Svadhisthana and the Modern Correspondence

Svadhisthana, the Sacral chakra, is described in classical Sanskrit tantric literature through its own seed syllable, its lotus petal count and colour, and its presiding deity, none of which reference Western musical pitch. The pairing of this chakra with the note D belongs entirely to the modern chakra-tone correspondence system that emerged from early twentieth century Theosophical writing and its later New Age elaboration, a system built by mapping an ascending Western musical scale onto the ascending sequence of chakras from base to crown rather than by any continuity with the older Sanskrit material.

Because the correspondence system treats the diatonic scale's second degree, D, as belonging to the second chakra in ascending order, the pairing is essentially positional and mnemonic rather than derived from any documented resonance or acoustic property specific to D itself; a different modern author choosing a different scale or a different note order could, and in some published alternative schemes has, produced a different pairing entirely.

Sources The Serpent PowerSir John Woodroffe (Arthur Avalon) with Rainbow Body: A History of the Western Chakra System from Blavatsky to BrennanKurt Leland