Hi,
You are being very optimistic in expecting the tone function to reproduce the sound of a saxophone or any instrument at all.
I would suggest that you adjust your expectations/project goals to 'have a saxophone style interface to an interesting sounding electronic instrument'.
If you really want to try reproducing a saxophone sound, you have a lot of reading ahead of you, there is a good series fo about 50 articles buried somewhere on this site - http://www.soundonsound.com/
If you want to go for the more realistic option of saxophone style interface to interesting electronic instrument, I suggest you look up the Auduino project, its not mine but I have collected some interesting examples here -
It could really benefit from a more instrument like user interface so could be the perfect marriage of two projects
Duane B