Electrostatic Reference

An electrostatic driver suspends a diaphragm thinner than a human hair between two perforated metal plates — the stators — and applies a high-voltage bias charge to the diaphragm. When the audio signal is applied to the stators as a push-pull differential voltage, the electrostatic field accelerates the diaphragm toward one stator and away from the other, producing sound with a linearity and speed that neither dynamic nor planar magnetic drivers can approach. The diaphragm has virtually no mass. It does not store energy. It does not ring. It simply follows the signal with a fidelity that makes every other transducer technology sound like a mechanical approximation of music — because that is what they are.

The Electrostatic Reference uses a 108mm diaphragm of 1.35-micron Mylar film with gold-sputtered electrodes. Gold was selected for its oxidation resistance and uniform conductivity — critical properties when the electrode must maintain a perfectly even charge distribution across its entire surface area. The stators are perforated steel, cryo-treated at -196°C to relieve residual stress from the stamping process and matched in pairs to a tolerance of 0.01%. Stator matching at this precision ensures that the push and pull forces on the diaphragm are identical in magnitude, which eliminates the even-order harmonic distortion that plagues electrostatic headphones built to looser tolerances. We are aware that some manufacturers match stators to 1%. We are also aware that 1% is one hundred times less precise than 0.01%. The arithmetic is not subtle.

The bias voltage is supplied by a dedicated energizer unit — a separate chassis that must be placed within cable reach of the headphones and connected to AC mains power. The energizer contains a single-crystal copper transformer wound at our Quito facility, which converts the incoming AC to a stable 580V DC bias with less than 0.3mV of ripple. Conventional energizers use polycrystalline copper transformers, in which grain boundaries between copper crystals act as micro-resistors that modulate the bias voltage at frequencies corresponding to the mechanical resonances of the transformer core. Single-crystal copper has no grain boundaries. The bias voltage it produces is, within the limits of our measurement equipment, perfectly smooth.

The ear chambers are lined with mu-metal — a nickel-iron alloy with exceptionally high magnetic permeability that redirects external electromagnetic interference around the driver rather than allowing it to impinge on the diaphragm. The shielding provides 80dB of EMI attenuation, which means that the electromagnetic noise from your smartphone, your Wi-Fi router, and the switching power supplies in every other device in your listening room is reduced by a factor of ten thousand before it reaches the diaphragm. The headphones connect to the energizer via a dedicated 5-pin cable that is incompatible with every other headphone amplifier on the market. This is by design. If you could plug these into a standard amplifier, you would, and then you would blame us for the result.