basic, and its UI seems to change from dark to light depending on what headphones by Edifier are connected, with no way to force a constant dark mode.

I have left the preset in the Classic mode as to my ears this offered the best balance of highs and lows without drifting vocals of imaging away from something that sounded neutral.

The app also handles firmware updates, and whilst the S3 had no updates in my time using them so far, another par of headphones did and it took over 20 minutes to install over the Bluetooth connection.

The app does offer more comprehensive features to other models such as the NeoBuds Pro 2 which I have here. It's just that with the S3, the number of features available are extremely limited s there's only so much available. Even a basic custom EQ would have been nice but you are limited to just the 3 presets shown above, whereas on other models you do have access to an EQ that can be tweaked.

Final words

These aren't the only wireless Planar Magnetic headphones in this price bracket, I need to point out what competition exists so you can decide what might be best for you. If we consider the MSRP, then the Audeze Maxwell wireless gaming headset matches the 80 hours battery life of the Edifier S3 on paper, whilst beating it on other specifications such as having LDAC and LC3 Pro support instead of Qualcomm Snapdragon Sound which is limited to only a handful of devices. The Audeze microphone is studio quality too whereas the mic on the S3 is only just OK, it does the job but is no different to any other mic found on most other Bluetooth headphones.

The upshot is that the S3 can be found in many places far below the MSRP, so this may well factor into a buying decision between otherwise competing headphones.

The STAX SPIRIT S3 is fun, punchy without being boomy, articulate, has good stereo imaging, and the soundstage is wider than what I expected from closed-back headphones. It is my first experience with Planar Magnetic headphones and I am pleased to say it has positively impacted my thoughts on this type of driver for headphones and I look forward to trying out some others in the near future.

They may be quite a bit smaller than full sized open-back headphones like the Sennheiser HD650 above, but the S3 brings music to life in a way I did not initially expect leaving me surprised and impressed. It's given me the itch to try out other Planar Magnetic headphones now, especially an open-backed set. Through this whole review I have tried not to compare them directly against the HD650 as they are very different headphones, they both excel in specific areas and offer a sound that is a unique signature. Each person hears sounds differently too, so my interpretation of this may be different to someone else.

For example, there is a noticeable difference between both headphones when listening to the same song that contains cymbals or a high variation of female vocals where sibilance might be evident. Both headphones tackle these characteristics very differently, neither are better or worse than the other, they are just different, like seasoning your favourite stir-fry, there is no right or wrong really and everyone will have a preference.

There are a few things I don't like about the S3, some of these have been hinted at in this review:

• The weight can lead to some wear fatigue over a long session (~2 hours or more) due to the clamping force of the headband. The memory foam on the non-leather pads does help mitigate this, but not eliminate. These cans weigh 329 grams, over 100 grams heavier than the headphones my head has been used to for the past 20 years!
• Not being able to use them wired as passive headphones may be a dealbreaker for some, especially gamers. With no low latency Bluetooth CODEC support it's a no-go for gaming because the latency is obvious in games even if I switch around what CODEC settings are used in Windows. On a phone it's not so much of an issue.
• My head size is medium if even that, and I found the headband needed to be extended to maximum to provide a snug fit around my head and perfectly centre around my ears. People with bigger heads will likely have contact issues against their ears, especially given that the earcups are smaller than other headphones.
• No active noise cancellation may mean people wishing to use them out and about need to look elsewhere. With the leather pads helps cut out exterior noise passively, but they're not comfortable pads to wear in warmer climates, nor for the best balance in sound quality. The memory foam pad also applies passive noise cancelation, but not enough to mute louder noises outside like traffic.

These are good musical headphones with the score being based on the merits of the Planar Magnetic drivers being so pleasing to listen to. It's a shame that there are some obvious issues that need adressing before I can give it any higher score, and the fact that a lower end model in the Edifier line supports features that the flagship does not. Updates will be added below once Edifier have responded.