This is the second in a series of three articles about the three piano structural elements that must be in good condition in order for a piano to hold a tuning. The three structures are the piano pin block, the piano soundboard, and the piano bridges. In the last article, your piano Tuner Wilmington DE discussed the pin block, and this article will discuss the piano soundboard.
Most people have heard of a piano soundboard. It is the large piece of wood below the piano strings that amplifies the volume of the sound emanating from the strings. Without it, a piano would sound about as loud as an electric guitar that is not turned on. There is a common belief that a cracked piano soundboard indicates that a piano worthless. However; while a cracked soundboard is not optimal, it usually does not mean that your piano is worthless.
Here is some background information about the piano soundboard: The soundboard is made from several pieces of Sitka spruce. These are about 3/8″ thick and glued at the sides to make a wide and very thin soundboard. It is formed into a dome or “crowned” shape using ribs running cross-wise to the grain of the soundboard. The dome is toward the strings. The piano strings are attached to the soundboard via the piano bridges. As a result of this attachment, there is a cumulative total pressure of 500 lbs. onto the soundboard. Spruce is a soft wood, so this is a relatively large stress on a relatively delicate structure. Changes in temperature and humidity cause the wood to expand and contract, stressing it further. If the wood is stressed beyond its capacity, it will crack.
A crack usually does not affect the piano’s ability to hold a tuning, and it will not decrease the soundboard’s ability to amplify sound. The one problem that could arise would be if the soundboard were to detach from the ribs at the site of the crack. If this occurs, then at some temperature and humidity ranges a vibration can occur between the soundboard and the ribs. If so, it would make a low-pitched sound like the piano is humming along with you as you play. This typically is only occasional and it can sometimes be reduced. The only permanent correction would be to re-attach the soundboard to the ribs.
Your Wilmington and Philadelphia piano tuning expert, Kenneth Keith Piano Services, can help you with an assessment of your piano’s conditions and/or any of your Philadelphia and Delaware piano tuning or piano service needs.