ABSTRACT
Observe that, because f appears in the denominator, low frequencies disperse more widely than do high ones. A numerical example is useful. For this we supposeD = lOW and c = 344 m/s:
As one can see, the effect is substantial. The low frequencies really do disperse far more than do the high ones, which are virtually focused. This has an obvious differential effect on complex sounds, such as speech. Only the low frequencies of speech spread through a door. Section VI. 7.1 establishes that the loss of high frequencies does not greatly affect the intelligibility of speech.
