Sometimes when you are astral travelling you may hear many strange noises.
Sometimes these are very loud bangs, high pitched whistles or even sonic booms.
Although it may disturb you the noises can do no harm.
Sometimes the noises make you jump back into your body.
People have often reported hearing a one note flute in a forest of wind.
Some other people report never hearing any noises and seem to travel in silence.
Astral Travel
Paralumun New Age Village