According to Osho, inner sound (nada) is authentic only when it arises spontaneously; repetition of AUM may evoke imagined sounds. When nada begins, the proper practice is detached witnessing—do not merge into it, or you will stall before the seventh plane. Keep refining awareness as the sounds grow subtler, observing unwaveringly until the nada dissolves into complete silence.
Don’t force inner sounds by chanting; let them come naturally and quietly watch them until they fade into silence.