Audeze is well-known and well-liked for its excellent planar-magnetic headphones. With its CRBN (pronounced “carbon”) electrostatic headphones, the business is venturing into new terrain.

Planar-magnetic (PM) and electrostatic (ES) headphones are similar in that they both have a relatively large, thin diaphragm hanging between two acoustically transparent components known as stators.

The stators in PM designs are permanent magnets, and the diaphragm has a flat, conductive ribbon that runs the length of it. The electrical audio signal is carried by the ribbon, which generates an oscillating magnetic field that interacts with the stators’ static magnetic field to drive the diaphragm back and forth.

Thanks to a DC bias voltage from a specific amplifier, the diaphragm of ES headphones produces a static electric field (thus the name “electrostatic”), and the stators convey the audio signal in opposite phases to each other. The oscillating magnetic fields that result interact with the diaphragm’s static field, moving it back and forth.


In both circumstances, the oscillating diaphragm produces acoustic sound waves that reach the ear.

ES headphones require a special amp that delivers a DC bias voltage to the diaphragm, which must obviously be conductive. Whereas PM headphones may be driven by any normal headphone amplifier, ES headphones require a special amp that supplies a DC bias voltage to the diaphragm. The diaphragm is a plastic film with a coating of conductive material put on its surface in practically all ES headphones to date.

Unfortunately, coated diaphragms have a number of drawbacks. To maintain an even force throughout the entire diaphragm, the layer must be exceedingly uniform and only a few tenths of a nanometer thick.

At a large scale, this is extremely difficult to achieve. Furthermore, if the diaphragm goes too close to the stator, it might attach to it and harm the ultra-thin metal layer. Finally, because there is so little metal, it might corrode and wear away over time, especially under less-than-ideal conditions like excessive humidity.
This is where the CRBN makes history. Instead of a conductive layer on the diaphragm’s surface, Audeze created a method in which carbon nanotubes are suspended throughout the diaphragm’s polymer substance. The conductivity of the diaphragm material is determined by the density of nanotubes within the polymer, which can be carefully regulated.

The driving force is entirely even without the distortions associated with normal coatings because the charge is dispersed consistently throughout the film. Finally, the diaphragm made of carbon nanotubes is impervious to the elements and will not degrade over time.

The CRBN is the result of a study started by UCLA clinicians who desired a headphone that could be used in MRI (magnetic resonance imaging) equipment. Anyone who has had to endure an MRI scan knows how claustrophobic and noisy they can be—sound pressure levels can reach 120 decibels!


Headphones can help with these issues by playing soothing music while also providing active noise cancellation. They can also give acoustic stimuli that activate specific parts of the brain, which are then scanned for diagnostic purposes using an MRI machine.

Unfortunately, typical headphones do not perform well in an MRI machine because they are often made of ferrous metals, which are sensitive to high magnetic fields. Furthermore, while the conductive layers in most ES headphones are gold or titanium, which are not affected by magnetic fields, they can cause “shadows” in MRI pictures. Finally, headphones for usage in MRI machines must be extremely durable and capable of reaching high SPLs with low distortion and active noise suppression in order to battle the machine’s high noise levels.

Audeze’s carbon nanotube technology solves these challenges flawlessly after three years of research and development.

Audeze believed the technology might be employed in audiophile headphones once it was refined, and the CRBN was born. The open-back, circumaural (around-the-ear) headphone has custom-designed leather earpads and weighs only 10.6 ounces. It requires an amp that feeds Pro Bias voltage to electrostatic headphones via a standard 5-pin connector and uses the typical Pro Bias voltage of 580V.

The frequency response is reported to range from 15Hz to 40kHz (no tolerance given), but this only relates to the individual drivers.

The frequency-response curve is flat down to 20Hz using a B&K HATS (Head And Torso Simulator) system, which incorporates a microphone near the eardrum of a simulated ear. That’s odd for ES headphones, which usually have a low-end roll-off. With a spike at 3kHz and a roll-off above 10kHz, the rest of the response closely follows the Harman headphone curve.

ES headphones have a lower dynamic range than most dynamic or PM versions, and the usage of 580V as a bias voltage reduces the dynamic range even more when compared to the earlier norm of 800V.

Furthermore, dynamic and PM headphones tend to have more bass, while Audeze developed the CRBN to compensate for this. ES headphones, on the other hand, frequently create an ethereal feeling of “air” that other technology cannot imitate.

The Audeze CRBN isn’t cheap, with a stated price of $4,500—and you’ll still need an amp to go with it. A secondhand Stax amp on eBay can cost anything from a few hundred dollars to $5,100 or more for a Mjölnir Carbon amp. Keep in mind that the Sennheiser HE 1 currently sells for $59,000, which includes the amplifier.

At Audeze HQ, I heard a short demo of the CRBN, and it sounded fantastic.




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