What frequency to use to regenerate brain cells?

as you can see from the above response

you posted this question on the wrong site

unfortunately the scientific community insists on empirical evidence

which is actually based on statistics

i know a little bit about this because i'm at ucla doing research

but i'm also open minded enough to see its faults

and a large portion of this particular community are unbending

i'm not familiar with this type of therapy

but if you go to wikipedia's article on "cranial nerves" V, VII, IX, and XII

then look up Broca's area and Wernicke's area

then if the sound is the most salient aspect of the tuning fork check CN VIII

and if the vibration is the most salient aspect:

Ruffini's end organs detect tension deep in the skin.

Meissner's corpuscles detect changes in texture (vibrations around 50 Hz) and adapt rapidly.

Pacinian corpuscles detect rapid vibrations (about 200–300 Hz).

Merkel's discs detect sustained touch and pressure.

Mechanoreceiving free nerve endings detect touch, pressure and stretching

Hair follicle receptors are located in hair follicles and sense position changes of hairs.

Pshh... why don't you implement a therapy routine that actually has scientific backing for its success. I'd be pissed if I was one of your patients.