Sound is the property of Akasha (ll-i-27),
It is perceptible by the ear (Il-ii- 21). It is momentary; and counteracted by its effect., by its cause and by both. It is produced by Conjunction, Disjunction, and another sound; It has a limited existence; and is brought about by homogeneous and heterogeneous causes. (ll-ii-25-32),
It is of two kinds (1) in the form of letters and (3) in the form of noise in general.
The former is in the shape of ‘a’ and other letters, and the latter in the shape of the noise produced by the blowing of the conch and such things,
Sound of the former kind proceeds from the contact of the mind and soul as influenced by remembrance :—First of all there is desire for pronouncing the letter ; this is followed by an effort on the part of the speaker ; and when this effort brings about the conjunction of the soul with air, there is produced in this air a certain action (motion) ; this air moving upwards strikes such places as the throat and the like ; this contact of the ‘place’ and the air brings about contact of the ‘place’ with Akasha and this contact produces the letter-sound.
८.२४: २८८.२अवर्णलक्षणोऽपिभेरीदण्डसम्योगापेक्षाद्भेर्याकाशसम्योगादुत्पद्यते ।
Sounds of other kinds also are produced by the contact of Akasha with such substances as the drum and the like. This contact being brought about by the contact of the drum and the stick.
Then again sound is produced by such Disjunctions as the splitting of the joints of the bamboo and that of Akasha and the bamboo; and also, from other sounds that may have been previously produced by certain conjunctions and disjunctions.
Sound is always produced in a series, like the series of water-ripples; and when sound, appearing in the form of waves, reaches the ear, it becomes perceived. As the Ear is not found to go to the sound [where it is produced), and the sound is not found, to have actually come to the Ear, and as there could he no perception of sound by the Ear, unless there were some sort of an approach of the one by the other —one cannot but accept the fact of sound being produced in the form a line or series of waves.