Just as an octagon has eight sides and an octopus has eight appendages, a musical octave is an interval spanning eight notes.
This term, pronounced OCT-iv, is derived from the Latin expression octava dies, referring to the eighth day of a festival (no, not a funeral). It may also refer to the eight-line stanza in an Italian sonnet.
An interval in music consists of two notes spaced a certain distance apart. An octave, also notated as P8 (Perfect 8th) is bookended by the first and last notes of a scale.
How many octaves are on a piano? The traditional piano has 88 keys, spanning seven full octaves. There is also a 49-key piano (four octaves), a 61-key piano (five octaves) and a 76-key piano (six octaves).
The octave is perhaps the easiest interval to remember because these notes are one and the same, although they are located in different registers.
For example, an octave built on C is C to the next C, an octave built on A is A to the next A and an octave built on F# is F# to the next F#.
How many octaves does a piano have?
The answer to this question is multifold since pianos, like humans, come in (almost) all shapes and sizes. First, let’s consider two predecessors of the piano, the clavichord and the harpsichord, as well as a similar instrument called the celesta. Finally, we will look at the different keyboard lengths of the modern piano.
The clavichord was developed from the medieval monochord and was widely used throughout the Renaissance, Baroque and Classical periods. Its soft sound quality made it more conducive to intimate performances. Utilizing a hammer-and-string mechanism (just with metal blades rather than wooden hammers), the clavichord is the closest relative of the piano. Its keys span five full octaves.
The harpsichord was first designed in Italy in the 16th century. It utilizes a string-plucking mechanism, unlike the clavichord and piano. Its popularity spread quickly throughout Europe, and it supported the music of the Baroque era. By the mid-18th century, the instrument had evolved into a keyboard with 60 keys (five full octaves). By this time, however, the relatively new piano began to rival its popularity.
The celesta, derived from the French word for “heavenly,” is a delicate, bell-like instrument resembling the combination of a glockenspiel and metallophone. You may recognize its unique sound from the “Sugar Plum Fairy” solo of Tchaikovsky’s Nutcracker ballet, a part traditionally played on the celesta. The instrument looks like a small piano, but its sound mechanism is slightly different. Instead of striking strings, the felt hammers strike steel plates positioned on top of wooden resonators. Like the clavichord and harpsichord, the celesta typically boasts a range of five octaves.
Technically speaking, the piano originated from the dulcimer, an instrument created in the Middle East that spread to Europe in the 11th century. It consists of a box resonator with strings stretched across it that are struck by a hammer. Then, the developments of the clavichord and harpsichord eventually led to Bartolomeo Cristofori’s creation of the “clavicembalo col piano e forte,” which is Italian for a harpsichord that can play soft and loud noises. Thus, the piano introduced a new instrument that could portray both the grandiosity of the orchestra and the delicacy of bells–and (almost) everything in between.
Octaves in piano literature
Since octaves simply double the same note, you may wonder why they are important or necessary. However, they are frequently used throughout almost all piano literature, and they play an important role in composition. They add volume and depth that can’t be achieved with just one note.
They are most often used in the left hand, or harmony, of the piece. However, they may also appear in the melody. Consider, for example, the first three notes of Rachmaninoff’s C# Minor Prelude. These notes–A, G# and C#–form a startling descending line that evokes a dramatic and dangerous vibe, as if someone were diving off a cliff. They function both melodically and harmonically. More importantly, their startling effect is created by two elements: 1) the unconventional intervals between the notes and 2) the use of three octaves for each note. This layering creates a portentous character that distinguishes the entire piece.
This would be quite different if simply one note were used. The heavy, ominous mood would become eerie and maybe even anemic.
Octaves, particularly octaves played simultaneously, are a distinguishing element of piano music. While other instruments can play octaves, they are easiest to navigate on a piano. String instruments such as the violin and cello can play octaves through a double stop, a technique that allows two notes to be played simultaneously. However, only pianists can play more than two notes at once.
Octave technique tips
Playing octaves on the piano is no easy task. First of all, not everyone can reach an octave with one hand. However, with the right technique, it’s amazing what pianists can accomplish.
For example, almost everyone can play an octave tremolo. To do this, simply expand your hand as far as you can and bounce between your thumb and pinky, keeping the energy focused at the center of the octave. Rotating your forearm to generate movement will keep your hands from tensing up and allow for a faster tremolo.
Octave scales are also a popular technique activity. These can be played in one of two ways: simultaneously or staggered. To play them simultaneously, first stretch your fingers to grasp the full octave (if possible). Then, after playing each octave, release the keys and allow your hand to return to its normal position. Repeat this process for each note along the scale. You can do this exercise with major, minor and even chromatic scales for a bonus challenge.
To spice things up, you could try different articulations such as staccato (releasing each key quickly) or legato, which can be accomplished by using the sustain pedal and a particular fingering that alternates between 1-5 and 1-4 (thumb to pinky and thumb to ring finger).
If your fingers simply won’t reach a full octave, you can try staggering the octaves. This version uses the same technique as the tremolo activity described above. For example, to play a C Major scale using your right hand, play C with your thumb and rotate your forearm so you can reach the next C with your pinky. Repeat this process with the remaining notes.
The octave is just one example of how versatile the piano is. While it is a simple concept–literally the doubling of a single note–this interval has extraordinary capabilities in both composition and performance.
So, next time someone asks if you have a special skill, say you’re an expert at playing octave tremolos.