Hiraku Okumura

Rendering an immersive sound field using a virtual height loudspeaker: Effect of height-related room impulse responses

In order to provide consumers more enhanced and immersive experience in sound, most of the new multichannel reproduction formats highlight the significance of height-related information. In this paper, we investigated the influence of height-related room impulse responses when reproduced via various “height-loudspeakers,” including a virtual loudspeaker. Test participants listened to the corresponding sound fields and rated their perceived quality in terms of spaciousness and integrity. The results showed that perceived quality was affected by height loudspeaker positions and height signals, which was a specific room impulse response coupled with a virtual loudspeaker rendering process.

Investigating integration between auditory and visual location information presented in an augmented-reality device

Effective rendering technique of auditory information for an augmented reality (AR) device has been investigated. Researchers and industries are searching for new applications incorporating AR and Virtual Reality (VR) technologies, which provide enhanced user-experience of interactivity and intimacy. To utilize these benefits best, homogeneous integration between visual and auditory information is important. To date, the binaural technology based on head-related transfer function (HRTF) has been used to create immersive and three-dimensional audio objects for VR and AR devices. In this study, we compared the HRTF method with a stereophonic panning method that only controls Inter-aural Level Difference (ILD) for an AR device (a smart see-through glass) and investigated the precision of auditory information required for a coherent representation with a target visual image at the locations of 0 degree, -5 degrees, and -10 degrees in a counter clockwise. Auditory stimuli were rendered to have target locations...

Investigating physical parameters associated with listeners' perceived auditory depth

Recent 3D technologies allow viewers to perceive disparities in the depths of visual objects and to thus experience more realistic visual information. As for 3D auditory display, however, conventional loudspeaker layouts have not managed to manipulate perceived auditory depth in a sufficiently convincing way. Previously, we proposed a new method that utilizes a prototype electrostatic loudspeaker that is located above the listening position and generates auditory images similar to those of headphones. Using this phenomenon and amplitude-based panning, we were able to move auditory images along the line connecting the front loudspeaker and the listening position. In this study, we investigated physical factors that were idiosyncratic in electrostatic loudspeaker reproduction and that caused listeners to perceive sounds as being nearby. We both measured and simulated the loudspeaker-to-ear transfer functions using various types of loudspeakers at multiple locations, and extracted several physical parameters...