How many keys does a piano have?
Why 88 keys, not one more, not one less?
Could we have 8-octave pianos? In this article, we will cover the beginnings of the piano and the reasons why its development ended in 88 keys.
To begin, we must take into account the range of sounds that the human ear perceives: frequencies between 20 Hz the lowest pitch; at 20 kHz, the highest tone.
The first pianos appear around the year 1700, built by Bartolomeo Cristofori, being called "gravicembalo with piano e forte". In practice, it was like a key, but it had hammers instead of plectrums, and the mechanism was somewhat different. The news of this - a novel at that time - the instrument was spread among various instrument makers and musicians of the time such as Marquis Scipione Maffei, or Francesco Manucci, who talked about how this new invention allowed to play the piano and the fort.
Bach met some of Cristofori's pianos in the 1730s. However, this contact was not direct, but through Gottfried Silbermann's pianos, who made copies of the Cristofori with the addition of the resonance pedal.
It may be curious that Bach didn't really like this new instrument very much, that the upper octaves didn't sound too much. Later, Silbermann made some modifications in 1747, and it was then that Bach gave him his approval. .
Between the years 1760 and 1830, during the Industrial Revolution, the manufacture of pianos had significant expansion and underwent considerable modifications. The new and improved handling of steel and iron enabled some of these changes; such as the high quality of string steel, (correctly called a piano string) as well as the precision of cast iron. All of this was a response to the desire of composers and pianists to have a piano with a more robust and sustained sound.
Other instruments also suffered significant consequences from this revolution; for example, the harp began to be made of iron and the strings of steel.
Over time, the tonal range of the piano also increased, going from five octaves in Mozart's time to seven-eighths and a third or more of modern pianos, which we will cover in the next paragraph.
The pinnacle of piano-making took place in the late 18th century, around 1780, with manufacturers such as Johann Andreas Stein, Nannette Streicher, and Anton Walter. In 1828, Bösendorfer was founded in Austria, and in 1853 the German Heinrich E. Steinweg emigrated to the United States, where he founded the Steinway & Sons brand; which was a milestone in the development of pianos.
If the 88-key stabilization date - according to various historical sources - can be set between 1870 and 1890, this would mean that many classical composers such as Mozart, Beethoven, Haydn, even Chopin did not know of the stabilized version of the 88-key piano.
Having covered part of the piano's invention history itself, let's see why they couldn't have many more than 88 keys.
Inside the piano, the ends opposite the keys reach the sound production mechanism with a slight bias, which is usually the same on all pianos. The placement of these crossed strings requires the construction of blocks of notes where the sum is longer than the width of the keyboard itself.
On the other hand, in the organ and the harmonium, the tails of the keys are all of the equal widths. So, the space that the 88 keys occupy is not equivalent to the area that they hold inside the soundboard. If we add more keys, we may end up modifying the soundboard.
There are indeed some experimental pianos of the Bosendorfer brand (model 290, imperial) of 8 octaves in the tonal range. This idea arose from the director and pianist Ferruccio Busoni, who transcribed Bach's works for organ and found that the 16 and 32-inch organ pipes required additional bass notes. Bartok, Ravel and Debussy were some composers who wrote for this instrument, the organ, since it consisted of great resonance in the bass and supported a full projection of all frequencies.