Wing Acoustics Zerø Standmount Loudspeakers Review
David Price samples a radical and exciting new New Zealand-designed and built miniature monitor…
Zerø Standmount Loudspeakers
Spoiler alert. I've been reviewing loudspeakers since 1993, and the Wing Acoustics Zerø is one of the most technologically interesting designs I've come across. Despite it costing just £3,660 (USD $5,000; AUD $6,550), in its own specialised way, this is one of the finest sounding small speakers I've heard. Yet there's also a huge, ocean-going caveat because it's simply not suitable for most speaker buyers' requirements.
Let's get this straight from the start, shall we? This tiny speaker is designed for near-field monitoring. Like the classic BBC LS3/5a before it, it simply is not purposed for driving large rooms to high levels. Instead, it's designed for small spaces and critical listening at low to medium sound pressure levels. Put crudely, if it's a banging house party you're after, then stop reading this review now and buy a pair of JBL L100 Classics.
The Zerø sports a new type of transducer to handle the treble and midband, which the manufacturer calls acousticWing. It touts this as, “the most significant breakthrough in loudspeaker development since the invention of the cone one hundred years ago”, no less. It's certainly a fascinating and novel design with excellent transient speed and low distortion. Yet its particular characteristics are such that, when allied to its petite cabinet enclosure with an internal volume of just 2.6 litres – yes, you read that right – this speaker is unduly hard to drive, and doesn't go very loud.
I wouldn't normally obsess over tech specs, but they're important in this context. Wing Acoustics claims a sensitivity of just 72dB (2.83V, 1m). This is so much lower than conventional loudspeakers that it's actually quite limiting. My experience of various versions of the BBC LS3/5a and its numerous imitators, for example, is that they clock in around 80dB to 82dB. This is already very low – an average small speaker like the classic Wharfedale Diamond is around 86dB – so 72dB is practically off the scale.
Then there's the low quoted nominal impedance of 4 ohms, which the manufacturer says drops down in places to 3.2 ohms, for added amplifier matching fun and games. These two points mean that you'll need an amp of serious power and load-lugging ability. The company doesn't dance around this, to its credit, describing it thus: “Extremely power hungry. Many amps simply do not have enough headroom to drive this speaker, so it requires careful amp selection.”
In fairness, in 2021 that's not as big an ask as it used to be – there are lots of gutsy, punchy power amps around these days at surprisingly affordable prices. Yet still many people won't already own one; my various reference systems are centred around lower power amps driving higher efficiency speakers, for example.
So I had to reach deep into my amplifier cupboard to find something to suit and settled on my recently restored NAD 3155/2155 integrated/power amp combo. In bridged mode, it puts out a claimed 300W RMS per channel into 4 ohms, and can handle 2-ohm loads – so was ideally suited. I also tried several other amplifiers I had to hand, ranging from an Electrocompaniet AW250 with a quoted power of 2x380W RMS per channel into 4 ohms, along with my 18W RMS per channel World Audio Design K5881 valve power amp, from the 4-ohm tap. The latter didn't mind the load one bit and sounded very nice, but didn't go very loud!
The Zerø's low efficiency and impedance mean that it's a no-no for many hi-fi amplifiers then, but by no means all. I got respectable volume levels in my largish listening room in practice, but it's no party animal. Wing Acoustics clearly states it is purposed for near-field and/or small room, and anything else is a bonus. It's very small – “no taller than a wine glass”, as the manufacturer puts it – measuring just 225x165x225mm, but far heavier than you might think at 7.7kg apiece. This makes the speaker sit in a stable way in a small space, on a bookshelf, desk or chest of drawers – whatever. For me, this is so much of its charm – being so small it's hugely accessible and is designed to deliver high sound quality is places that normal speakers just can't reach. I can imagine it sitting in home offices the world over, playing music streamed from a Chord Hugo/2go DAC/streamer and a compact Class D amplifier, for example.
Okay, so what's the big deal about this new drive unit then? The company describes it as an ultra-rigid wing that moves in a precise arc: “It mimics the action of a hummingbird wing in flight”. It's clever stuff which – despite its completely different mode of operation – reminds me of NXT technology because when it arrived, it was completely unlike anything else around.
The concept was born in 1998 by Kiwi audio engineers Mike and David Palmer – both of whom are also classical musicians, and work began on the speaker in January 2019. They claim that this new transducer has “zero detectable resonance distortion over the widest operating bandwidth ever achieved: 80Hz to 20,000Hz”, no less. Also, it has better time-domain performance than standard moving coil drive units because it avoids many of the aforementioned's problems – unstable pistonic action due to the cone profile and material, and the working of the rubber cone surround.
Wing Acoustics' Chief Executive Christopher Hardy told me that, “the Wing is the only diaphragm that is a self-supporting three-dimensional structure which – as well as being ultra-lightweight – is rigid across almost the entire operating bandwidth. For example, the first (very subtle) diaphragm resonance mode occurs at 17kHz, which is at or beyond the upper limit of the audible bandwidth for most people. This means that “whereas conventional diaphragms undergo their own characteristic and audible flexing vibration, it is impossible for the Zero's Wing diaphragm to do anything other than faithfully reproduce audio, regardless of the complexity.”
