Most players know that reed instruments when played at their softest levels have the tendency to go sharp. Conversely when played at their loudest levels they have a tendency to go flat. To investigate and discuss why this phenomenon happens is the purpose of this thread.
Band directors have long had to deal with intonation issues in younger groups when they play outside of their comfort zone which is mf. Compounding the problem is the fact that the tendency of the flutes and brass instruments is the exact opposite of the reeds.
There you have it. Why does my sax and clarinet want to go sharp during a diminuendo and flat during a crescendo?