声源空间分离对向前时域掩蔽阈值的影响

从实验上探讨了掩蔽和被掩蔽声源在水平面方向分离时的向前掩蔽效应，并与单扬声器重发方式作比较．得到了这2种情况下3种频率的被掩蔽纯音信号（250Hz，1170Hz，4000Hz）的掩蔽闻值随掩蔽窄带噪声5种声压级（30dB，40dB，50dB，60dB，70dB）变化的曲线。实验结果表明：声源空间分离时，除了个别情况外，掩蔽阈值都比单扬声器重发时有较大幅度的降低。文中进一步指出掩蔽阈值的降低是较优耳效应和双耳效应等的综合作用造成的。因此掩蔽声和被掩蔽声在空间上的分离会削弱向前时域掩蔽的作用，这一结论可为将来改进音频压缩算法提供理论基础。

Effect of Spatial Separation in Azimuth on the Threshold of Forward Masking in Time Domain

In this experiment,forward masking effect was studied when the masking and masked sources are spatially separated in azimuth,and compared with single-loudspeaker reproduction condition. Thresholds for the detection of brief sinusoidal signals (250,1170 and 4000Hz) masked respectively by three narrowband noise forward maskers were measured as a function of masker level (30,40,50,60 and 70dB). For spatial separation condition,the thresholds tended to drop by a relative large amount,with only very few exceptions. The results were analyzed by the combination of better-ear contribution,binaural effect and etc. In general,it can be concluded that the spatial separation of masking and masked sources will weaken the effect of forward masking in time domain. This conclusion can serve as a theoretic basis for improving digital audio compression scheme.