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Aperio Headphone System

by Sonoma Acoustics


The revolutionary Sonoma M1 Headphone System, consisting of the M1 electrostatic headphones together with the companion Class A DAC/amp, has been optimized for today’s High-Resolution Audio formats. Every aspect of the system has been designed to deliver unparalleled levels of performance and sound quality.

New Transducer Technology
The M1 Headphone System is the world’s first headphone to use a High-Precision Electrostatic Laminate Transducer (HPEL) developed by Warwick Audio Technologies Ltd.  This patented technology ushers in a new paradigm in electrostatic transducers offering all of the benefits of traditional electrostatics, but manufactured with unprecedented consistency and matching between transducers.

Injected Magnesium Ear-Cups
With excellent strength-to-weight ratio, high stiffness, superior acoustical dampening and outstanding RFI/EMI shielding, magnesium is the perfect material in which to house the HPEL to ensure optimal performance. Low weight also contributes to outstanding headphone comfort.

Handmade Cabretta Sheepskin Ear-Pads
To ensure your comfort during long listening sessions, our ear-pads and headband are handmade from the finest Cabretta sheepskin leather, known for its light weight, durability and softness.

Custom Low-Capacitance Cable
In collaboration with Straight Wire inc,  we have developed a special ultra-low capacitance cable with high precision, self-latching connectors to guarantee ideal signal transfer between amplifier and headphone.

ESS Sabre Reference DAC
Two stereo DAC chips from ESS, the world’s premier DAC chip Manufacturer, are operated in mono mode to provide a measured 129 dB signal-to-noise ratio.

Precision CNC-Machined Aluminum Case
A precision CNC-machined, solid aluminum case not only creates a beautiful housing, but provides outstanding isolation from external interference sources.

Class-A Energizing Amplifier
A discrete, single-ended FET Class-A amplifier provides a high-performance, wide-bandwidth, very low distortion final drive stage, optimally matched to the HPELs.

Custom 64-bit DSP
All input signals are digitally processed using custom 64-bit double-precision fixed-point arithmetic. Fixed-point is known to be superior in the world of audio processing, and our 64-bit arithmetic exceeds the performance of most professional audio workstations.




Open-back; circumaural type


Balanced-Drive High Precision Electrostatic Laminate (BD-HPEL)

Effective Diaphragm Area

3570 mm2

Frequency Response

10 Hz – 60 kHz

Output Level (SPL)

Compliant with EN 60065/A12:2011 (EN50332) when driven by APERIO electronics (for all inputs); digital input: ∽ 104 dB; analog input: ≥ 106 dB (continuous, est.)

Ear and Headband Cushions

“Cabretta” top-grain, sheepskin leather; perforated surface on ear cushions


Polarized, 4-pin, self-latching connectors for left and right channels

Drive Cable

Dual mono, shielded, ultra-low capacitance; silver-plated OFHC ultra-fine stranded copper, with silicone insulation and Kevlar reinforcement; 2 meter length


405 grams (14.3 oz.), without cable


Balanced Analog Inputs

Dual (female) XLR jacks; switchable (high / low) input range; 18 dBu / 10 dBu

Unbalanced Analog Inputs

Dual RCA jacks; switchable (high / low) input range; 5.0 Vrms / 2.1 Vrms

USB Digital Input

Type B jack; USB 2.0; accepts digital audio formats up to 32-bit / 384 kHz PCM and DSD (DSD64/DSD128/DSD256) via DoP or Native

Network (Ethernet LAN) Digital Input

RJ45 jack; DLNA-compatible; accepts digital audio formats up to 32-bit / 384 kHz PCM and DSD (DSD64/DSD128/DSD256) via DoP or Native

AES3 (AES/EBU) Digital Input

XLR (female) jack; accepts digital audio formats up to 24-bit/192 kHz PCM

S/PDIF Coaxial Digital Input

RCA jack; accepts digital audio formats up to 24-bit/192 kHz PCM

Line Outputs

Balanced and unbalanced, high current outputs; +5 dB gain; switchable

Digital Formats

PCM: 16-32 bit / up to 384 kHz; DSD: up to 256 fs DoP and Native

Digital Signal Processing (DSP)

64-bit (double-precision) fixed-point processing at native sample rates

Switchable Gain

Rear panel switch; high level / low level selection for balanced analog input (professional audio and consumer levels) and unbalance analog input

Source Selection

Multi-position front panel selector with indicator LEDs for all sources

Level Control

Front panel, 31-position; digital and analog domain volume control (HP & Line Out)

Status Display

Front panel, 51 mm, full color, QVGA, TFT LCD (240 x 320 pixels)

Display Functions

Digital readout and bar graph of volume control setting; display of digital audio data format; display of rear panel analog input (gain) settings; display of Ethernet and USB data link transmission lock; display of detected fault modes and output clipping

Auto Fault Detection

Automatic detection, display and protection for: output amplifier clipping, unplugged connections and malfunctioning wiring, over-temperature conditions and internal electrical faults


2 x dual mono, 32-bit / 384 kHz DACs with balanced outputs, for PCM & DSD inputs


Balanced, discrete MOSFET, high-bias, single-ended Class A output; dual mono topology, including power supply; 1800 VDC bias (charge) voltage

Distortion + Noise

< 0.001%


> 65 kHz


CNC-machined 6063 aluminium; earth-grounded

Power Supply

External: world voltage compatible (90-264 Volt AC, 50-60 Hz); 24 Volt DC, 200 VA (8.333 A), fixed frequency, class B-compliant SMPS

Internal: isolated, dual mono; switching and ultra-low-noise linear regulation

AC Mains

Types B, G, F, I; IEC-60320 C14, earth- grounded power cable; 1.5 meter length


H x W x D: 68 mm (2.68 in.) x 413 mm (16.26 in.) x 351 mm (13.82 in.)


7.4 kg (16.28 lbs.), without Power Supply

The above information is from the manufacturer.
Have a question? Connect with our Audio Gurus at 800-328-9973 or 215-862-4870 or Send email or use Contact form. You can also take advantage of our system matching expertise with a Free System Consultation.

Warwick Acoustics Aperio Headphone System

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  • Warwick Acoustics Aperio Headphone System

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