Why Your Next Pair of Earbuds Might Not Have a Speaker in Them

Shenzhen earbud brand Earweiss has signed a strategic deal with Austrian MEMS specialist USound and plans to integrate USound's piezoelectric microspeakers into its next-generation in-ear monitors.

Earweiss, based in Shenzhen with R&D in Nanjing, makes heavily customised true wireless earbuds, with bespoke ear-moulds for anatomical fit, hearing personalisation through Berlin's Mimi Hearing Technologies, and industrial design closer to a boutique IEM than a typical TWS. The 2024 T1 paired Mimi's hearing profiles with a switchable bass and balanced voicing, and a "fresh air" venting system to keep the ear canal dry. The line now runs to the T2, T2 Pro and H3, adding adaptive AI noise cancellation, IDUN Audio head-tracked spatial audio and, in the case of the H3, biometric sensors for heart rate, blood oxygen, respiration and posture. For the next generation, the company wants to move away from conventional drivers altogether.

MEMS stands for Micro Electro Mechanical Systems. If you have used a smartphone in the last decade, you have been speaking into one — MEMS microphones are in pretty much every handset on the market. Making the same kind of chip work as a speaker has turned out to be a much harder problem, and it has taken the best part of twenty years to get there. The basic idea is to do away with the voice coil and magnet and replace them with a piezoelectric layer on a silicon substrate. Pass a voltage across it and the layer flexes. Arrange enough of these tiny cantilevers together, connect them to a membrane, and you have something that moves air — without any of the bulky mechanical components you would find in a conventional driver.

USound's drivers can be made under 1.6mm thick and weigh next to nothing. Because they are fabricated in a semiconductor plant rather than assembled by hand, unit-to-unit consistency is far better than a typical microspeaker. USound claims part-to-part variation of less than 1dB across the audible band, where conventional drivers can drift by ±3 to 5dB. They solder onto a circuit board like any other chip, which cuts assembly cost, and they produce so little mechanical vibration that they do not interfere with the ANC microphones sitting only millimetres away inside a modern earbud.

There are two main camps. USound, founded in Vienna in 2014, uses its piezoMEMS chips in a fairly conventional way — the chip drives a membrane that pushes air in the audible band, rather like a very small, very thin dynamic driver. Its rival xMEMS takes a more exotic route, generating ultrasonic pulses that are demodulated into audible sound by the air itself. Both are already shipping commercially: USound's drivers appear in QCY's in-ear buds, while xMEMS silicon has turned up in models from Creative and SoundPeats.

For Earweiss, the appeal is probably as much about packaging as sound quality. A driver that thin returns a chunk of internal volume to the product designer, which can go into bigger batteries, more sensors, or better antennas — and that matters when the roadmap already includes optical heart rate monitoring, posture tracking, and on-device AI. The fact that USound's technology sits behind more than 500 patents and is built on semiconductor-style production lines also helps when shipping a premium product at volume.

Earweiss’ CEO William Wang says the collaboration "opens exciting opportunities for innovation in the hearables space" and allows the two companies "to explore new product concepts that combine exceptional sound quality with compact form factors and modern wearable design."

For now, there is no product, no timeline, and no pricing — likely just a handshake deal. Still, the direction of travel is hard to miss. Between USound's growing list of Asian customers, xMEMS recently announcing mass-production readiness for its full-range Cypress driver, and partnerships like this one, MEMS is no longer a curiosity at the edges of the in-ear audio business.

For more information visit Earweiss