The hunt for the wood used for the soundboard begins in the forest. Experts look for trees with specific acoustic properties and are harvested only when a tree is ‘ready’. Foresters are specially trained to know the 'signs' that indicate when a tree is ready! For uninitiated observers, one tree will look pretty much the same as any other, but these guys know the appropriate time to fell the tree.
Manufacturers like to keep their methods to themselves. Some believe their designs, specifications and particular construction features give their pianos a unique sound and tone, and so are keen to protect their ideas from being copied.
Glued to the sound-board is a wooden ‘bridge’. This is the all-important link between the strings and the soundboard. Every string passes over the bridge and is kept firmly in position by locating 'bridge-pins'. These define one end of the ‘speaking-length’ of the string. The metal frame is fitted - attached around the edges of the soundboard, leaving the soundboard to vibrate freely.
The frame provides the strength needed to withstand the sheer tension across the 7 and a quarter octaves of strings! Each string travels from the tuning-pin, through an agraffe or over what defines the beginning of the speaking length of the string, across the central part of the soundboard, to the 'bridge' (the end of the speaking length) and finally to the hitch-pin anchored in the metal frame.
The soundboard is slightly convex in shape. This and the tension of the strings when tuned, produces a sensitive and highly charged unit at the core of the piano.
The action and the keyboard - dealt with in another post here, are the mechanical link between the pianist and the sounds created by the vibrating strings.
The Piano World
© Steve Burden