Fit and Comfort

Seen above is the Edifier STAX SPIRIT S3 on a headphone stand that is actually a set of two artificial ears complete with soft-molded human ears and a couple of different adapters acting as the top of the head. This has been mounted on a tripod, which showcases how headphones would look on a human head, with the artificial ears spaced ~20 cm apart. As with all headphones, getting a good fit and seal is crucial, so make sure to properly use the various pivot points, and the height adjustability of the headband and ear cups. This section is mostly a summary of the points expanded upon in more detail on the previous page, but I will point out that the Edifier S3 weighs 329 g—more than the typical set of Bluetooth headphones and this is a result of the planar magnetic drivers no doubt. It also explains the use of plastic for the frame that helps keep the mass down while also being more affordable. We saw before how there are multiple sizing options here courtesy vertical, horizontal, and ear cup swivel movement built in. I had zero issues getting these over my ears comfortable, and I have an average-sized head at that. In fact, there were still some vertical sizing steps left to where I dare say the vast majority of users would be fine with this set when it comes to fit and comfort. I do wish the headband was more plush though, and perhaps something such as the Dekoni Nuggets might be handy here if they can fit in there—or simply add an aftermarket headband cover on top. There's enough clamping pressure to account for a good seal once you have secured the best fit possible, and that helps with noise isolation in either direction while also making sure these closed-back headphones sound as intended.

Audio Performance

Audio and Tech Hardware

The Audeze collaboration comes not only with the design and accessories, but with the drivers too. See, these are planar magnetic drivers that employ a lot of Audeze's own patented technologies. I recommend you go through the relevant section on this page for more on how these drivers work, since it will save a lot of time and space by not having to repeat it again. But in a nutshell, these drivers have dual-sided Audeze Fluxor magnet arrays around a thin diaphragm with magnetic traces that help with uniform and responsive motion back and forth to generate sound that is quite something else if you are only used to dynamic drivers. Audeze's Fazor wave guides also make an appearance here and aim to reduce destructive interference between sound waves as they exit the drivers into your ears. These are similar to what the LCD-1 uses, but where the Edifier STAX SPIRIT S3 differs is in the use of an all-new Edifier EqualMass diaphragm that seems to have an addition trace going around the periphery of the active diaphragm surface for improved response to the magnetic flux and maintaining an ultra-low distortion of 0.5% or lower.


The Bluetooth 5.2 connectivity works flawlessly owing to the Qualcomm Snapdragon SoC, which is likely a QCC50xx unit based on the feature set. I also appreciated that the Edifier STAX SPIRIT S3 supports two-device multi-point support and has fairly good codec support on top. The SoC also helps make this a headset courtesy the integrated MEMS microphone, which works fairly well combined with Qualcomm's cVc tech to allow this to be a respectable two-in-one wireless solution for daily use too. The best part is the whopping 80 hours of battery life provided here, which is a testament also to the efficient planar magnetic drivers and a good justification also for the slightly increased mass here. Now to be fair, this number is likely based on using the SBC codec at ~50% volume, and yet I consistently got 65-70 hours with aptX and ~70% volume before I felt like charging these. This is effectively 2-3x the battery life of contemporary offerings and I took this along for week-long trips without once needing to charge it. There's no ANC here, although passive noise cancellation is more than acceptable with the leather pads while the mesh pads are more breathable and not as isolating. Charging time is also relatively fast at ~1.5 hours owing to the 1.5 A current draw over 5 V DC, and these two things alone push the Edifier STAX SPIRIT S3 right up there in my books. The various controls tied to physical buttons is also a win, and they worked perfectly fine without any frustrations from gestures as with a few other headphones here. Note also that volume control is tied to your source itself, and these got plenty loud even at ~60% volume for me allowing enough range for basically everyone.

Frequency Response Measurement and Listening

I will mention that I have a general preference for a warm-neutral signature emphasizing a slightly elevated bass and smooth treble range with detailed mids and good tonal separation. I also generally prefer instrumental music over vocals, with favored genres including jazz and classical music.


Our current headphones test setup uses a set of two custom in-ear microphones for the two channels. These microphones closely adhere to the IEC711 class, but have been tweaked to be more reliable in the >10 kHz frequency range that was the issue with my previous setup, which is still very good and will continue to be used for IEMs and earphones. Two soft silicone pinnae are installed on the sides, separated by a distance matching my head, and multiple "height" adapters have been 3D-printed for further customization based on fit and head size and shape. Each set of microphones has an XLR output I separately adapted to 3.5 mm. These Bluetooth headphones were first connected wirelessly to my laptop using aptX and Bluetooth, and I used a transparent source, the JDS Labs Element II, for wired listening and measurements.

