Modulated ultrasound speakers – A common framework for analyzing air pump speakers

In this article we describe a new approach to sound generation based on active modulation of ultrasound. Active modulation of ultrasound provides an alternative to dynamic drivers and enables to reduce the size and volume of speakers. This feat in apparent contradiction to basic acoustics. In the article we provide for the first time an explanation of the underlying physics of modulated ultrasound speakers using a holistic lumped element model. Using the model, we explore different archiectures and highlight an archicture providing maximal sound pressure level for a given membrane area and displacement. Devices implementing the architecture were fabricated using MEMS technology. The sound pressure level response of the fabricated devices is compared to simulations highlighting the unique properties of the modulated ultrasound speakers. • Comparing first and second generation MEMS speakers. • New method for sound generation based on modulated ultrasound. • Utilizing ultrasonic micro diaphragms to produce sound.