Patent ID: 8503682

Claim:
A head-related transfer function convolution method arranged, when an audio signal is reproduced acoustically by electro-acoustic conversion means disposed in a nearby position of both ears of a listener, to convolute a head-related transfer function into said audio signal, which allows the listener to listen to the audio signal such that a sound image is localized in a perceived virtual sound image localization position, said head-related transfer function convolution method comprising: measuring, when a sound source is disposed in said virtual sound image localization position, and sound-collecting means are disposed in the position of said electro-acoustic conversion means, a direct wave direction head-related transfer function regarding a direction of a direct wave from said sound source to said sound-collecting means, and a reflected wave direction head-related transfer function regarding a direction of selected one reflected wave or reflected wave direction head-related transfer functions regarding the directions of selected plurality of reflected waves, from said sound source to said sound-collecting means, to obtain the direct wave direction head-related transfer function, and the reflected wave direction head-related transfer function or the reflected wave direction head-related transfer functions, separately beforehand; and convoluting said obtained direct wave direction head-related transfer function, and said reflected wave direction head-related transfer function regarding the direction of said selected one reflected wave or said reflected wave direction head-related transfer functions regarding the directions of said selected plurality of reflected waves, into said audio signal; the measuring comprising: first measuring, including: placing acousto-electric conversion means nearby both ears of the listener where placement of electro-acoustic conversion means is assumed, picking up first sound waves emitted at a perceived sound source position with said acousto-electric conversion means in a state where a dummy head or a human exists at said listener position, and measuring the head-related transfer function from only the first sound waves directly reaching said acousto-electric conversion means; and second measuring, including: picking up second sound waves emitted at the perceived sound source position with said acousto-electric conversion means in a state where no dummy head or human exists at said listener position, and measuring a natural-state transfer property from only the second sound waves directly reaching said acousto-electric conversion means; normalizing said head-related transfer function measured by said first measuring with said natural-state transfer property measured by said second measuring to obtain a normalized head-related transfer function; and storing the normalized head-related transfer function obtained in said normalizing in a storage unit.