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Warwick Acoustics APERIO Electrostatic Headphone System: Review

At $36,000, Warwick Acoustics APERIO delivers one of the most spectacular headphone experiences we’ve ever tried.

Warwick Acoustics Aperio Headphone System

CanJam NYC 2024 takes place this weekend and it will be interesting to see if the show maintains the level of support that it received in 2023; EIC Ian White and Editor At-Large, Chris Boylan both agreed that it may have been the best Hi-Fi show they have attended in over two decades.

Demographics and changing listening habits have driven this revolution — and that’s a very good thing.

High-end audio brands have relied for far too long on the same customer base and not invested enough in the right products and marketing to build trust with the next generation of listeners.

The Head-Fi Revolution has opened the door for innovation in the headphone space and that has come at every possible price point; most consumers still consider $400 to be the ceiling for a headphone purchase based on the data that we have seen.

But what’s fascinating about the headphone community, is that the brands engineering expensive, and even cost-no-object products have begun to find an audience with younger buyers; and that’s not to say that most are running out and buying dCS digital front ends, Audeze LCD-5, and Meze Audio Empyrean II Headphones at this point of the journey.

But they are interested and events like Head-Fi’s CanJam Series strip away the intimidation factor when it comes to experiencing the best amplifiers and headphones that money can buy.

That isn’t the case at traditional high-end audio shows where newbies are subjected to six-figure systems and retailers focus their attention on older audiophiles with gear fetishism.

Warwick Acoustics Aperio Headphone Amp Closeup

Over the years, I have been fortunate to listen to some of the best products in the category at home which is a very different experience and whilst most of us will never be able to afford something like the $36,000 Warwick Acoustics Aperio Electrostatic Headphone System — I highly recommend that you do if CanJam will be a destination in 2024.

This system regularly draws comparisons to Sennheiser’s HE1 system which retails for…<choke>…$70,000 USD.

Warwick Acoustics (which should not be confused with Warwick Audio that manufactures rather lovely bass guitars in Germany) is a commercial spin-off of the Warwick University Engineering School (UK) and is based in the MIRA Technology Park, in Warwickshire.

If you are familiar with the Birmingham/Coventry/Leicester corridor, the facility is in-between all three cities.

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At CanJam SoCal in 2017, the Warwick Acoustics Sonoma M1 made its debut; the $5,000 headphone system which included a DAC and amplifier designed to compete with the Focal Utopia and Audeze LCD-5.

Warwick Acoustics Sonoma M1 Headphone System 2017
Warwick Acoustics Sonoma M1 Headphone System (2017 model)

The obvious benefit was that you got everything you needed minus a source for the $5,000 asking price.

The Sonoma M1 made some serious ripples in the high-end headphone pond which was a bold move for a brand that decided to dive headfirst into the deep end against the two biggest brands.

After its initial success, many wondered if the Sonoma M1 represented the best that Warwick Acoustics could offer; the new Aperio electrostatic headphone system was a complete cost-no-object redesign of that initial product, with the goal of creating the world’s best electrostatic headphone system.

Did they succeed?

Over the past few years, I I have been afforded the opportunity to audition the Sennheiser HE1, HiFiMAN Shargri-LA, Audeze CRBN, and Dan Clark Voce, which certainly gave me a benchmark with which to evaluate the Warwick Acoustics Aperio.

I also own a STAX 009/BHSE combination that ranks as one of the best (especially for the price) flagship headphone/amplifier combinations available.

To say that the Aperio needed to be spectacular to justify its $36,000 price tag would be an understatement.

Warwick Acoustics Aperio Headphone Amp Bottom


The Warwick Acoustics Aperio arrived in a large pelican case and the heft immediately made an impression; one will not be schlepping this on the train or airplane with them for use at the office or on vacation — unless it will be your only piece of carry-on luggage.

Opening the case reveals the amplifier/energizer and headphones with a second layer hidden beneath, containing all of the required cabling to wire the system including the headphone cable, power cable, and USB cable to connect a source.   

The energizer unit has a polished face and brushed aluminum shell (16″ W x 13″ D x 2.5″ H) with a series of controls on both the front and rear panels.

Warwick Acoustics Aperio Headphone Amp Top

The top and bottom surface have large vents for cooling and whilst the feet help ensure that there is adequate space between the bottom panel and the shelf beneath it, one should be make sure that nothing obstructs the ventilation.  

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The front face, from left to right, has the power switch, input selection, display screen, volume knob, left and right headphone outputs, and finally the headphone out / line out indicators and switch.

