HED Unity Full Fidelity Wi-Fi Headphones Review
Simon Lucas auditions this premium-priced pair of high-end, Wi-Fi-enabled headphones…
Unity Wi-Fi Headphones
AUD $3,525 RRP
Ever since Bluetooth came of age and wireless headphones began to dominate the market, sound quality – or the lack thereof – has been the stick of choice with which to beat the technology. Advances by Qualcomm (with its various aptX codecs), Savitech (with LHDC) and Sony (LDAC) have allowed wireless streaming via Bluetooth at higher resolutions. However, lossless is the Holy audiophile Grail, and none of these codecs can truthfully claim to allow lossless transfer of data.
Wi-Fi, then, would seem to be the way forward if ultimate sound quality from wireless headphones is your aim. The impediments, especially in terms of efficiently implementing the required technologies and being able to maintain some semblance of workable battery life, have always been considerable.
Until now, that is. Swiss company HED Technologies, a brand with next-to-no profile, has delivered what it's pleased to announce as “the world's first wireless high-definition lossless audio headset”. It is called Unity and has one of those price tags that strongly suggest it's a world first. But as we all know, charging a premium price is not automatically the same thing as selling a premium product…
Adding perceived value to some product types is far simpler than it is to others. Over-ear headphones, to take an example not entirely at random, are tricky. Form follows function very closely here, and unless you decide to cover your headphones in Swarovski crystals or suchlike, one pair is going to look very much like another.
To be fair to the HED, however, it has done what it can to make the Unity seem like an upmarket proposition. The earcups are milled from a single billet of 6063 architectural-grade aluminium and feel just as good as they look. The frame of the headphones is carbon fibre-reinforced nylon, which contributes strength, light weight (the phones weigh in at a trim 421g) and vibration rejection. The headband is of strong-yet-flexible polyamide. The earpads are of memory foam combined with cooling gel and are covered in a soft microfibre material. The overall aesthetic is clean and understated, branding is minimal, and the carefully considered and smooth-sliding hanger arrangement means even the narrower-headed among us won't find all that much of a gap between the sides of their head and the Unity headband.
As far as specification is concerned, HED Technologies has had an equally spirited go at making these headphones seem like they might be worth the asking price. The 40mm titanium-coated full-range dynamic drivers deliver a claimed frequency response of 20Hz to 20kHz. Battery life from a single charge is between six and eight hours, depending on how you're using the headphones and at what sort of volume. Recharging from flat takes around ninety minutes, while five minutes or so on the juice should hold you for an hour's listening. Charging takes place via the USB-C input on the left earcup – this is also used for data transfer, by the way.
The Unity's complex and unusual SkyDex carry-case contains a USB-A to USB-C cable, a USB-A to USA-C adapter, and a USB-C to 3.5mm adapter – so wired, passive listening is easily achievable. The Unity can be wirelessly connected to your source of music using Bluetooth 4.2 – there's compatibility with the plain-vanilla SBC and AAC codecs. But that's really not the point of the wireless performance that's available here. HED Tech describes the phones' ability to wirelessly stream from music streaming services or local storage using Wi-Fi as 'Full Fidelity'. And there's no denying that the ability to stream losslessly at resolutions of up to 24-bit/96kHz is probably worth a bit of marketing hyperbole.
Access to the big hi-res audio content you'd like to stream comes via the Unity control app, that's free for iOS and Android. It incorporates what HED likes to call a 'Multisource Music Player'. Give it access to your local media files, any DLNA or UPnP devices, integrate your Soundcloud or Qobuz accounts, and you've centralised access to a whole stack of audio content. Spotify Connect and Apple Music are supported via their own apps, and the likes of TIDAL, Amazon Music and Deezer currently aren't supported at all. Apparently, TIDAL Connect will appear sooner rather than later, courtesy of an app update. It also offers nine-band EQ adjustment, an indication of remaining battery life, confirmation of Wi-Fi connection, and a toggle to switch active noise-cancellation on or off.
There are basic playback controls in the app, too. Further control is available using the four buttons arranged around the edge of the right earcup – the classic three-button strip takes care of playback and volume control, while the fourth button can have its function defined in the app.
