BUT accordion MAKERS can, and some accordians are made by Hohner which also makes the melodica. A dear old friend who can make darned high quality bandoneon-like sounds with a melodica found they are always sharp by a couple of Hertz. He inquired. Hohner does this ON PURPOSE! They explained to him that if you overblow it, it descends to concert A440. Since subtlety is his long suit, he was displeased, but Hohner would not help. So, if there is anyone but a string player to play with, he can't use it, because Hohner is selling them for use by non-musicians!