in Vibroacoustic Therapy (VAT) sound is transferred to skin surface via transducers that are in direct contact with the skin. This means no energy loss to surrounding air. We are mostly using sinusoidal frequences between 30 Hz and 120 Hz. The different organs inside the body are of different density and the sound waves will therefore bounce in different directions and be differently absorbed by the internal organs. We know, empirically, that the effect of the internal sound massage usually is positive , relaxing and stimulating. as the density of different organs are different, sounds will be differently absorbed or penetrating different tissues. Have anyone done research how single cells and their internal structure are reacting to sounds? As acoustics describe auditively perceived sounds, the "endoacoustic" effects must be described by a totally different vocabulary, because we are looking for the medical effects of surface-to-surface transfer of phonons to the human body. Do anyone have ideas of how we can describe the effect of VAT.
sound waves of that low frequency will not be affected by the position or density or size of the internal organs. for organs to be targeted, the wavelength of the sound must be smaller than the dimensions of the organ. Note also that individual cells in the body that make up those organs are extremely small compared to your wavelengths and so they individually experience only extremely tiny effects when low frequency sound passes through them. those effects would be nearly impossible to measure.
Regarding phonons: the phonon concept only makes sense when describing the response of a crystalline solid to wavelengths of sound that are of similar order to the spacing between individual crystallites, or smaller. It's important on scale lengths where quantum effects become important and not when describing sound wave propagation through macroscopic bodies of varying composition.