Mikio Tohyama

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Interaural cross-correlation coefficients (ICCCs) were measured in stereo-reproduced fields where a KEMAR (Knowles electric manikin for acoustic research) was located. These ICCCs were then compared with those in an ideal, diffuse sound field. The ICCCs in a reverberant field are not reproduced accurately using a conventional two-channel stereo-reproduction(More)
This paper investigates the significance of the magnitude or the phase in the short term Fourier spectrum for speech intelligibility as a function of the time-window length. For a wide range of window lengths (1/16-2048 ms), two hybrid signals were obtained by a cross-wise combination of the magnitude and phase spectra of speech and white noise. Speech(More)
This study investigates a signal theoretic approach to rendering acoustic events. Acoustic events modeling language (AEML) is an essential part of acoustic events rendering using an acoustic-data stream based on structured audio representation. This article mainly describes sinusoidal and envelope-modulation modeling for intelligible speech modification and(More)
This article describes a method of intelligible speech representation that uses narrow-band envelopes and their carriers. This method enables modification of the talker's voice pitch and speech-rate without sacrificing intelligibility. The carrier, which shows the instantaneous phase, conveys pitch information, while the temporal envelope conveys(More)
It was found that it was possible to reduce the number of samples needed for power measurements by sampling at the boundaries in a reverberation room. The space variances in the mean-square pressure of oblique wave fields in a rectangular reverberation room were calculated. The sound source was assumed to be a narrow-band noise source. Space variances(More)
Reverberation morphing from an impulse response is an inevitable 3D-audio technology as well as reverberation rendering for an immersive communication network. This paper proposes a method for reverberation morphing by relocating the poles and zeros of the transfer function. It assumes that the distance of the pole/zero locations from the unit circle in the(More)
An acoustic signal representation based on sinusoidal and envelope-modulation modeling is described. Such studies are crucial to acoustic events modeling for structured audio-signal representation and rendering through interactive networks. This paper confirmed that; (1) sinusoidal modeling is useful for constructing an intelligible speech using only a few(More)
This paper presents an approach to distinguishing the zeros representing a sound source from those representing the transfer function on the basis of Lyon's residue-sign model. In machinery noise diagnostics, the source signature must be separated from observation records under reverberant path conditions. In numerical examples and an experimental(More)