02 Nov An Innovative Speaker Architecture: The Distributed Piezo Drive
By: Mike Housholder, xMEMS Labs, Inc.
The Advantage of Distributed Piezo Actuation of xMEMS’ Speakers
From customers to journalists, from engineers to audiophiles, everyone is left astounded by the unrivaled audio quality delivered by xMEMS’ patented all silicon MEMS speakers. While they readily acknowledge the superior audio experience delivered by our MEMS micro speakers, many of them seek deeper insights into the underlying factors that contribute to this remarkable acoustic performance.
In this blog post series, we delve into the reasons why xMEMS’ true MEMS speakers offer exceptional audio quality and uncover the distinct advantages of our MEMS micro speakers over voice-coil speaker technologies, including dynamic drivers and balanced armature drivers.
How Does Distributed Piezo Actuation Work
One of the key performance factors behind xMEMS speakers’ superior audio quality is the way the speaker diaphragm is driven. xMEMS takes a major leap forward in speaker architecture by replacing the concentrated coil/magnet drive with a monolithic piezo drive. This innovative approach is built upon xMEMS’ patented micro speaker technology leveraging the inverse piezoelectric effect through piezo MEMS material. The inverse piezoelectric effect is created by applying electrical voltage, causing the piezoMEMS material to contract or expand, converting electrical energy into mechanical energy. This mechanical energy excites the integrated silicon membrane, enabling it to move air and generate acoustic sound waves.
Let’s explore how the distributed piezo drive elevates the consumer audio experience.
1. Unmatched Phase Consistency:
xMEMS micro speakers revolutionize traditional speaker designs with the utilization of distributed piezo actuation. The distributed piezo actuation, enabling exceptional phase alignment between the piezo layer and the speaker diagram, ensures that the piezo layer and the drive mechanism overlap almost perfectly, resulting in unparalleled phase consistency. By eliminating random phase response shifts, xMEMS micro speakers excel in maintaining precise phase characteristics across the audio spectrum.
2. Mitigating Speaker Break-Up:
As defined in a previous blog post, speaker break-up refers to the phenomenon where non-uniform behavior and distortion occur within the speaker diaphragm. Traditional dynamic drive speakers rely on a coil and magnet system, where a thin copper coil pushes on only a narrow section of the diaphragm to move air and generate sound. This concentrated force drive mechanism fails to provide direct support to the majority of the diaphragm, increasing the likelihood of non-uniform behavior and speaker break-up. Unlike traditional speakers, xMEMS micro speakers reduce the chances of speaker break-up with the help of distributed piezo actuation. The underlying piezo material supports and drives nearly 100% of the diaphragm surface, keeping the diaphragm uniform and linear during sound reproduction.
Figure 1: xMEMS piezo drive distributed across the speaker diaphragm surface
3. Achieving Wider Acoustic Bandwidth
The distributed drive mechanism employed by xMEMS micro speakers also enables speaker designs with multiple resonances which helps to achieve wider acoustic bandwidth. Traditional coil-based speaker operation is typically designed for a single mechanical resonance, resulting in limited bandwidth and sound pressure level decay at frequencies higher than the resonance point. In contrast, xMEMS micro speakers leverage their distributed piezo drive to achieve wider acoustic bandwidth, allowing for more immersive audio experiences that capture the full range of frequencies.
xMEMS micro speakers represent a significant advancement in audio technology, offering several performance benefits. With one of the most important key performance factors, the distributed piezo actuation, xMEMS micro speakers achieve exceptional phase consistency and wider acoustic bandwidth to ensure accurate sound reproduction across various frequencies. At xMEMS, we will continuously push the boundaries of audio technology to redefine consumer audio experiences in various applications.
Founded in January 2018, xMEMS Labs is reinventing sound with the world’s first solid-state True MEMS speakers for TWS and other personal audio devices. xMEMS has over 100 granted patents worldwide for its technology. The innovative, monolithic transduction architecture implements both actuation and diaphragm in silicon producing the world’s fastest and most precise micro speakers, eliminating spring and suspension recovery of coil speakers. This results in the most accurate time domain music reproduction, unmatched sound clarity, and an elevated sense of space. Please contact us to learn more.