What represents music in nature?

Sounds are closely related to the physical material and do not exist in the sense in which we know sounds in the more rarefied atmospheres of the spiritual worlds above that of the first spiritual zone.

All spiritual zones above the first are filled with an eternal silence, in a physical sense. Yet in these zones, there are sounds and continuous melodies and the sweetest music, but not attuned to the physical ear, nor to the ear that has not attained to the spiritual refinement of the sphere in which the sounds exist.

In fact, there are sounds and melodies in the physical material worlds that are not attuned to the physical ear and are heard only by the spirits of the first spiritual zone, and occasionally by someone in human form who spiritually is highly developed.

All Nature is attuned to music and each separate thing in Nature has its own melody, which it prefers to render. 

Silence is merely sound that has reached a spiritual refinement—sound that is not heard except by a life of the same vibratory refinement, as that of the sound that is heard through the silence—through that which to all others is silence.

Fragments of Spiritual Knowledge Pertaining to the Spiritual World