The first few days I had my Tyros 5 I was hearing high buzzing noises. I immediately thought it was caused from the Tyros 5. Further investigation showed my tower speaker cabinets had become unglued in a few places causing them to vibrate and make that noise. It wasn't until I was playing the Tyros 5's Tutti Concert Organ at a high volume that this noise was noticeable. I guess I never played Tyros 4 that loud!! -charley