<P> In all but the lowest quality pianos the soundboard is made of solid spruce (that is, spruce boards glued together along the side grain). Spruce's high ratio of strength to weight minimizes acoustic impedance while offering strength sufficient to withstand the downward force of the strings . The best piano makers use quarter - sawn, defect - free spruce of close annular grain, carefully seasoning it over a long period before fabricating the soundboards . This is the identical material that is used in quality acoustic guitar soundboards . Cheap pianos often have plywood soundboards . </P> <P> The design of the piano hammers requires having the hammer felt be soft enough so that it will not create loud, very high harmonics that a hard hammer will cause . The hammer must be lightweight enough to move swiftly when a key is pressed; yet at the same time, it must be strong enough so that it can hit strings hard when the player strikes the keys forcefully for fortissimo playing or sforzando accents . </P> <P> In the early years of piano construction, keys were commonly made from sugar pine . In the 2010s, they are usually made of spruce or basswood . Spruce is typically used in high - quality pianos . Black keys were traditionally made of ebony, and the white keys were covered with strips of ivory . However, since ivory - yielding species are now endangered and protected by treaty, or are illegal in some countries, makers use plastics almost exclusively . Also, ivory tends to chip more easily than plastic . Legal ivory can still be obtained in limited quantities . The Yamaha firm invented a plastic called Ivorite that they claim mimics the look and feel of ivory . It has since been imitated by other makers . </P> <P> Almost every modern piano has 52 white keys and 36 black keys for a total of 88 keys (seven octaves plus a minor third, from A to C). Many older pianos only have 85 keys (seven octaves from A to A). Some piano manufacturers have extended the range further in one or both directions . For example, the Imperial Bösendorfer has nine extra keys at the bass end, giving a total of 97 keys and an eight octave range . These extra keys are sometimes hidden under a small hinged lid that can cover the keys to prevent visual disorientation for pianists unfamiliar with the extra keys, or the colours of the extra white keys are reversed (black instead of white). More recently, manufacturer Stuart & Sons created a piano with 102 keys, going from C to F. The extra keys are the same as the other keys in appearance . </P>

What are the keys on a piano made of