(Image courtesy of Vesper Technologies).

Vesper Technologies to Increase MEMS Microphone Production

June 5, 2018
Vesper Technologies Aims to Amplify MEMS Microphone Production

Last month, Vesper Technologies raised $23 million in funding from many of the major players in voice-controlled devices. Amazon’s Alexa Fund, Bose Ventures, Synaptics and Baidu all invested in the MEMS microphone maker. Leading the funding round was American Family Ventures, the venture capital division of insurance giant AmFam.

As voice assistants like Amazon Alexa and Google Home make talking to smart speakers more commonplace, the Boston, Massachusetts-based company is trying to capitalize on the push to control everything from televisions and wearables to refrigerators and headphones with a few simple spoken commands. The startup makes microphones that consume much less power than traditional ones.

The company expects the first products using its new microphones to reach the market before the end of the year. And to support customer volumes, Vesper will use the new funding to ramp up production from the several hundred thousand microphones it shipped in the first half of the year to several million per month, said Vesper’s chief executive Matt Crowley in an interview.

Crowley claims that current capacitive MEMS microphones consume too much power, lack durability, and have low dynamic range. These problems are connected to the fact that they are manufactured with two parts: a diaphragm and a back plate. Not only can water and dust get stuck inside the space between the back plate and the diaphragm, hurting reliability, but air pressure can accumulate inside the cavity, dampening the sensor’s sensitivity to voices.

Conversely, Vesper's microphones do not have a back plate. Instead, they use a single diaphragm based on piezoelectric materials that generate a small voltage when pummeled with sound waves, cutting power consumption and even enabling the microphone to wake up the system. The simple structure improves durability as well as signal-to-noise performance, which allows the sensor to isolate voices from farther away and sense a wider dynamic range of voices clearly, said Crowley.

The microphone also lets systems stay powered down and wake up when they hear a voice command, something that Crowley calls quiescent sensing. “We’re replacing buttons that you press with your finger with buttons you press with your voice,” Crowley told Electronic Design. “The power difference is between having the whole system up and running, versus only having the low-power microphone running,” he said.

And the company’s business is budding. Last year, the company shipped more than a million microphone wafers to partners including ACC Technologies. Vesper has since started to handle testing and packaging so that it can supply customers with complete microphones, including the wake-on-sound VM1010 microphone, which accounts for around 80 percent of the sensors it sells. The company’s other products are the analog VM1000 and digital VM2000.

“Vesper has the technology to disrupt established MEMS microphone players and some sweet spots to run after,” said Guillaume Girardin of semiconductor research firm Yole Développement, in a statement. “People are now expecting a ramp up in the production to fulfill market needs, especially in the smart speakers or wearable markets.”

Vesper has friends in high places. Amazon’s Alexa Fund, which assisted with the company’s $17 million funding round in December 2016, pushes Vesper’s microphones to potential customers when it considers the technology a good fit. Vesper has also partnered with chip companies including Ambiq Micro and Synaptics on development kits that help integrate voice assistants like Alexa into embedded devices. Crowley declined to comment on whether its microphones are used in any Amazon products.

The company, which was founded in 2009, is trying to close the massive gap with market leader Knowles, which ships more than a billion capacitive MEMS mics every year. While Vesper has pushed into new materials to boost the performance of voice assistants, Knowles is working to pair its microphones with audio processing software that can amplify faint sounds and suppress loud chatter in noisy spaces.

Paris, France-based Yole Développement projects shipments of MEMS microphones to reach 5.6 billion units by the end of the year, generating revenues of $1.1 billion. Device manufacturers are adding more and more microphones to voice-controlled devices in an attempt to improve the clearness of different voices and identify the direction that they came from. And that plays into Vesper’s strengths.

“As the number of microphones increases, the need for the reliability of the individual components increases,” explained Crowley. “If you have an array of a dozen microphones, and you have drift in one microphone, the whole array suddenly starts pointing in the wrong direction.” He added: “The array just stops working properly.”

Crowley told Electronic Design that it would release a new microphone line by the end of the year focused on ultra-wideband dynamic range so that it can scrub speaker distortion and suppress wind noise. He said that the company is also considering building modules that package its microphones together with sensors that measure things like temperature and humidity.

Because of the power consumption differences, the company’s microphones are not drop-in replacements for capacitive sensors. But Crowley said Vesper will use the funding to expand implementation support for customers and hire an additional 15 employees to fill out its engineering and sales teams. Vesper, which currently employs 27 people, will also expand its sales operations in South Korea and China.

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