And interesting area to research. Music sound tone therapy for healing.
Are you depressed? Perhaps try this spirit harmonics by numbers tone.
“The Seraphim are the highest order of angels, serving as the caretakers of God’s throne and continuously singing his praises. It is said that they surround the throne of God, singing the music of the spheres and regulating the movement of the heavens as it emanates from God.” http://www.answers.com/topic/hierarchy-of-angels