AMSR is a repetitive, relaxing sound. It can be different for different people. As the site at the link below says, AMSR is a “...relaxing, static-like, sensory phenomenon” Its designer to invoke a tingly sensation that goes from your scalp and down your spine... which provides a sense of euphoria. There are lots of online options to experience this.
Benefits include
Reduce heart rate and a sense of relaxation such as from a massage.