This artificial head simulator feeds the microphone lines into a reference USB sound card, which in turn goes to the same laptop that has ARTA and REW running. I begin with an impulse measurement to test for signal fidelity, calibrate the sound card and channel output, account for floor noise, and finally test the frequency response of each channel separately. Octave smoothing is at the 1/12th setting, which nets a good balance of detail and noise not being identified as useful data. Also, the default tuning was used for testing, and no external EQ settings were used unless specifically mentioned. Each sample of interest is tested thrice with separate mounts to account for any fit issues, and an average is taken of the three individual measurements for statistical accuracy. The raw data is then compensated based on a custom curve created after having worked with Crinacle from In-Ear Fidelity to get measurements with this setup on par with a GRAS 043AG industry-standard measurement rig, especially by accounting for the slightly different pinna gain here compared to the KEMAR anthropometric pinna there.


As per usual, you can find my headphone frequency response measurements on VSG.squig.link, along with all the earphone measurements. Scroll to the bottom and choose different targets there, including two from Harman Kardon developed after years of R&D. The Harman 2018 over-ear target in particular is a reference curve many headphone makers aim for now, but I find it too bass-boosted. As such, I am opting for the Harman 2018 curve with the bass target from the Harman 2013 curve, which is what is being referred to as the "Harman Combined" target there.

My standards for Bluetooth headphones and earphones are generally low, with perhaps only the MOONDROP Sparks coming to mind when it comes to good tuning out of the box. This is also just my second review of Bluetooth headphones following the final UX3000, but even so I am happy to say the tuning of the Edifier STAX SPIRIT S3 is the best of any Bluetooth headphones I've ever used—reviewed or otherwise. It's not perfect by any means, and please note also that the frequency response measurements with the two sets of ear pads shown above are without any EQ presets or the ear pads selected on the app. Doing the latter at least gets the mesh pad sound signature more in line with the leather pads in the bass and mids, which is a good thing given the bloat we see with the mesh pads in the bass-to-mids transition. Similarly, I will also point out that channel matching was very good here and I simply omitted it here to keep this page to a reasonable length.

There is a definite bass shelf here beginning from 400 Hz and going up ~4 dB with decent bass extension all the way through the sub-bass. This in itself isn't a lot and I can see why people might want to try out the Classic Mode preset in the app which adds an EQ bass shelf by a further 2-3 dB. What makes this stock performance worse though, at least for me, is the bass bleeding over to the mids. I would much rather have seen this 4 dB shelf begin from 200-250 Hz instead, and that would have been a dream set for me and many others. Thankfully this is easily fixed by EQ, but not having any customizable EQ in the app as of the date of this review makes it hard to do. On the plus side, the bass quality is excellent for Bluetooth headphones and plenty good even for wired headphones in the price range this operates in. There is good detail throughout and I definitely got the planar experience with quick decay between notes too.

Some male vocals and bass guitars get muddy owing to the aforementioned bleed, but otherwise I found vocals in general to be prominent and forward-facing over instruments. This is also why I mentioned the set to work well for daily use too, including for movies, podcasts, and communication. Instrument separation is fairly decent too as is imaging, although the soundstage is on the smaller side of average even for closed-back sets so you get a pretty intimate atmosphere that isn't ideal for expansive orchestral recordings. The upper mids actually have a pinna gain, and it is even executed well. In fact, I have very little issues hereon to where I thought the treble frequencies had good presentation and resolution in addition to being well-balanced too. The peak you see past 16 kHz isn't as prominent in person, although I did feel like getting some cymbal harmonics getting in there more so than I was initially ready for. Acoustic jazz in particular played well on these, as did string instruments and even the occasional Kpop/Jpop I end up being subject to. Timbre felt slightly off with drums in particular, even more so than the typical planar magnetic twang, but it's not going to be a prominent feature here to sway your mind one way or the other.


Now is as good a time as any to point out a quirk here—you need to turn on the Edifier STAX SPIRIT S3 even in wired mode! I asked the company about this and was told that the goal is to have a uniform sound experience throughout with people no doubt going to use the set with Bluetooth anyway. This means there's clearly some DSP ongoing here, and it ends up being active for the wired mode too given the sound signature is exactly the same wired or wireless. Imagine seeing your battery drop in wired mode though, although I did note it was lasting longer here compared to the fully wireless mode.


I had mentioned that this is only my second proper review of Bluetooth headphones, so not much in the way of comparisons is to be had. Thankfully, I had a few other Bluetooth headphones on hand, and I quickly listened to and measured some to add in here. The previously reviewed final UX3000 costs a good deal less admittedly, but the other two are either the same cost (but discontinued now) or way more as with the B&O H95. This picture paints far more than a thousand words as it shows succinctly what I meant about the Edifier STAX SPIRIT S3 is easily the best tuned Bluetooth headphones I've used to date. It's also the only one with an actual pinna gain too, which is remarkable to think about given how we take it for granted with wired headphones and IEMs today. The other three have various forms of ANC, and the B&O H95 is also built better with a lot more aluminium to try and justify its premium cost, but I would also give Edifier the edge in terms of the drivers' technical performance and resolving power throughout. Then there's the massive 80 hours battery life + faster charging too, as well as dedicated buttons for everything to where I would easily take this over everything else. The mesh pads help in summer and the various app presets are neat to try out too. That said, the final UX3000 comes real close from a value proposition owing to the lower cost and ANC, so I can't begrudge anyone going that route instead.