MEMS microphones, used in best-selling devices like Apple's iPhone, face a promising future as the market is projected to keep climbing in the coming years, according to a new report from IHS. Global revenue for MEMS microphones is forecast to reach $1.04 billion this year, up a robust 24 percent from $837 million in 2013. Less than a decade was needed for the MEMS microphone market to cross the billion dollar threshold. While this year continues the galloping growth the industry has seen during the last few years, the rate of expansion is slowing as revenue has expanded. Even so, the next few years will continue to yield solid results for the business, and revenues by 2017 will amount to a projected $1.37 billion, equivalent to a five-year compound annual growth rate (CAGR) of 18 percent from 2012 to 2017. Shipments at the end of the forecast window will equal 5.4 billion units, up from 1.9 billion in 2012.
"The MEMS microphone segment has successfully capitalized on the value delivered by audible improvements in microphones to propel the industry forward," said Marwan Boustany, senior analyst for MEMS and sensors at IHS. "Especially in an age in which devices are increasingly uniform, sound can be a real and important differentiator, in features such as voice command or crystal-clear audio in high-definition video -- qualities that are possible only through high-performance MEMS microphones." Handsets and tablets account for the majority of MEMS microphone consumption, and Apple and Samsung are the biggest buyers at present, Boustany noted.
Audibly improved: the difference matters
Two of the main measures for MEMS microphone quality are signal-to-noise ratio (SNR) and the maximum sound-pressure level (SPL). These define the lowest and highest sound levels, respectively -- or dynamic range -- that can be gauged by a microphone with a linear response. The measures apply to both analog and digital MEMS microphones, and have been used as the basis for microphone quality in marketing by firms such as Nokia and HTC.
At the top performance level, microphones with very high SNRs feature a signal-to-noise ratio level of greater than, or equal to, 64 decibels. These are the microphones projected to have the greatest growth in the coming years, with an estimated five-year CAGR of 40 percent from 2012 to 2017.
In the past, microphones with low SNRs, featuring signal-to-noise ratios of less than 60 decibels, were the standard devices in many handsets. Acceptable for phone calls, low-SNR microphones have shown their limitations in performance, as in cases where there is some distance between the source of the recorded sound and the microphone, such as for video recording and voice commands. In such instances, low-SNR microphones can miss out on the lower volume elements of the sound, which can result in a loss of data important for voice commands and a degradation of the richness in recorded sounds for video.
Low-SNR microphones are also not up to the task of ambient noise cancellation, in which the microphones help to neutralize surrounding noise levels in order to better focus on the immediate sound intended for transmission or reception. Here again, microphones with higher SNRs are the key factor for an improved listening experience, Boustany said.
Very-high-SNR microphones were first used in 2012 by Apple in the iPhone 5, and subsequent generations of the popular smartphone continued to utilize these MEMS microphones. After Apple, Samsung joined in, using very-high-SNR MEMS microphones in its S4 and Note 3 flagship handsets. Together the two companies made up 96 percent of revenue for the very-high-SNR MEMS microphone market in 2013.
Another advantage of very-high-SNR microphones is enhanced support for voice commands, helpful for Apple's Siri or Google Now. The Motorola Moto X, for instance, includes multiple very-high-SNR microphones that improve the handset's ability to capture voice commands.
Between the very-high-SNR and low-SNR categories sits a third class of MEMS microphones, the high-SNR devices with signal-to-noise ratios between 60 and 64 decibels, which is what lower midrange devices may choose to transition from low-SNR microphones. Growth of this segment during the next few years will be lower than that of very-high-SNR types, but higher than in the low-SNR segment that is headed for decline.
Finding their way into the most popular consumer gadgets
MEMS microphones are deployed the most in handsets and tablets, which last year accounted for 93 percent of revenue in the very-high-SNR microphone segment. Apple and Samsung each have up to three microphones for their handsets that could possibly climb to four, and the multiple numbers help increase the overall revenue for MEMS suppliers.
The rapidly growing tablet space is also a vigorous market driver, with the Apple iPad product line now outfitted with two microphones and with Samsung also adding multiple microphones to some of its tablets.
Very-high-SNR microphones are making inroads into hearing aids, too. The ReSound LiNX, for instance, uses two such devices, for noise cancellation and improved performance, with an additional beneficial capability that ties in Bluetooth connectivity with an iPhone -- enabling the hearing aid to act as a headset as well. High-performance MEMS microphones will also become increasingly prominent in the automotive space, helping to support voice commands and hands-free calling. Harman, for example, has announced the use of two MEMS microphones for such use in Germany's Daimler vehicles, which will be in production in 2016.