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Fujiya Avic Autumn 2016: the Sonoma M1 electrostatic system

  • hpfes2016-200A MetOPP film, 15 microns thick; a Formex (polypropylene) spacer; a stainless steel mesh for the ground — these are the material ingredients of Warwick Audio’s new ‘High-Precision Electrostatic Laminate’ (HPEL) driver, made on a roll-to-roll process in the UK. According to CEO Martin Roberts, the driver measures less than 1mm thick.

    This new Brit tech has already been deployed by Robert’s first customer, Sonoma Audio – they of DSD-editing workstation fame.

    The California-referencing but Colorado-headquartered company announced their first headphone product two weeks ago at RMAF 2016 – the M1 electrostatic headphone system – but Roberts joined Sonoma’s David Kawakami (ex-Sony) at Fujiya Avic’s headphone festival to help introduce the new ‘stat system to a Japanese audience where a local distributor has yet to be appointed.

    Word spread fast: in the 30 minutes I spent at the Sonoma table, I noted one solicitation for distribution in Singapore and a drop-in from a Stax representative.


    The M1 headphones sport the following materials: injected magnesium alloy earcups for their “excellent strength-to-weight ratio, high stiffness, superior acoustical damping and outstanding RFI/EMI shielding”; a nylon headband; German-made Ethiopian hairsheep leather pads and headpad.

    Powering Sonoma’s electrostatic headphones is a discrete FET Class-A “Energiser” amplifier encased in a shielded, machined aluminium enclosure, reportedly for better isolation from interference. Here lies a DAC also with access via USB and S/PDIF inputs. On the decoder’s specifics, Sonoma have opted to sidestep the chip model battle by specifying the manufacturer only: ESS Labs. Readers who care to play sleuth are advised that it is a 32 bit model with 129db.


    On the ground in Nakano, Kawakami’s emphasis was very much on his hardware’s hi-res performance. This aligns with his involvement in Gus Skinas’ Boulder-based DSD project of yore. Demo cuts were fed as single bitstreams from a pair of Microsoft Surface Pro’s to the M1’s energiser via USB. With all this talk of hi-res audio it’s easy to forget that the M1’s digital inputs also decode PCM.

    Tailoring the output response of the elecrostat ‘phones is the amplifier’s custom 64-Bit Double-Precision Fixed-Point DSP. Analogue inputs are digitised immediately upon entry via a 32-bit/384kHz AKM ADC. The question then itches: are incoming DSD streams not first converted to PCM for DSP manipulation? For those with an allergy to Sonoma’s non-native/ADC approach and don’t want a Stax stack, HiFiMAN’s Shangri-la is yours for US$50K. That’s ten times the green being asked by our UK/US partnership: US$4995.

    In the following video, Roberts introduces us to the Warwick Audio driver before giving a brief introduction to the M1 system itself, after which Kawakami (who lives in Tokyo) fleshes out the backstory:

    Further information: Sonoma Acoustics | Warwick Audio Technologies

    UPDATE from David Kawakami, November 2016: “We have pushed back the release of the Model One until 1st quarter 2017. Ironically, we’re pretty satisfied with the sonic performance of the M1 but there are still some fit and finish issues that we need to address before going to market. With the Sonoma name riding on this, we’re obsessed with getting the Model One as right as we can.”  


    Written by John

    John currently lives in Berlin where he creates videos and podcasts for Darko.Audio. He has previously contributed to 6moons, TONEAudio, AudioStream and Stereophile.

    Darko.Audio is a member of EISA.

    Follow John on YouTube or Instagram

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