The quote above is from a radio show I heard this evening, driving home, and it’s from a neurologist who points out that sound does in fact arise from air waves touching the small bones of the ear, and eventually being translated into electrical current; according to current research, electrical currents that are rhythmic produce pleasant sensations, while those that are chaotic make us uncomfortable.
More at the level of meaning, the same neurologist noticed that when parents who have been holding their babies put them down, they tend to immediately start talking to them, using verbal melodies that for certain basic messages (“Good baby!” “Watch out!”) are universal across cultures. The implication was that sound can actually be a substitute for touch, or put differently, that sound is a form of touching.
 I happen to be working with sound as a sense modality in some teaching I’m doing at the Nyingma Institute, so this was all quite interesting to me. I won’t go into details; let me just say that we do ourselves a disservice if we think we know what it is like to sense something. Our senses seem to be much more malleable than we imagine. And this is something to explore not only in specific exercises (TSK exercises, meditation practices, etc.), but in our walking-around daily activities.