Solid-state speaker technology is growing less expensive with the introduction of xMEMS' Lassen tweeter. The new micro-speaker, which is smaller and more accurate than a conventional tweeter, should debut in earbuds later this year or early next year.
The Lassen micro-speaker measures just 3.2 x 5 x 1.15 millimeters, which is roughly the size of a grain of rice. Still, it boasts 115dB SPL in the 6kHz to 20kHz frequency range, “delivering sound quality that exceeds that of legacy tweeter speaker technologies,” per xMEMS. And, unlike previous the xMEMS Cowell and Muir solid-state speakers, Lassen does not require a separate piezo amplifier chip—it takes up less space than other solid-state audio solutions.
Of course, Lassen is a tweeter, not a full-range driver. It isn’t designed for standalone use. Rather, it’s meant to be paired with a conventional woofer in a “two-way speaker” configuration (like a bookshelf speaker). Most earbuds rely on a single full-range driver, which is naturally prone to some distortion and inaccuracy due to physical constraints. A “two-speaker” configuration is generally considered the better option, as the tweeter can focus on treble frequencies while the woofer handles mid-range and bass, though this configuration is uncommon in earbuds due to the size requirements of conventional speaker cones.
xMEMS-equipped earbuds that use a two-speaker configuration, such as theCreative Labs Aurvana Ace 2andSoundpeats Capsule3 Pro, are universally praised for their sound quality. The new Lassen tweeter has the potential to reduce the cost and size of such earbuds, which will (presumably) increase their appeal.
Though, admittedly, full-range speakers are more than good enough for the average person, and a two-speaker design does not guarantee high-quality audio. A poorly-fitted earbud will always sound bad, as will one with poor amplification, excessive software meddling, a crappy Bluetooth radio, and so on.
“The industry has embraced the superior audio quality of 2-way speakers in TWS earbuds, as well as the ability of xMEMS speakers to enhance that quality … Lassen is a revolutionary design based on a proven platform. It will bring the benefits of 2-way earbud audio to a broader market by eliminating extra cost of the piezo amplifier and minimizing the space and power required to deliver truly immersive TWS sound experience.” - Mike Housholder, VP, Marketing & Business Development at xMEMS.
I recently met with xMEMs for a hands-on demonstration at CES 2025. The company showed me an assortment of hacked-together headphones, 3D-printed earbuds, and other prototypes used for internal testing or corporate sales pitches. And, honestly, the whole thing felt like an hour-long magic trick. I still don’t understand how a flea-sized silicon wafer can produce loud, accurate, distortion-free audio, but I’m confident that these solid-state speakers will contribute to major advancements in the consumer electronics industry, particularly as smart glasses and other next-gen wearables gain traction.
For reference, xMEMS develops a range of piezoMEMS silicon systems, not just micro-speakers. One of the things that impressed me the most at CES 2025 was thexMEMS Active µCooling fan, an all-silicon wafer that measures 1mm thin and can provide airflow for super-slim devices, such as phones or SSDs. These devices typically rely on passive cooling and can overheat easily, meaning that µCooling fan could substantially improve their performance without infringing on their usability. The solid-state fan, like xMEMS' speakers, could also help existing devices achieve a slimmer form factor.
xMEMS is currently showing samples of the Lassen tweeter to audio manufacturers and other relevant parties. Mass production of Lassen begins in September, so the first earbuds equipped with this tweeter will probably arrive at the tail end of 2025 or the beginning of 2026. Partner brands have not been announced, though Creative Labs and Soundpeats seem like likely candidates.