There are a total of twelve mics, eight digital and four analogue, distributed across the chassis of the Unity – and they take care of active noise cancellation and telephony. You might think that an outlay of this magnitude would buy you some touch controls or the ability to engage with a voice assistant, but you would be wrong. However, it does seem that a native HED Unity voice assistant is coming in early 2024, but for now, you'll be wasting your breath.
What you do get is a complex 'inertial measurement unit' consisting of a three-axis gyroscope, three-axis accelerometer and three-axis compass. This means the design has a nine-axis set-up for head-tracking and motion detection, which is handy for Audio AR and the like.
Hearing the Unity is not a difficult thing to do, but achieving any kind of consistency when it comes to the content you're listening to is harder than it should be right now. The problem is the Unity control app, which seems unfinished. It is often unable to synchronise the information it is displaying with the content it's actually playing, and it has an almost avant-garde approach to time-keeping thanks to its tendency to revert to the beginning of a playlist should you be negligent enough to let your smartphone's screen (if that's what you're using as an interface) go to sleep. It's called 'beta testing' for a reason, guys and paying customers should never be involved – especially when they're paying as much as this.
These headphones are capable of insightful, exciting and convincing sound quality. Whether it bears comparison with similarly priced wired headphones attached to an equally capable source player is debatable, but that's beside the point. By the standards of wireless headphones, the Unity is among the very best.
Even a bog-standard 16bit/44.1kHz file of Such Great Heights by The Postal Service impresses across the board. Detail levels are sky-high; whether it's the analogue grind and squelch of the keyboard-derived bass or the deliberate tinniness and edginess of the percussion, the Unity communicates the finest details with relish. When the second vocal line starts to harmonise with the main melody, it's possible to discern the gate on the mic opening. There's no doubt that these headphones are serving up the complete, unexpurgated picture.
The party piece is, of course, the ability to deal with full-fat 24-bit/96kHz digital audio files losslessly – and when given a Qobuz-derived file of Kris Kristofferson's Jesus Was a Capricorn to deal with, the sound is thrilling. Tonality is life-like and convincing, and detail levels are remarkably high. For example, it's possible to identify the guitar strings themselves and the device being used to pluck or strum them. Low-frequency sounds are deep and textured and are controlled with absolute certainty; rhythmic expression is confident as a result, and momentum is naturalistic. The opposite end of the frequency range splashes or bites as required, and the substance given to treble sounds balances out their brightness in a beautifully judged fashion. In between, the vocal has immediacy and character, while the supporting harmonies at the back and the sides of the stage are every bit as persuasive.
There's a large, three-dimensional soundstage with just as much 'front/back' distance available as 'left/right'. It opens up even a complex and instrument-heavy recording like Talk Talk's Desire with assurance, marshalling each element into a position where it enjoys sufficient space to express even the most subtle nuances of its performance. At the same time, it manages to integrate each strand of the recording into a unified and plausible whole.
Where dynamic potency is concerned, this design is equally accomplished. The distance these headphones can put between the quieter, more contemplative moments of the Talk Talk recording and its guns-blazing climaxes is considerable. Also, the harmonic variations it can tease out and contextualise during those moments of near-silence is remarkable, too.
Given this list of sonic accomplishments, it's perhaps most extraordinary of all that the Unity's overall presentation is in no way showy, fussy or overblown. Instead, a winning balance is struck between entertainment and information overload that allows the character of a recording as much expression as possible. No matter if it's musicianly, expensively produced and high-gloss, or cheap, ramshackle and hurried, you get what's on the recording.
This is the best-sounding wireless headphone design that I have heard to date, but would I buy a pair? Well, that all depends. Even if the Unity was operationally perfect, it's fearsomely expensive – so a long, hard think would be required. And the ergonomic shortcomings start off as irritating and end up as enraging; by the end of the testing period, I was almost taking its various flaws personally. So no, I'll pass thanks – which is a weird thing to say about the best-sounding wireless headphones out there to date.
Simon was editor of What Hi-Fi? magazine and website and has since written for Wired, Metro, the Guardian and Stuff, among many others. Should he find himself with a spare moment, Simon likes publishing and then quickly deleting tweets about the state of the nation (in general), the state of Aston Villa (in particular) and the state of his partner’s cat.
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