|Are some frequencies of sound more directional than others and, if so, why? — BKZ, Dayton, OH
In open air, sound waves travel in straight lines regardless of frequency or wavelength. But low frequency (long wavelength) sounds don't fit well in confined spaces and have less directional character to them. That's why you only need one subwoofer for a sound system—you can't hear where the lowest frequency sounds are coming from any way. Higher frequency sounds remain relatively directional, even in confined spaces. The same effects apply to electromagnetic waves—in confined spaces, long wavelength radio waves are effectively less directional than short wavelength light waves.