That's quite a claim. He continues, “because the Wing driver has no floppy rubber diaphragm surround or other flexible zone, it is possible to achieve high diaphragm excursion and improved low-frequency extension, without making the surround more floppy and thereby worsening high frequency muddiness. In this speaker, the low frequency extension of the Wing driver lets us employ an unusually low crossover frequency of 570Hz, which leads to purer midband reproduction. The absence of a diaphragm surround does mean that we have to ensure that air doesn't escape past the diaphragm, which we do by keeping the air gap at the diaphragm periphery sufficiently narrow.”
It's fascinating stuff then, but something we don't have time to further explore in this review - more information can be found on the company's website. Suffice to say that it's already the subject of over two hundred international patents, so I suspect it will be discussed at length in years to come.
The Zerø loudspeaker itself is more than just the acousticWing mid-treble driver, of course – there's also a 75mm woofer that kicks in below 570Hz and a 100mm passive radiator. Wing Acoustics claims a frequency response of 35Hz to 20kHz, saying the bass cut-off point is -6dB. That's very low for a speaker of such diminutive dimensions, forcing me to wonder if the designers would have been better served dialling in a little more sensitivity in exchange for a little less bass extension? Frankly, I question how many people put low-end bass extension before sensitivity.
The cabinet is a thing of beauty – and for any other loudspeaker would be a huge talking point. Constructed from anodised aluminium, its outer walls are 7mm thick extrusions and the front and rear baffles are 1kg each of cast aluminium. The result is a very 'dead' enclosure that has a sort of 'ruggedised' military feel to it. The Zerø has the look and presence of something exotic, unusual and designed to do a specific job of work – which is exactly the case. There are no gimmicks, no fancy finish options or fussy styling details, which I found highly endearing. Rather than having the feel of swanky high-end hi-fi, it feels like a piece of pukka pro gear, something that's built to last regardless of what's thrown at it. I also suspect that its functional, 'anti-style' aesthetics will age better than most.
The cabinet walls are doubled up; there's an inner enclosure, housing the acousticWing driver, that is contained within an outer aluminium enclosure. The former is described as “an anechoic chamber employing wedge-shaped foam to absorb sound waves across a wide bandwidth thereby mitigating unwanted internal air resonance.” The Wing driver is decoupled from the inner enclosure, and the inner enclosure is decoupled from the outer enclosure. These systems interrupt the pathway by which mechanical vibration originating at the Wing driver might otherwise reach the outer enclosure, and thereby reach the listener. Both are braced and damped, and constrained elastomer damping layers are located between the bracing and the wall, and around the perimeter and mounting fastenings of the front panel.
For a speaker with such unusual measured performance figures, in practice, the Zerø proved more user friendly than I'd expected. Indeed in terms of placement, it was a dream, working well wherever I located it. I didn't ram its dinky enclosure too hard up against the boundary wall of my listening room but still kept it fairly close at about 15cm out. This gave a subtle amount of bass reinforcement, without the low end becoming overblown. The Wing also worked much better off-axis than most speakers, meaning you don't have to be sitting right between it to get in the sweet spot. This fact alone makes it much easier to live with than conventional designs.
Suitably positioned and matched to an amplifier that can drive it properly, the wee Wing has star quality. Put simply, it doesn't sound too dissimilar to a classic Quad electrostatic that's been distilled down to its pure essence. Those same magical qualities are there; a delicacy and subtlety that's hard to find in a conventional box speaker with moving coil drivers, plus a tonal evenness and consistency across the midband – where it counts – and great transient speed. The result is a svelte, sophisticated sound that's also fast and musically communicative. Many speakers I've heard have some of those qualities, but few possess all of them.
Just because it sounds like a baby electrostatic doesn't mean you have to feed it suitably sophisticated programme material. For example, Toto's Hold the Line – a catchy but overblown bit of late seventies pomp – was a blast. This came down to several factors – firstly the Zerø was able to tell me all about the production of the track. Here we have, it disclosed a clean and dry rock recording that was heavily compressed for nineteen-seventies FM radio, with a searing electric guitar centrepiece, double-tracked vocals on the chorus and a catchy piano riff. In other words, it sliced through the mix like an airport x-ray machine scanning your hand luggage. Despite this, the sound wasn't analytical; this speaker caught the attack of the instruments brilliantly and offered good dynamic contrasting.
So, what we have here is a classic high-end mini-monitor – albeit sporting twenty-first century technology and clothes. For all its fancy design features, it does what so many crave – which is to give a high-end sound from a super-compact package. Tonally it's very neutral – especially from the acousticWing driver – with just a touch of warmth and softness from the woofer. Because the cabinet is so solid, it's possible to tune some of this out with placement, yet you're always conscious that there's one super-fast driver in the speaker, and one 'mere mortal' drive unit. This, of course, is the classic problem with hybrid designs – such as speakers with electrostatic mid/treble panels or those with wide-range ribbons. Plus ça change, plus c'est la même chose – as your friendly local French philosopher would say.