The rear panel includes the power input, USB, S/PDIF Coaxial, AES3 and DLNA-compliant ethernet digital inputs, followed by RCA and XLR analog inputs. There are a pair of RCA and XLR analog outputs.

Warwick Acoustics Aperio Headphone Amp Rear
Warwick Acoustics Aperio

Technical Details

Internally, the energizer houses dual-mono, 32-bit/384kHz DACs and a 64-bit fixed point processing DSP. Coax and AES3 inputs are restricted to 24-bit/192kHz PCM, whilst USB and the network support 32-bit/384kHz PCM and DSD up to DSD256.

The clock circuitry offers extremely low jitter and the DSP rivals those found in the best current digital audio workstations thus making a good partner for mixing and mastering work. 

There is no native MQA support; which means that you will have to supply your own DAC or network player that offers MQA.

The design of the DAC section allows the Aperio to keep PCM and DSD in their native format so DSD stays DSD until its final conversion to analog. It’s the same for PCM. Analog inputs never cross into the digital domain, thus keeping the signal paths as clean as possible. 

The energizer uses an 1800V(DC) bias charge and eight MOSFETs per channel in a fully balanced, Class A design.

The amplifier/energizer will output 15 watts/per channel and there is a 31-step volume control that offers excellent and precise control of the range.

Specs are equally impressive with a noise floor of -168dB/Hz, a THD+N of  <0.001%, and an SNR of -131dB.

Warwick Acoustics Aperio Electrostatic Headphones
Warwick Acoustics Aperio Electrostatic Headphones


The headphones look much heavier than they are because of the wide frame and Cabretta leather padded top-strap. The reality is that they only weigh 400 grams and feel extremely comfortable on your head; Warwick Acoustics achieved this through the extensive use of magnesium in the cups and gimbals which helped limit the weight and create excellent structural rigidity.

The top strap does a very good job of distributing the weight as well.

The Cabretta sheepskin earpads are rather deep and very comfortable; my ears did not touch the sides and I was able to listen with my glasses on without any issues or discomfort.

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Electrostatic Transducers

The transducers are the heart of the system and utilize Warwick’s patented Balanced-Drive High Precision Electrostatic Laminate (BD-HPEL). Electrostatic transducers have always been loved for their speed, clarity, and linearity, but often the very design of the electrostatic membrane being housed between two metal grids has been the weakness of some designs as the sound has to pass through those grids which can result in distortion.

Warwick’s HPEL transducers instead use a honey-comb design that uses a 15μm laminate film stretched over a Formex spacer to create tiny drum-skin (their words) cells that vibrate when energized.

There is a rear grid made of stainless steel, but no obstructive front grid like most designs between the transducer and the listener’s ear.

Much like the energizer which was designed for the cleanest signal path, the transducer is designed for nothing to come between the ear and the sound source. More details can be learned about the transducers from Warwick’s website here.

Warwick Acoustics Aperio Electrostatic Headphone Connector Cable


Warwick includes two custom designed cables (USB-A/B and Ethernet) that look heavier than they feel. Each is engineered with the finest quality connectors and shielding. Initially, I had concerns about potential microphonics, but they proved unfounded. For more details on the cables, visit Warwick’s website here.


Putting aside the excellent specifications for a moment, the reality is that any $36,000 headphone system has to deliver something that is well beyond what you can find anywhere else; and that includes loudspeakers.

What stood out almost immediately about the Aperio was its unforgiving nature with poor recordings; and we all own plenty of those.

The level of clarity, inner detail, and the ethereal nature of the sound can be utterly jaw dropping with good recordings, but it can also expose every single flaw and that includes sibilance, hiss, and even background noise in the studio or performance hall.

Warwick Acoustics Aperio Electrostatic Headphones

To say that you hear everything that was captured by the microphones is putting it mildly.

For some that will be illuminating and and a new form of discovery with recordings that you may have listened to hundreds of times over the course of your life.

For others, it will be a strong dose of reality and make one question why you thought something sounded great before.

The bass has very good depth and comes across as textured, detailed, and with excellent speed. That proved to be the case from the sub bass range through the upper badd.

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Warwick Acoustics Aperio Electrostatic Headphones Bottom

But it would fair to say that it also isn’t emphasised with the same degree of power as something like the Sennheiser HE1; which is the best we have heard in regard to the bass range so far.

The Aperio is closer to the STAX 009 and Dan Clark Voce in that regard.

From a mastering perspective, the the overall bass range is very neutral, clear, and detailed sounding — but those expecting intense, subwoofer-like low end response will be disappointed.

The Aperio emphasises quality over quantity and that proved to be the case from the bass range to the extreme treble.

