During the next hundred years following Cristofori’s death, we have seen that the piano underwent a series of significant developments. Today’s pianos are magnificent instruments and in almost every sense dwarf their more unassuming ancestors. Take for instance a contemporary concert grand: it has an average weight of 480 kilograms, 9 feet in length, and reaches 3 feet tall.
Pianos are high precision instruments, with almost 1,000 working parts and make use of a wide variety of materials. The principal parts of the piano, specifically of the grand piano, are the following:
A key is essentially a lever, operating on the principle of a see-saw. When one end is pressed down, the other end comes up, sending a hinged hammer flying upwards (forward in the case of an upright) towards the string. The strength of the sound is determined by the speed of the hammer immediately preceding the moment of impact. At the same time, the key lifts the damper, enabling the string to vibrate freely. The keyboard of a standard grand piano has 88 keys. The keys are formerly made of ivory for white hammers and ebony and stained pear wood for black hammers. Now they are made out of plastic.
The hammers are that part which strikes the strings of the piano when the keys are pressed down. The hammers, which are made of mahogany, are originally covered with soft but resilient leather. The hammers of modern piano are generally covered with hardened felt of carefully graduated thickness throughout the instrument’s compass.
The escapement is the device which allows the hammer to fall back immediately after impact, enabling the string to continue vibrating even while the key remains depressed or the dampers raised. This ingenious mechanism was one of the most revolutionary features of Cristofori’s instrument. The double –escapement action, introduced by French maker Erard, between 1809 and 1823 enabled the rapid repetition of notes and paved the way for the present day action of the grand piano.
The dampers are pads of felt, mounted on wood, which prevents each string’s vibration except when lifted by the key or the sustaining pedal. Until John Broadwood invented the ‘sustaining pedal,’ the action of lifting the damper on early square pianos was achieved by means of hand-stop similar to that of an organ.
The strings of modern piano are made of high –tension steel and are apportioned at the rate of three strings per note except for the bass register. The bass strings are of steel, tightly wrapped in coiled copper. The pitch of a string depends on its length, diameter, and density of its metal, and the tension to which it is subjected. The tension of a single string today may reach as much as 200 lbs, and the strings of a modern concert grand, more than 30 tons.
Early pianos had a wooden frame. It was Alpheus Babcock who introduced the iron frame in 1825, which enabled the instrument to support the heavier strings required for a stronger, fuller tone. Thus Bobcock’s invention was considered as perhaps the single most significant development in the history of piano technology. Chickering, and finally, Steinway improved on Babcock’s frame.
All grand pianos have at least three pedals; all concert grands have three. Of these pedals the most important is the ‘sustaining pedal’, which keeps the dampers raised above the strings for as long as the pedal is held down. This device was introduced by John Broadwood and has often been called ‘the soul of the piano’.
The ‘soft’ pedal, also known as ‘una corda’, shifts the entire action (keyboard, hammers and all) to the right so that the hammers strike one less string than normally. The function of this pedal is not primarily to reduce the actual loudness of tone but to alter its quality.
The third pedal, known as ‘sostenuto’ pedal, is placed between the other two pedals. This pedal keeps the dampers lifted only over those notes whose controlling keys are depressed at the moment when the pedal is applied. Apart from a few works by the French ‘impressionists’ like Ravel and Debussy, this pedal is not required for the proper playing of the piano repertoire as a whole.
In stringed instruments, the sound is amplified by the sympathetic vibration of another surface, generally of wood. In the grand piano, the soundboard lies below the strings and is buttressed by a series of wooden bars glued to its underside. The size and deployment of these bars has a significant bearing on the overall sound of the instrument and partially accounts for the different “characters” of various pianos and national manufacturing.