With our sound processing, we are aiming to realize the world where easy to hear, easy to understand, pleasant sound can be listened to naturally, without effort. To achieve this, we are considering how to expand effective areas and realize three-dimensional localization control in addition to the functions we already provide for giving sound a sense of direction.
Our Sound images with controlled stereophony are more robust than the localized sound created using absolute sound pressure methods, in the viewpoint of hearing position changing, but the degree of auditory localization falls if listeners move far from the sweet spot. If it were possible to expand the range over which the effects of auditory localization could be enjoyed, the directional sound would be effective everywhere between two speakers. This would decrease restrictions on usage situations, such as the positions and postures of listeners. For example, people in the same room could feel the same sense of directionality and presence of the sounds using the same speakers.
Furthermore, control of the horizontal localization of sounds has already been realized, but it is known that the control of vertical sound localization is more technologically challenging. More natural "sound arrangement" could be achieved if it would be possible to perform three-dimensional direction control, including vertical sound localization, through fixed-position speakers located at a distance from the listener’s ears, not just through headphones or earphones. We think that one of the keys of accomplishing this lies in the acoustic effects of the ear canal, so we are currently developing technologies.
Continuing to enhance the robustness and freedom necessary for listeners to be able to effortlessly enjoy sound localization, the combination of sound images with controlled stereophony technologies related to output, sensing technologies for acquiring input, and state analysis technologies that link them, would realize natural sound output that is optimized for the states of listeners.
This has the potential to make it possible to use audio information in new ways, and for a wider range of applications, including situations in which listeners are not using earphones or headphones. For example, the voice of online classes or meetings could be heard clearer and easier to understand.
It could also enable several people to share a more natural sense of experiencing the same "space" in usage situations such as virtual reality-based telecommunications, remote experiences, and the metaverse. Providing situation-adjusted sounds, voice announcements, and information also could be possible. This could be done even in places in which the locations of listeners are not strictly fixed, such as in offices, elevators, near signs, and other building and facility infrastructure, or in bathrooms, washrooms, kitchens, entryways, television viewing areas, and other housing environment. Even with the information devices with speakers inside, like smartphones and tablets, users could enjoy listening to directional sounds content while in a free, relaxed posture.
Toshiba will continue exploring more applications of Soundimension and developing the technologies to offer new sound experiences.
In part one, we provided an overview of our sound technologies. Here, in part two, we have explained one of Toshiba’s two core sound technologies, sound images with controlled stereophony technology. In the third article, final part of this series, we will explain Toshiba’s other core sound technology, sound field control for region separation technology.