Holophonic speaker system with filters that are pre-configured based on acoustic transfer functions

摘要

Disclosed is a surround sound system configured to reproduce a holographic spatial sound field in a sound control region (11) within a room having at least one sound reflective surface. The system is comprised of multiple steerable loudspeakers (12) located about the sound control region (11), a control unit (14) connected to each of the loudspeakers (12) and a sound field recording system comprising a microphone array (20) located in the sound control region (11). Each loudspeaker (12) has a plurality of speaker input signals (13). Each speaker input signal (13) controls one of a plurality of different individual directional beam response patterns which may be generated by the loudspeaker (12). The overall directional response of the sound waves emanating from the loudspeaker (12) is that created by a combination of the individual directional beam response patterns as dictated by the speaker input signals (13). In a playback mode the control unit (14) receives input spatial audio signals (16) representing the holographic spatial sound field for reproduction in the sound control region (11). The control unit (14) has pre-configured filters for filtering the input spatial audio signals to generate the speaker input signals (13) for driving the loudspeakers (12) to generate sound waves with respective overall directional responses that are co-ordinated to combine together at the sound control region (11) to reproduce the holographic spatial sound field. The holographic sound field is formed from the combination of direct sound emanating into the sound control region (11) directly from one or more loudspeakers (12) and reflected sound emanating into the sound control region (11) from the reflective surface(s) of the room. The filters of the control unit (14) are pre-configured in a configuration mode prior to operating in the playback mode based on acoustic transfer function data. The acoustic transfer function data is measured by the sound field recording system. The acoustic transfer function data represents the acoustic transfer functions measured by the microphone array (20) in response to test signals (22) generated by each of the loudspeakers (12) for each of their individual directional beam response patterns at their respective locations in the room.