“In conclusion, VA therapy influences both psychological and physiological
processes. Music is received, processed and interpreted in the brain, and the
emotional and associating effect of music stimulates psychological processes. At
the same time, physical effects go alongside or are the result of psychological
activity, and music has an active effect on physical behaviour. These experiments
have not only identified further evidence of the way music affects us at a
psychological level, but has also measured physical response. Because VA therapy
is an intervention that presents a physical stimulus in the form of a pulsed sinusoidal low frequency tone, these studies have found some evidence of the effect of sound within this frequency range”
https://www.wfmt.info/Musictherapyworld/modules/archive/stuff/papers/Wigram.pdf