Yet this never really distracts, because of the Zerø's so many other fine qualities. The more you listen, the more you appreciate its fine detail. Simple Minds' Someone, Somewhere, in Summertime is one of my favourite test tracks because it has a superficially bland analogue sound, a bit soft around the edges. But great speakers like this can unlock the mix, and suddenly it's a wonderland of subtle production cues and filigree detailing. The result isn't so much sensory overload as a new place to delve inside and explore…
For example, I loved the expressiveness of Jim Kerr's voice through the Wing. It was also set inside a more spacious vista, making his dreamy vocals sound more magical and mesmeric. At the same time, percussion was beautifully resolved with a lovely delicacy and smoothness to hi-hat cymbals. The kick drum was taut and possessed of a dull thud, just as the fashion was amongst studio engineers back then. Behind this, big swirls of sound from an early eighties analogue synthesiser swept the song along – and the Zerø was able to tell me all about the instrument's rich timbre, where so many small speakers make it sound airbrushed. Its resolving ability is top class then, giving a clean window on to the recording.
It's also a large one. This little speaker sounds way bigger than it actually is. Kate Bush's Snowflake was quite a thing to hear. The track is very close miked to her piano, with alternating vocals between the great lady and her son. This speaker was able to impart a high degree of intimacy, bringing the listener right up close and personal. My attention turned not just to the rich timbre of the piano playing, but the wonderful expanse of sound issuing out from my review pair of Zerøs. Not only does the speaker go wide, it offers excellent handling of depth perspective too; things aren't just rammed out at you. Instead, there's a sense that you can step in and peer around inside the recorded acoustic, without having it thrown out at you. It can also hang images very far back when called upon so to do. Factor in the aforementioned excellent off-axis response, and you can see why soundstaging is one of this speaker's many talents.
Frequency extremes are a mixed bag, but then that's the case with all small speakers. It does treble extremely nicely – it's certainly as delicate and many designs with ribbon tweeters, while being a little more etched and airy than my reference Quad electrostatics. There's a lovely tingle and sparkle to percussive instruments in the upper mid and treble, as evidenced by its handling of the drum kit work of Herbie Hancock's I Have a Dream. Not only is the texture of the ride and hi-hat cymbals a pleasure to behold, but the attack is quite something. Yet at the other end of the frequency spectrum, it was more of a mixed bag.
Upper bass is reasonably strong and arrives at much the same time as the treble and midrange driver – just as you'd want it. There's refreshingly little interference from the cabinet either, so I wasn't aware of it resonating in sympathy with certain notes on the double bass. Of course, there's a slight softening and smoothing of the bottom end – and it can't handle large tracts of low frequencies such as you'd get from electronic dance music for example. Yet's it's great for its size, and decently tuneful too. The extension is excellent considering its dinky dimensions – quite amazing really – yet I'd prefer a bit more ease of drive and a little less low bass.
It's all well and good to divide up all the aspects of this speaker's sound and comment on them as if you were judging an Olympic gymnastics performance – but in a way that misses the point. The real key to the Zerø is its overall blend of refinement, insight and excellent time-domain performance. This explains why it sounds fast and energetic without being forward or in-your-face. It's why you can run the gamut of your music collection and not feel like the speaker is going to do better with one genre of music than the other.
This combination of speed and dynamic impetus, plus its aforementioned translucence in the treble, midband and upper bass, marks it out as seriously special. Yet at the same time, any speaker with an internal cabinet volume of 2.6 litres – revolutionary drive unit or no revolutionary drive unit – isn't going to flap your flares, or put cracks on the plaster in your ceiling. Like every other seriously small speaker, it doesn't produce high volume levels and compresses things a bit at medium-to-high ones. That's physics for you, whether you like it or not.
Of course, every loudspeaker is a trade-off between size, power handling, performance and price – and that's the fun of the breed. By this, I mean that there's such a lot of choice and such a wide variety of compromises to be explored. The advent of the Wing Acoustics Zerø brings even more variety to the high-end mini-monitor mix – and that, as they say, is the spice of life.
Never forget though that it's a very niche design, and won't suit all tastes or requirements. It is currently only available via the company's website and is a steal at its price because what it does well, it does so very well. Indeed, it's quite a disruptive product which is bound to raise eyebrows in the industry. What happens next remains to be seen. Can we expect a larger, more user-friendly version to follow? Who knows, but what I can be sure of is that this little loudspeaker deserves to make a far bigger splash than its size suggests.
David started his career in 1993 writing for Hi-Fi World and went on to edit the magazine for nearly a decade. He was then made Editor of Hi-Fi Choice and continued to freelance for it and Hi-Fi News until becoming StereoNET’s Editor-in-Chief.
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