Srimad Bhagavatam Canto 03, Chapter 12, Text 47

SB 3.12.47

sparsas tasyabhavaj jivah
 svaro deha udahrta
usmanam indriyany ahur
 antah-stha balam atmanah
svarah sapta viharena
 bhavanti sma prajapateh
 
Translation by His Divine Grace A. C. Bhaktivedanta Swami Srila Prabhupada: 
 
Brahma’s soul was manifested as the touch alphabets, his body as the vowels, his senses as the sibilant alphabets, his strength as the intermediate alphabets and his sensual activities as the seven notes of music.
 
Purport by His Divine Grace A. C. Bhaktivedanta Swami Srila Prabhupada: 
 
In Sanskrit there are thirteen vowels and thirty-five consonants. The vowels are a, a, i, i, u, u, r, r, l, e, ai, o, au, and the consonants are ka, kha, ga, gha, etc. Amongst the consonants, the first twenty-five letters are called the sparsas. There are also four antah-sthas. Of the usmas there are three s’s, called talavya, murdhanya and dantya. The musical notes are sa, r, ga, ma, dha, and ni. All these sound vibrations are originally called sabda-brahma, or spiritual sound. It is said, therefore, that Brahma was created in the Maha-kalpa as the incarnation of spiritual sound. The Vedas are spiritual sound, and therefore there is no need of material interpretation for the sound vibration of the Vedic literature. The Vedas should be vibrated as they are, although they are symbolically represented with letters which are known to us materially. In the ultimate issue there is nothing material because everything has its origin in the spiritual world. The material manifestation is therefore called illusion in the proper sense of the term. For those who are realized souls there is nothing but spirit.
Srimad Bhagavatam Canto 03, Chapter 12, Text 46
Srimad Bhagavatam Canto 03, Chapter 12, Text 48