◊      That the svars are the shining, pure phonemes is further confirmed by Brihadāranyaka Upanishad I.3.26 :-

tasya   ha+etasya   sāmnah suvarnam veda bhavati
ha+asya   suvarnam tasya vai svar eva suvarnam
bhavati   ha+asya   suvarnam ya evam+etat+sāmnah
suvarnam veda .

 He who knows that this Sāman, lyrical speech, is like gold obtains gold. For, indeed those svars, vowels or pure sounds are    su + varna, also the word for gold. This is the Veda, or knowledge of the gold-nature of the Sāman.

Thus here the shruti equates svar, vowels or musical tones to su + varna, pure sound and hence derives suvarna, the word for ‘shining gold’ !

â, î, û (A¸ [ ¸ ]) – the pure vowels

◊       Now, â, î, û (A¸ [ ¸ ]) are the pure vowels. They are pronounced as follows :-

• â ( A ) is uttered from the expanded throat using samvrt prayatna or a contracted effort.[17]
• î ( [ ) is uttered from tālau jihvāmadhaym ivarne [18] or ‘the roof of the mouth above the tongue-middle’. It is palatal.
• û ( ] ) is uttered ‘by narrowing and rounding of the lips’.[19]

These three are spoken by just pushing the prāna or life-breath and the tongue is not moved but only positioned. The moment the tongue moves, as in speaking most of the other letters, the breath is reflected by it.