Found in Steinway pianos constructed 1936 and later, the patented diaphragmatic soundboard is not only made from the finest sitka spruce found on Earth, it is uniquely tapered outward from the center in a pattern that maximizes freedom of vibration. Additionally, it is double-crowned, bending in two directions simultaneously, creating a bell-like shape or diaphragm that projects the Steinway tone like no other piano.