Piano Soundboard Cracks

Posted on August 18th, 2014

Piano Soundboard Cracks, Piano Soundboard Pressure Ridges, the difference.

We at Manila Pianos Inc. are specialist in high quality used pianos, therefore we see a lot of soundboard problems and here are some observations for you. A soundboard of any piano has a vast amount of pressure exerted on it. Pianos will develop cracks after prolonged dry conditions.

New pianos, because of new wood, will crack much sooner than older ones, sometimes even within a week after being exposed to very dry conditions. More humid conditions cause sound boards to swell, pushing the wood grain with force causing the soundboard sometimes to develop a “pressure ridge”. Pic shows crack in the sound board. DO NOT BUY! It needs many hours and lots of money to fix this.

soundboard crack pic

When purchasing a piano check as much of the soundboard as you can see carefully for cracks. A crack is only going to get bigger and could affect the tone and overall sound of the instrument. If there is a distinct buzz when notes are struck quite firmly, this can also be an indication of a cracked soundboard. Although cracks can be repaired, it is a major job for a skilled piano technician, and would normally take several weeks in a workshop to complete at high cost.

Pressure ridges are not cracks but actually the opposite and I consider them good. Piano manufacturers will not guarantee a pressure ridge, they can be found even on many new pianos still sitting on the dealer’s showroom floor.

Everything in a good piano is either made of wood or depends on wooden parts to function. Wet, humid conditions swell and warps wooden parts and dry parched conditions shrinks and cracks wooden piano parts. (except new Kawai and Mason & Hamlin, they use plastic)

High humidity is bad for a piano and low humidity is even worse for a piano, and the worst is this swinging back and forth.Temperature and humidity control are therefor critical elements in maintaining a valuable instrument.

Wood is hygroscopic and it expands and contracts across the grain with agressive changes in humidity. The pitch of the strings depends to a certain extent on the amount of humidity present in the soundboard, which expands and contracts with changes in heat and relative humidity. If the environment is too dry, the soundboard will shrink beyond the dryness level at which the instrument was manufactured, causing cracks in the wood and even failure of glue joints.

Extreme dryness can cause complete failure of the soundboard and pin block. The loss of natural moisture in the soundboard also causes the pitch to go flat.

Too much moisture can ruin not only the soundboard but it also causes the wood in the keys to swell, resulting in sticking keys and sluggish response in the mechanism.

Excessive moisture may also cause the strings, tuning pins and other metal parts to rust.

For whatever reason I see more Yamaha grand pianos with pressure ridges than Kawai, I don’t know why, it’s possibly different spruce, but it’s just an observation from being in the business for a long time.

Conclusion: When purchasing a (grand) piano don’t buy one with a cracked soundboard, a pressure ridge or 2 is all right. After purchase, make sure you protect your instrument by keeping humidity levels between 35 and 65% and you should be ok.