The diaphragm is the heart of the headphone, producing the waves our brains ultimately perceive as sound. In order to meet the acoustic goals we set for the 109 PRO, we focused our R&D efforts on materials research, looking for the perfect balance between mass and stiffness that would maximize the sonic abilities of the headphone.
Our search led to developing the 109 series Dual-Composite Diaphragm – a combination of Beryllium-coated polymer, cellulose - carbon fiber composite and copper-zinc alloy.
In a world of fast-paced technology, we bet on proven fundamentals. Our new 50mm dynamic driver, assembled and tuned with ultimate precision, allowed us to push the boundaries of speed, accuracy, and dynamic range.

Made of cellulose composite enforced with carbon fiber, the W-shaped dome is able to reproduce high-frequencies with incredible detail, clarity and definition. More durable than conventional alternatives used in dynamic drivers, yet lightweight, this composite helps us avoid resonances that may lead to harmonic distortion.
The ultra-thin torus surrounding the dome is composed of Beryllium-coated semicrystalline polymer, measuring 22 microns in thickness. With the Beryllium coating applied through Physical Vapor Deposition (PVD), we aimed to increase the stiffness and durability of the driver, while still keeping it light enough to achieve a fast transient response.
Beryllium's high damping qualities also help suppress unwanted resonances, giving the 109 PRO its neutral, vivid and transparent character. Around the membrane, the ring-shaped stabilizer made of copper-zinc alloy improves the absorption of vibrations to further reduce distortion.
The diaphragm is encased in a high-precision machined aluminum frame that has superior rigidity to typical plastics frames and retains perfect surface flatness, which is essential for the precision assembly with the diaphragm.
Through its open-back design, we wanted the 109 PRO to be vivid and exciting, empowering the listener to connect with music on a deeper level.
Carefully tuned by our in-house engineering team, it offers emotionally engaging sound with great detail, clarity and just the right amount of punch. Its organic character, paired with superior dynamics, excellent imaging, and full-bodied vocals bring soul-stirring details to life. Besides, it’s easy to drive from most devices, whether we’re talking portable sources or intricate home setups.
The spider-shaped structure and the acoustically transparent grill inside the earcup expose the driver from both sides, creating our most open pattern to date.
Following the principles of anthropometrics, we positioned the driver at a precise angle and distance from the ear, to achieve an ideal anatomical fit for the most natural listening experience possible.