From the permutations of Sri Yantra and the pentagon, especially in their primary relations to circle and square, we can derive the actual proportional series that govern the relationship of the notes with the musical scales (ragas nd raginis) and the derivation of the secondary raginis from the primary ragas. This is the secret of Sri Yantra with its corresponding mantras.
Yantra and the musical modes of the raga system are inherently related through their mathematically-proportioned foundation. Just as the basic notes of each raga are harmonised so are the visible lines in each yantra. And just as the musical string must be plucked in a particular fashion to sound a certain note, so must the yantra line be mastered and mentally plucked to bring forth its image or power. Thus, the yantra diagram of apparently static lines will, with mental application, vibrate in perfect relation like a finely tuned musical instrument.