universal Nature. It sounds like a sensation of opening and enlarging of this passage.Sri Aurobindo
Letters of Sri Aurobindo
5. Planes and Parts of the Being
Fragment ID: 562
It cannot be anything physical but only a subtle physical sensation. The ear is the passage of communion between the inner mind centre and the thought-forces or thought-waves of the universal Nature. It sounds like a sensation of opening and enlarging of this passage.