声波和正弦波

一些木管乐器（比如管风琴，单簧管）生成泛音的频率比较的独特，只会生成奇数倍的泛音，也就是说，如果基音的频率是 $f$，那么它们生成的泛音频率将会是 $3f, 5f, 7f, \cdots$。

采样定理

傅里叶分析允许我们利用一系列的正弦波来表示一个周期的波形，其中的正弦波是某个基因的泛音。

采样定理告诉我们，若某有限带宽的波形可以用 $B$ Hz 表示，那么理论上可以以 $2B$ 的带宽来无错误的重建这个波形。例如，每秒对振幅 20000 的采样，可以准确的描述带宽为 10000 Hz 的波形。

时空中的听觉

Imagine stepping down from the porch of your country home on a moonless autumn night. A breeze stirs the remaining leaves of the maple tree above you. Disturbed by your footfalls, some tiny creature rustles in the leaves on the ground. In the distance you hear a car, and from the sounds it makes, you judge that it is not a new car. It turns in at your driveway. You can’t really see it you are blinded by the glare of the headlights but you hear the crunch of the gravel as it approaches. The car pulls to a stop. You hear the door open. “Hi, John,” a voice says. “Hi, Mark,” you reply. “Long time, no see.”

鸡尾酒会效应：人的听力选择能力，可以在一个嘈杂的环境中注意到自己想要的信息，而自动屏蔽无关的噪声。

优先效应：人耳可以判断直接听到的声音和回声。

参考文献

1. Perry R. Cook- 《Music, Cognition, and Computerized Sound》