Psychically, advanced Yogic students, by virtue of a subjective mastery over the repetition of OM, release rhythmic internal vibrations and regulate the irregular flow of the vital force, the unsteady and disharmonious vibrations of the five sheaths, restore a rare poise and balance to the mental functions, and seek to hit the plexuses and awaken the powers coiled in them. Great seekers after Truth meditate upon it, for an assimilation of its deepest significance, and its most comprehensive meaning, which were, tradition has it, difficult of description, even for such great sages like Brihaspati and Vasishtha. The sacred Books of Truth-realization speak of OM in a series of metaphors such as a bow, an arrow, a ship that conveys the soul of man into the Bosom of the Eternal and the Infinite, which it itself is. The first manifestation of God is Ether or Sound. Sound is the quality of Ether.
Sounds are vibrations.
They give rise to definite forms. Each sound produces a form in the invisible world. Combinations of sound create complicated shapes. The text-books of science describe certain experiments which show that notes produced by certain instruments, trace out on a bed of sand, definite geometrical figures. It is thus demonstrated that rhythmical vibrations give rise to regular geometrical figures.