Sounds like quackery to me. And improving one's sensitivity to higher pitches is a really bad idea. I'm sensitive to higher pitches than most people and it makes urban living agony -- old CRTs and badly maintained car brakes are like daggers in my hears.
Sounds like quackery to me. And improving one's sensitivity to higher pitches is a really bad idea. I'm sensitive to higher pitches than most people and it makes urban living agony -- old CRTs and badly maintained car brakes are like daggers in my hears.