The Power of Sound
"We may now consider the type of mantra which works only by its sound. The vibration which the sound sets in motion impinges upon the various bodies of man, and tends to bring them into harmony with it. A sound in the first place is an undulation in the air, and every musical sound has a number of overtones which it sets in motion as well. Four or five or more overtones are detected and recognized in music, but the oscillations extend a great deal further than the ear can follow. Corresponding waves are set up in higher and finer matter altogether, and therefore the chanting of a note or a series of notes produces effects upon the higher vehicles. There are sounds (I suppose we must still call them sounds) overtones which are too fine to affect the air; nevertheless they set etheric matter in motion, and that etheric matter communicates its oscillations to the man who recites the mantra and also to other people around him, and if he is directing his will towards any particular person, to that person the vibration will assuredly go. Thus the mantras which work by sound may produce decidedly material results on the physical plane, though there are other and finer waves sent forth at the same time which may affect the higher vehicles." [C.W. Leadbeater, "The Masters and the Path"]
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