BARCELONA — A new generation of smartphones has progressed to a point where consumers can expect to record footage in 4K video. But what about audio quality?
Several MEMS microphone vendors at the Mobile World Congress described “higher quality voice and audio” as the next frontier of smartphones.
Vendors gunning for MEMS microphone featuring better acoustic performance include Infineon Technologies, who provides its MEMS silicon to Hong Kong-based AAC Technologies, and a startup named Vesper, developer of the world’s first piezoelectric-based MEMS microphones. Vesper during the Mobile World Congress announced a partnership with AAC.
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For Vesper, the partnership deal is a breakthrough. AAC is known as one of the staple MEMS mic suppliers for Apple products (almost all generations of iPhones and old iPads), according to Yole Développement. Roger Tay, general manager and vice president of R&D at AAC, told EE Times that his company has more than a 50 percent share in the global smartphone market.
For AAC, which invested a minority share in Vesper in 2014, the partnership is also significant. The deal signals AAC’s interest in commercializing MEMS microphones deploying a piezo technology that’s fundamentally different from the capacitive MEMS microphones already shipping in massive volume.
Better acoustic performance
Infineon boasted at Mobile World Congress about its new MEMS microphones. The German company promises they will deliver “a maximum sound pressure level that’s around 10dB higher than the best microphones currently available on the market.”
Andreas Urschitz heads up
Infineon's Power Management &
Andreas Urschitz, who heads Infineon’s power management & multimarket division, told EE Times, “When kids go to a rock concert, they not only want to record good video but also excellent audio.”
Infineon’s silicon-based MEMS microphones pick up the user’s voice clearly even in very noisy public locations such as airports or concerts, or even in windy environments, he explained.
Infineon said its MEMS microphones which uses a dual back plate solution can not only deliver an industry leading signal-to-noise ratio (SNR) of 66 dB, but also an acoustic overload point of 135dB describing the sound pressure level, at which a noticeable distortion occurs.
With the dual back plate technology, Infineon’s engineering team has refined the technology so that the company can deliver MEMS microphones with differential output. “This allows for a symmetric output, which provides an almost undistorted signal even at high sound pressure levels and is very robust with regards to RF interferences,” according to Infineon’s spokesman.
Meanwhile, unlike the electrostatic transducer principle Infineon’s MEMS microphone is based on, Vesper’s solutions is based on piezoelectric, which Vesper said can make MEMS microphones intrinsically waterproof, dustproof and particle resistant.
Vesper shows off how the company's MEMS microphones continues to work after it is dipped into a water tank
Matt Crowley, CEO of Vesper, pointed out that dust can easily infiltrate the tiny hole occupied by a microphone in a smartphone, posing a danger of signal loss.
He explained that each smartphone can come with an array of eight microphones inside the unit for the beam-forming that enables noise cancellation. A failure of even just one microphone — caused by particle contamination — could cause a 90 percent failure rate in a smartphone’s microphone. Mic failure is the second biggest complaint among smartphones users, said Crowley, after cracked screens.
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