Our projects

Holographic Whisper

up date 3. 11. 2017


Yoichi Ochiai, Takayuki Hoshi, Ippei Suzuki


Yoichi Ochiai, Takayuki Hoshi, and Ippei Suzuki. 2017. Holographic Whisper: Rendering Audible Sound Spots in Three-dimensional Space by Focusing Ultrasonic Waves. In Proceedings of the 2017 CHI Conference on Human Factors in Computing Systems (CHI ’17). ACM, New York, NY, USA, 4314-4325. DOI: https://doi.org/10.1145/3025453.3025989

We propose a novel method of three-dimensional spatial audio rendering by expanding the ultrasonic phased array technique. We employ an ultrasonic phased array as a holographic acoustic generator to focus ultrasound at arbitrary three-dimensional positions. The sound pressure at the ultrasonic focal points is sufficiently high to radiate audible sound based on the self-demodulation effect in air. Consequently, the ultrasonic focal points act as audible sound sources. This sound-point method enables us to control aerial audio distributions more flexibly and more precisely in comparison with conventional superdirectional (sound-beam) loudspeakers. This method can generate and vanish the sound sources freely in air. These point sound sources can deliver private messages or music to individuals.