虚拟听觉重放与听觉声源宽度的扩展

Virtual Auditory Replay and Broadening of Auditory Source Width

通过心理声学实验研究了用前方一对±45°、±60°、±75°、±90°虚拟扬声器重放不相关噪声信号,以及前方一对虚拟扬声器和真实中置扬声器同时重放不相关噪声信号时,听觉声源宽度(ASW)的扩展和均匀度.结果表明:仅用一对虚拟扬声器重放时,对中心频率为250Hz^1 kHz的倍频程噪声,ASW最宽可以扩展到±70°左右,对粉红噪声ASW最宽可以扩展到±50°左右;当一对虚拟扬声器的张角较宽时,声像扩展不均匀,出现中间空、两边强的现象;当采用虚拟扬声器和真实的中置扬声器同时重放时,中置扬声器相对于虚拟扬声器的重放声压级对ASW的宽度和均匀度都有较大的影响;通过调节中置扬声器的重放声压级可以使ASW均匀扩展到比较宽的位置.进一步的理论计算和实验测量表明:只有在IACC0(双耳信号互相关函数在t=0时的取值)>0的情况下,ASW和IACC(双耳信号互相关系数的最大值)之间才具有线性负相关性;而对所有类型的重放信号,ASW和IACC0之间都具有线性负相关性.

Psychoacoustic experiments are conducted to investigate the broadening and the evenness of auditory source width （ASW） when uncorrelated noise signals are reproduced by a pair of virtual loudspeakers respectively located at ±45°, ± 60°, ± 75° and ±90°, and by a pair of virtual loudspeakers and a real central loudspeaker simultaneously. Results show that： when signals are reproduced only by a pair of virtual loudspeakers, ASW can be broadened to a maximum value of about ± 70° for octave noises with a central frequency varying from 250 Hz to 1 kHz, but the maximum reaches about ±50° for pink noises. When the angle between two virtual loudspeakers is wide, ASW can not be evenly broadened and it becomes empty in middle and strong in sides. When a pair of virtual loudspeakers and a real central loudspeaker replay simultaneously, the sound pressure level of the central loudspeaker relative to virtual loudspeakers greatly affects the ASW and its evenness. ASW can be evenly broadened to a wide range by adjusting the sound pressure level of the central loudspeaker. Furthermore, theoretical calculation and test results show that there is a negative linearity between ASW and IACC （the maximum of inter-aural crosscorrelation function） only when IACC0 （the inter-aural cross-correlation value when r = 0） is greater than 0, whereas for all kinds of replay signals, the negative linearity always exists between ASW and IACC0.