Holographic Whisper is a sound technology in which sound can be generated in an empty space by creating a focal point of ultrasonic waves. What content can be heard by whom is controlled through appropriate switching of the position of sound generation, audio play, and volume.
It is possible to create a strong sense of immersion by coupled with visual information and location information, such as making the viewer hear sound from the direction one wants the person to pay attention to in an image or delivering information only when one passes by a specific location in an event venue. Additionally, it is possible to deliver sound to only a specific person by lowering the volume. In this way, it is possible to realize highly confidential information transmission or communication considering the leakage of sound to people nearby. Moreover, by switching the position of the focal point of ultrasonic waves, it is possible to deliver different audio to different individuals.
＜ Case ＞
■ Case 1.
In the case of conventional superdirectional speakers, sound can be heard by all the people standing in one straight line. You want to communicate specific information only when the person is in front of an exhibit in a gallery by determining not only the direction, but also the distance. Moreover, because it is difficult to hear the name being called when a café space with many seats is crowded, you are looking for ways to direct sound only to a specific seat or table, so that the people around that location only can hear the name being called.
■ Case 2.
In case of presenting sound in conjunction with images, you are looking for ways to change not only the targeted direction for the audience, but also introduce the perception of change in distance from the sound source, such as a sound ringing close by or a sound that can only heard indistinctly as if far away.
■ Case 3.
When the drivers of small vehicles, such as a taxis, conduct operational reporting, the ensuing conversation over the radio installed in the car is overheard by the passengers. You are looking for a technology that allows clear conversation without annoying the passenger. In the case of a family riding in a private car, you are looking for ways to realize a sound environment boundary, such as car navigation sound that can only be heard from the driver’s seat while music is played only for the listeners in the back seat.
＜ Theory ＞
■ Delivering sound End to End with non-audible sound as the carrier
Because ultrasound has a very high frequency, it is not audible to the human ear. However, it is known that when the acoustic pressure of the ultrasonic waves is high enough, frequencies other than ultrasound are produced due to the nonlinearity of air. As an application of this, research is being conducted on technology to emit audible sounds in the air using ultrasound modulated with audible sound. We have been able to deliver sounds to a specific position by combining this principle with the technology for controlling the distribution of ultrasound.
■ Generating sound source not as a line but as a point
In our technology, we utilize multiple ultrasonic transducers, each of which is pulsed individually with different timing. Although the ultrasounds emitted by each of the transducers are feeble, by interfering with each other, they reach a level strong enough to emit audible sound only when a focal point is established. Even more detailed targeting is possible, because the audible range can be expanded or contracted by changing not only the position of the sound source, but also the volume of the audible sound played.
■ Main accomplishments
[Award] Ministry of Economy, Trade and Industry, Innovative Technologies 2016 Selection (20/80) / September 2, 2016.
[Conference] CHI Conference - Denver, Colorado (USA), May 6-11, 2017.
[Exhibition] Digital Content EXPO, Miraikan – The National Museum of Emerging Science and Innovation, October 28, 2017.
[Exhibition] Image and Matter - Cyber Arts and Science Towards Digital Nature, Kuala Lumpur (Malaysia), December 11, 2016 – January 14, 2017.
[Exhibition] SEMICON Japan 2016, Tokyo Big Sight, December 14-16, 2016.
[Exhibition] Digital Content EXPO, Miraikan – The National Museum of Emerging Science and Innovation, October 27-30, 2016.
[Exhibition] ZOKEI NEXT 50, Tokyo Zokei University Graduation Works Exhibition, Aoyama Spiral, October 25 – November 3, 2016.
[Exhibition] Ars Electronica Festival 2016, Linz (Austria), September 8-12, 2016.
[Media] logmi, February 10, 2017.
[Media] ASCII Research Laboratories, Inc., September 27, 2016.