I own a Yamaha alto sax, but whenever I try to play a high 'D' on it i get a very high pitched, horrible sound. Is there any way to stop this?

try pushing your mouth tighter on the reed but not too tight. Same as doing a lower d loosen your grip. hope this helps if so visit my posts.

allycheekymonkey

Pull your mouthpiece off of your saxophone, and play it. Using a tuner or check with another instrument, what note are you playing in concert pitch? Please send me back what note you are playing with the mouthpiece alone.

I will see if I can help you with this.

Later
CJ