Okay, so I was listening to someone via tinychat explaining how our current understanding of sound was wrong in some sense. He claimed that the source of the propagation of sound waves HAD to be moving faster than the speed of sound (in air). One particular analogy he used in order to explain his argument is that the frequency of a rope was directly dependent on the motion of your fist moving the rope in a wave-like manner (which is true). Yet, he extended this analogy with the snap of your finger, in that the interactions between your thumb and ring finger moved faster than the speed of sound in order to produce the sound in the air. Well in air, sound waves 'travel' ~340.2 m/s or something like that... I had a problem with his claim, because I could slam my fist very slowly against a table much slower than the actual speed of sound, and still produce waves through the air. He kept claiming that every source producing these waves had to make a sonic boom, because it dictates the frequencies of energy propagated. I'm not a physicists, but should this claim be taken seriously? Or simply ignored? Thanks for your time.