I never stated anything about sound, that was the others and their Brown noise bunk.
I would have thought that you knew what I meant and that I wasn't suggesting that the sound did anything, further more, that I am aware that "sound" is only relevant when vibrations cause the bones of the inner ear etc to convert the vibrations to electrical impulses, which in turn, are interpreted by the brain.
So yes, clearly, I am fully aware that a deaf girl, could be equally impressed by a guy humming on her bits
Motorcycle (something large, throbbing between their legs), or washing machine on spin
Stimulator wise, contact only makes the effect easier to achieve, with less effort. Obviously, to hold said stimulator near, but not touching the body, would have little effect than to annoy the neighbours, but...speakers, with sufficient power, will be able to apply the effect of each cone excursion, to the air and this air movement and
pressure change, will have a similar effect.