Introduction to MEMS
Conventional voice coil speakers have been around for decades, and while they’re revolutionized audio equipment, they are clunky and are becoming outdated, we need an upgrade.
The world is now moving toward miniaturization, making tech smaller and smaller, easy to use, and easy to carry. This is where MEMS technology steps in, just a few months back xMEMS (a new start-up located in Santa Clara, CA) announced Montara, the world’s first true monolithic MEMS speaker. 
Image Courtesy: xmems.com
MEMS Speakers: What are they?
Contents
MEMS (Microelectromechanical systems) technology is not something new. We’ve seen their uses in devices such as microphones, accelerometers, blood pressure sensors, micro-valves, biosensors, and much much more. Now we are seeing their application in audio speakers. The result? Smaller, lower power-consuming speaker systems.
MEMS speakers make use of piezoelectric thin films that will deform when a voltage is applied to them. The deflection from here will displace the surrounding air and create sound waves.
Montara, the World’s First Monolithic MEMS Speaker
xMEMS has introduced Montara, which they claim is the world’s first true monolithic MEMS speaker. TIll now we’ve seen MEMS speakers which have been hybrid-build i.e. their actuator and diaphragm were not constructed in silicon.
The manufacturing of Montara MEMS speakers is very much different from conventional speakers. Montara is a monolithic type of speaker, instead of hybrid-MEMS speakers it is made from a single monolithic silicon chip piece manufactured via lithography. This makes it incredibly cost-efficient as it will eliminate the need for a complex manufacturing line.
According to xMEMS:
“By replacing decades-old, manually-assembled, highly-variable voice-coil speaker technology including dynamic drivers and balanced armature drivers, with a high-precision, high consistency, monolithic semiconductor process, we are bringing a new era in sound.”
Image Courtesy: xmems.com
MEMS Speakers vs. Conventional Speakers
MEMS speakers are different from conventional speakers and these differences make them a better alternative when it comes to audio devices.
For starters, they can be seamlessly integrated into an electronic PCB; in fact, they can be built on the PCB substrate. This is what allows them to be easily integrated into smaller-sized electronics such as wireless ear-buds, headphones, wearables, etc. 
USound integrates the amplifier and MEMS speaker on the same PCB substrate. (Image Courtesy: USound)
Similarly, the audio amplifier and MEMS speakers can be integrated on the same PCB substrate, also allowing for their use in smaller sized wearables.
MEMS speakers also consume lower power as compared to conventional speakers. This is due to their high intrinsic impedance which demands a lower driving current. Digi-Key tested the driving current of MEMS speakers by comparing them to a balanced armature, electrodynamic speakers. The results proved that MEMS speakers consumed the least power. Another reason why MEMS speakers are perfect for wearables which operate on smaller batteries.
Image Courtesy: Digi-key
Joseph Jiang, the co-founder, and CEO says:
“With on-the-go media consumption on the rise such as subscription music, podcasts, video, audiobooks, and mobile gaming, consumers are increasingly demanding enhanced audio quality and extended listen times between charges. Until now, the industry has relied on antiquated, centuries-old multi-component voice coil speakers requiring labor-intensive, high variability factory assembly lines. Our revolutionary Montara product is a game-changer for delivering a new combination of audio fidelity, size, energy consumption, and uniformity not possible with traditional voice coil approaches.”
Specifications and Features
This speaker comes packed with some pretty nice specs and features. If we talk about the sound quality, it offers a full bandwidth (20 Hz to 20 kHz) with a flat frequency response at >110dB SPL. It also has very low latency, according to xMEMS, with a <50µs group delay (mechanical latency) it allows for improved ANC of non-stationary noise. Along with this, it comes in a robust design, allowing for 10,000 g mechanical shock resistance.
Image Courtesy: xmems.com
The Montara module is IP-57 rated, making it both water and dust resistance without the need for any special protective covering or membrane. Coming in a small size (only 1mm thick), low power consuming, easily integrated design makes it an amazing product.
Availability
Image Courtesy: xmems.com
With samples and evaluation kits available, the mass production of Montara is expected to start by the first quarter of 2021. Montara will be available in two options XSM-2300 MONTARA (STANDARD) and XSM-2300-S MONTARA (SIDE-FIRING), The standard version is available for now.