The midrange is where these headphones are truly state-of-the-art; detail retrieval and transient response are spectacular all the way from the mid bass through the lower treble.

Lower strings are reproduced with accurate timbre and texture and singling out individual cellists in chamber orchestra pieces was rather easy.

The level of clarity and space between each musician was so wonderful that I started digging out classical recordings that I had not enjoyed in many years to see how they would sound.

What might surprise some, is just how much better the Aperio performed with even larger ensemble recordings with intense dynamic swings and pacing; the music never lost its focus or clarity and the bass range, whilst not overwhelming from an impact perspective, was so detailed and clean sounding.

Warwick Acoustics Aperio Electrostatic Headphones Top

Mussorgsky and Grieg soared with the Aperio; instrument separation and transient response were almost perfect (which is not a term I ever use) and nothing was hidden behind the more prominent voices in the mix.

Large brass sections were reproduced with excellent timbral accuracy and the Aperio was incredibly good at separating instruments from vocals in rather complex pieces.

Vocals are reproduced with the highest levels of resolution and clarity, but all of that was dependent on the recording and mastering.

Female vocals that are pushed forward in the mix come across that way; especially in comparison to their male counterparts, but understand that what you are hearing is the recording — not the Aperio that is deviating from its utter neutrality.

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Warmer sounding recordings are reproduced with all of the timbre, coloration, and detail that exists and it was fascinating to switch back and forth between male and female vocals and experience the wide range of mastering choices made in the studio.

The treble range can come across as slightly hot sounding, but that is completely dependent on the recording; the Aperio is faithful to the signal that is presented and one will experience some hardness in the top end as a result.

Warwick Acoustics Aperio Headphone Headband

Percussion snap and cymbals are rendered with absolute accuracy and the detail and airiness were as good as I have ever heard from any headphone so far — regardless of price. Jazz recordings with well recorded percussion will be a new experience for those who think they know “what they sound” like.

When I streamed a hi-res version of the Cowboy Junkie’s Trinity Sessions, I was struck by not only how well the Aperio reproduces both soundstage width and height, but also every last spatial cue on the recording. The reverberation and echoes within the church in downtown Toronto were reproduced with so much accuracy, that I found myself distracted from the music itself.

Perhaps one of the most spacious sounding pair of headphones we have tested so far and a new benchmark for me.

Warwick Acoustics Aperio Headphone Amplifier Left Front

Final Thoughts

For $36,000, the Warwick Acoustics Aperio needed to push the envelope and rank near the top of the headphone experience list.

Comparing the Aperio to my STAX 009/BHSE combination revealed that the Japanese system delivers a more fluid sounding presentation, but with less detail. And that’s saying a lot considering how exceptional the STAX headphones are with detail retrieval.

The STAX system is more forgiving of poor recordings and will come across to most listeners as having a smoother presentation and slightly darker tonal balance.

Because the amplifier/energizer is designed specifically for the Aperio, I was unable to try the STAX headphones to make a proper comparison; and that means I will have to wait for further Warwick Acoustics Headphones to emerge to see how other models compare.

Compared to the Sonoma (my first experience with Warwick) the Aperio is better in every category and has addressed the two primary complaints I’ve heard about the Sonoma. 

First, that the analog inputs could overwhelm the Sonoma’s amplifier, with the Hi/Low switching on the analog inputs, this is no longer an issue. 

The second criticism was that the Sonoma lacked some headroom and couldn’t hit hard enough during big dynamic shifts; the Aperio barely breaks a sweat with the same musical selections and required only turning the volume dial up to its midway point to achieve comfortable listening levels with excellent impact.

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Warwick Acoustics Aperio Electrostatic Headphone System

Having tried almost all of the top headphones in the world, there is a strong urge to say that the Warwick Acoustics Aperio Headphone system belongs in very select company and that it is worth its high asking price.

The reality is that it might be the best pair of headphones one can buy right now if your finances permit.

Forever grateful for the opportunity to audition them for two weeks and would strongly advise anyone with the chance to hear them (even if you can’t afford them) to savour every moment with them. Remarkable product.

Where to buy: $36,000 at |



  1. John Ratcliffe

    March 8, 2024 at 12:05 am

    Specifically what make and model are the DACs? I really hope a £30K+ device is not using ESS…

    • Ian White

      March 8, 2024 at 12:39 am


      The DAC chipset is a pair of dual mono ESS ES 9028PRO chips. But like anything, the implementation and all of their proprietary components have the final impact.

      The universal praise of this system is rather telling. For the price, it needs to be spectacular and according to Will (who invested last year in a dCS DAC for his reviews), the performance is top of the list.


      Ian White

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