The term 'light' and 'sound' alone has an overly mystical/mythic ring to it. In addition, these terms are too contradictory. Contrary to those terms, the expression mirroring is often used in psychoanalysis and describes earliest identifications (as in: seeing oneself as being identical to, or knowing oneself as being identical to), and may be considered a consequence of the unconscious scopic-drive). Repetitive effects of the echo are also found in major psychoanalytic contexts of compulsions to repeat1 (a consequence of the drive to dispose of, to invocate, and to speak).
Subsequently, in psychoanalysis we assign a second life to the human being by earliest identifications (mirroring) and repetitive compulsions and theorize these two aspects in a dualism of 'powers', drives, i.e. the Freudian Eros-and Death-Instict or in Lacanian terminology the urges to look, or speak,. Analogous to this, Kirpal Singh speaks of 'light' and 'sound' as of extroverted primal principles, primal forces, primal powers of God ('God-into-expression-powers') thus, putting this duality under the roof of comparative religious teachings.2 In doing this, he slightly soothes rough mysticism, nor does he need to submit to a restricted religious denomination. However, yoga and psychoanalysis do have highly similar aims, though their ways may vary.
Kirpal Singh regards God as being a very real, though simultaneously also absolutely splitted being, who can only be recognized in these two alienated primal principles. God, the Absolute, the Metaphysics, is projected, comes to being solely in the form of those two attributes.3 There is no personal, nor in any way graspable, God - only the two primal powers or primal principles have come to exist.
1 This is to be understood as an unconscious and mostly unaware obsessive repetition of behavior, affects and thoughts which lastly deal with the process of symbolization
2 Such and similar denotations are found in almost all Yoga systems.
3 Singh, Kirpal, Die Krone des Lebens (The Crown of Life), H. E. Günther Verlag (1974), pages 158-162. At the same time, Kirpal Singh proves, that this applies to all religions. Also, in monotheism, God has segregated himself from his negative part (Satan).