USING THE SOUND GRID PRINCIPLE TO REVEAL THE PHENOMENON OF PECULIAR MULTI-STEP MUSIC

The light intensity distribution formed by light waves through gratings is actually the result of single slit (groove) diffraction and multi-slot (groove) interference of grating. Observations have revealed that when a sufficient number of steps are exposed to incident noise of a certain intensity, a specific frequency band of musical sounds can be obtained in the reflected sound field. This paper, imitating a blazed grating, considers multiple steps as a plane reflective sound grating, i.e., a blazed sound grating, and provides the sound intensity distribution of the blazed sound grating, as well as the constraint relationship satisfied by the path difference of the reflected sound waves between adjacent grooves. At the same time, based on the measured data from field investigations and the corresponding frequency spectrum curves, the phenomenon of musical sounds formed in the reflected sound field of multiple steps is analyzed in conjunction with the principle of plane reflective sound gratings. Two phenomena, the “firecrackers under the monument echoing military bugles in the air” at the Mau Shan Anti-Japanese War Victory Memorial in Jiangsu, China, and the “calling cranes to return and resonate” at Heshan in Qingdao, Shandong, China, are used as examples to illustrate this.