June 15, 2021
Most components in consumer electronics are silicon-based. The last component that is still manufactured traditionally is the loudspeaker — until now. USound is leading the revolution of the global speaker market, being the first company to introduce MEMS loudspeakers to the mass market. The thin form factor and wide bandwidth of USound MEMS speakers enable…
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April 4, 2019
USound’s technology is based on piezoelectricity. Crystals with these properties are for example aluminium nitride (AlN) or lead zirconate titanate (PZT). These materials expand or shrink in an electric field. In a practical configuration, such an electric field is generated between electrodes, covering a piezoelectric layer. This stack is put on top of a substrate…
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As everyone knows the further away a sound source is, the quieter the sound will be. This is due to the surface expansion of the affected space. One can imagine an ideal point source producing a sound field that moves like an expanding sphere into all 3 dimensions. This means that for doubling the distance…
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The baffle measurement represents a special case of free field measurement. However, in this case, the sound is propagating through the air as a wave. In case of miniature speakers, the transition between mechanical movement and air pressure is poor, that’s why very high excursions are needed to produce high SPL (e.g. very rough example:…
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Acoustics is based on vibrating air pressure. The higher the amplitude of the vibration the higher the SPL. To create these pressure changes a moving membrane is used in loudspeakers. Paying a closer look at the situation, one can see, that when the membrane moves forward, an over-pressure created in front of the membrane. On…
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June 4, 2018
First, we should clarify how power consumption is typically measured with electro-dynamic speakers or BAs. Since the impedance of these speakers is roughly constant over frequency (typically 4, 8 or 32Ω), this impedance value is taken as “nominal”. With this, a very simple transformation from a result obtained with a constant voltage into a result with…
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