Express Paper
Open Access
Generate acoustic responses of virtual microphone arrays from a single set of measured FOA responses. - Apply to multiple sound sources.
Express Paper · Paper 299 · September 2024
Abstract
We propose a method, V2MA, that virtually generates acoustic responses of any type of microphone array from a single set of FOA responses measured in a target room. An A-format microphone is used for the measurement, but no Ambisonics operation is included in the processing. V2MA is a method based on geometrical acoustics. From a measured FOA response, we calculate instantaneous active sound intensities in the x, y, and z directions, then acoustic information about the virtual sound sources, i.e., the dominant reflections, of the room are detected from them. Although it is desirable to have an A-format microphone place close to the attempted position of the virtual microphone array in the room, it is not a mandatory requirement. Since our method allows to generate SRIRs, spatial room impulse responses, at arbitrary receiver positions in the room by updating the acoustic properties of the virtual sound sources detected at a certain position of the room, an A-format microphone can be placed anywhere you like such as at the one of audience seats. On the other hand, a loudspeaker has to be placed at the source position where a player is assumed to be when virtual recording. Since the positions of virtual sound sources change when a real sound source moves, we need to store a set of virtual sound source data for each assumed real source position. For example, we are required to measure four sets of FOA responses by placing a loudspeaker at four positions, if we would like to generate V2MA responses for a quartet performance. To improve this inconvenient restriction, we developed the technique of updating the positions of the virtual sound sources when a real sound source moves from its original position. Although the technique requires some approximations, it is ascertained that the generated SRIRs provide fine acoustic properties in both physical and auditory aspects.
