A historical overview
The modern piano, with its 88 keys, is a culmination of centuries of evolution in sound systems, mechanical design, and musical theory.
This instrument represents the complex history of musical scales, tuning systems, and technological innovations.
To understand its development, we must explore its origins, the changes in sound systems and mechanics, the significance of the 12-note chromatic scale, and the decisions regarding the inclusion or exclusion of microtones.
Origins and early keyboard instruments
The development of the piano begins with early keyboard instruments such as the clavichord and harpsichord in the 14th and 15th centuries.
These instruments featured a simple mechanism: when a key was pressed, a string was either struck (in the clavichord) or plucked (in the harpsichord).
While these instruments allowed for different pitches through their keyboards, they did not offer the dynamic range and expressive capabilities of the modern piano.
Clavichord:
This instrument allowed for some dynamic control (softness and loudness) by varying the pressure on the keys, but the sound was relatively soft and not suitable for large venues.
Harpsichord:
Offered a louder sound suitable for public performances but lacked dynamic control, as the plucking mechanism produced a uniform volume regardless of how the keys were pressed.
During this period, Western music was evolving from the modal systems of medieval and Renaissance music toward a system based on tonality, with the major and minor scales becoming the primary basis for composition.
The 12-note chromatic scale, based on subdividing the octave into 12 semitones, gradually became the foundation of Western music.
The invention of the pianoforte
The piano as we know it began with the invention of the pianoforte (literally "soft-loud") by Bartolomeo Cristofori around 1700 in Florence, Italy.
Cristofori was a harpsichord maker who sought to create an instrument that combined the best qualities of both the clavichord and the harpsichord: the ability to play both soft and loud notes (hence "piano" for soft, "forte" for loud).
Cristofori's pianoforte introduced several crucial innovations:
Hammer Action:
Instead of plucking the strings, small hammers struck them. This allowed for dynamic control, depending on how hard or softly the keys were pressed.
Escapement Mechanism:
Allowed the hammer to fall away from the string after striking it, ensuring that the string could vibrate freely.
Dampers:
Raised when keys were pressed, allowing the strings to vibrate, and fell back down to mute the strings when the keys were released.
These innovations allowed musicians to achieve a wide range of dynamics, from soft to loud, and to play with more expressiveness and nuance.
This capability was a breakthrough in the instrument's development, leading to the piano's rapid adoption by composers and musicians.
Evolution of the keyboard and the 12-note system
Early pianos had a range of around four to five octaves (about 49 to 61 keys). Over time, the range expanded as composers and musicians demanded more notes to explore more complex harmonies and wider ranges.
The standardization of the 12-note chromatic scale into the piano keyboard layout can be traced back to the Baroque period when music theorists and composers began to fully embrace equal temperament tuning.
Equal temperament is a tuning system that divides the octave into 12 equal parts (semitones), allowing all intervals to be slightly adjusted so that all keys sound relatively in tune.
This tuning became the foundation for the modern Western scale and enabled the use of the full chromatic scale across all keys without significant dissonance.
Significance of the chromatic scale
The chromatic scale divides the octave into 12 equally spaced pitches (semitones).
The development and acceptance of this scale were essential in standardising the piano's design, which ultimately led to the inclusion of the 88 keys found on modern pianos.
The chromatic scale allows for modulation to any key, enhancing the piano's versatility and range.
Expansion of the piano keyboard
By the late 18th and early 19th centuries, the piano underwent significant changes to its size, range, and mechanics:
Range Expansion: The range of the piano keyboard was gradually extended.
By 1800, the standard range was about five octaves (61 keys), but it quickly expanded:
Early 1800s: Six octaves (73 keys)
Mid-1800s: Seven octaves (85 keys)
Late 1800s: Seven octaves plus a few additional keys, ultimately leading to the standard 88-key piano (spanning seven octaves plus a minor third, from A0 to C8).
This expansion was driven by the demands of composers such as Beethoven, Chopin, Liszt, and Schumann, who were pushing the boundaries of piano music and required a broader range of pitches and more dynamic possibilities.
Changes in piano mechanics
The 19th century saw numerous mechanical innovations that improved the piano's sound, volume, durability, and responsiveness:
Iron Frame:
Introduced in the 1820s, the iron frame replaced the wooden frame and allowed for much “higher string tension, leading to a louder, richer sound and improved durability.
Double Escapement Action:
Invented by Sébastien Érard in 1821, this mechanism allowed for faster note repetition. It enabled the hammer to be reset without being fully lifted from the key, allowing pianists to play rapidly repeated notes more easily and accurately.
Cross-Stringing:
Introduced in the mid-19th century, this innovation involved strings being crossed diagonally over the soundboard, allowing for longer strings and a more compact design. It increased the instrument's resonance and richness of sound.
These mechanical improvements were essential in establishing the modern piano as a powerful and expressive instrument capable of a wide range of dynamics and colours.
Standardisation of the 88-key keyboard
By the late 19th century, the modern 88-key piano became the standard. This design was popularised by piano manufacturers like Steinway & Sons and included:
7 Octaves plus a minor third:
The standard 88 keys span from A0 (the lowest note) to C8 (the highest note), covering 7 octaves plus an additional minor third.
12-Note System: The keyboard layout reflects the 12-note chromatic scale, consisting of 7 white keys and 5 black keys per octave. This layout is directly tied to the equal temperament tuning system, which allows for consistent sound quality across all keys.
The role of microtones and their exclusion
Microtones, or intervals smaller than a semitone, have largely been excluded from the standard piano keyboard. This exclusion is due to several factors:
Western music tradition:
The 12-note equal temperament system became the foundation of Western music theory and practice, especially from the Baroque period onward.
This system allowed composers to modulate between different keys seamlessly, which was essential for harmonic exploration.
Keyboard design constraints:
Including microtones would significantly complicate the keyboard's design and make it more challenging for pianists to play, as it would require a larger keyboard or a different layout, potentially reducing the instrument's playability and accessibility.
Limited demand:
While microtones are used in some world music traditions (like Arabic, Persian, or Indian music) and certain modern compositions, the demand for microtonal capabilities has been limited in Western classical and popular music contexts.
Most pianos remain designed to cater to the broader musical tradition that relies on the 12-note chromatic scale.
The 20th and 21st centuries
Modern Innovations and Alternatives - While the 88-key, 12-note chromatic piano remains the standard, the 20th and 21st centuries have seen several experiments and innovations:
Microtonal Pianos:
Some contemporary composers and experimental musicians have explored microtonal pianos, which are specially designed to play microtones.
These pianos have a different key arrangement or additional keys to accommodate smaller intervals.
Digital and Hybrid Pianos:
The advent of digital technology has led to the creation of digital pianos, which can emulate a wide variety of tuning systems, including microtonal scales, at the push of a button.
Hybrid pianos combine acoustic and digital elements, offering expanded capabilities.
Conclusion
The development of the modern piano with 88 keys is the result of centuries of innovation in both music theory and instrument technology.
From the early keyboard instruments to Cristofori's pianoforte, through the mechanical advancements of the 19th century and the standardization of the 12-note chromatic scale, the piano has evolved into a versatile instrument with a wide range of expressive capabilities.
The exclusion of microtones reflects the dominance of the equal temperament system and the practical constraints of keyboard design.
However, the piano continues to adapt and evolve, embracing new technologies and musical possibilities while retaining its core design principles.
