The frame in a piano must be able to withstand a total string tension in excess of twenty tons; not only does the frame work to support the string tension, but it has a profound effect on the instrument’s sound. Yamaha makes its own frames, relying on a method of casting referred to as “vacuum process,” the world’s first such technique developed over many years in creating some of the best piano frames. During this time we have built up a storehouse of knowledge on factors such as the manner in which controlling the temperature and composition of casting, and even the coating used on the frame itself, affects the acoustic characteristics of the piano. This is a major reason that Yamaha is able to ensure reliable quality when crafting our pianos.