Alright, I have two options. I can upgrade the sound waves so that it will cause internal damage to organs and perhaps even rupture a few. But the thing is about this, you would have to be wearing a special type of ear coverage or something to prevent harming yourself. Or, I could physically modify the waves, making it so that the sound vibrations get directly compressed into a force which can be controlled and directed through the sax. These compressed vibrations could cause internal rupture and brain damage, but could also do physical damage like break bones or at least knock back. The drawback to this though, is that the vibration fields would have to be directed by you playing the sax, rather than just emitting indiscriminate sound waves that'll hurt all. I personally think that this option is better, because it's more versatile and flexible overall. Plus, I could edit it so that it emits waves of electricity combined with your sax's sound waves.