This solid-state micro speaker aims to bring huge sound upgrades to earbuds, XR glasses, and smartwatches

There's no shortage of innovation in the audio industry, and one particular driver of progress is the introduction of solid-state audio tech. Most earbuds use regular audio drivers with a magnetic coil to generate sound, but the idea with silicon-based alternatives is that they use a piezoelectric drive in conjunction with ultra-thin membranes to make sound, and that's just inherently cool.

The brand making these drivers is xMEMS, and it just rolled out its latest product: the Sycamore. While its earlier Cypress driver is used in several earbuds — including the Creative Aurvana Ace 2 — and is designed for in-ear options, the Sycamore is aimed at the open-ear category instead, and is coming to earbuds, XR glasses, and smartwatches.

The timing of the launch is interesting, because there has been a steady increase in open-ear products, with Nothing and Bose catering to this niche. With the Sycamore, xMEMS is leveraging its “sound from ultrasound” design, and with the module coming in at just 1.13mm and weighing 150mg, it is three times thinner than a regular driver and one-seventh the size.

Ahead of the launch, I had an email interaction with Mike Housholder, VP Marketing and Business Development at xMEMS Labs, to understand how the Sycamore is different to the Cypress. Housholder noted that the new driver "represents the maturation of our ultrasonic transducer technology," and that changes to the "design and efficiency of the MEMS architecture" has allowed it to go from an in-ear design to open-air.

Sound quality is a key metric in micro speakers, and I was interested in learning about how something as small as the Sycamore is able to produce anywhere close to the same level of sound as a regular dynamic driver. "One of the key characteristics of our ultrasonic, modulated air pulse generation technology is that it exhibits a 1st-order low frequency degradation to provide a robust low frequency response as compared to conventional dynamic drive speakers which typically exhibit a 2nd-order (more steep) low frequency degradation," said Housholder.

As such, the brand is touting a similar mid-bass performance as regular drivers, with as much as 11dB headroom in the sub-bass extension. The driver comes with IP58 ingress protection, making it a decent choice for use in active earbuds.

Another issue that's resolved with the Sycamore is designing the shell of the earbuds. With regular audio drivers, brands focus on the design and materials of the shell, but Housholder noted that as MEMS speakers are not as prone to back volume due to the "stiff and rigid silicon diaphragm," this isn't as big a consideration. That's a big deal for an audio manufacturer, and with the driver itself not taking up anywhere as much room, it should free up additional space for a larger battery or result in buds that are smaller.

So when will we get to see products with the new driver? Housholder noted that xMEMS will showcase prototypes at CES 2025, with mass production starting in Q4 2025 and initial consumer products debuting in 2026. Considering the number of design wins the brand managed with its earlier drivers, it shouldn't have many problems with the Sycamore, particularly given that it can be used with XR glasses and smartwatches in addition to earbuds.