Related
The piano is the most "complete" of the keyboard instruments, and the only instrument on this site whose range spans the entire 88-key compass. It can compress a full orchestral score into two hands — something only it and the organ can do.
It also poses a classification question that has to be stated clearly: it is played from a keyboard, yet it belongs to the chordophones — because the strings vibrate; the keyboard is only the interface.
| Classification | Value |
|---|---|
| HS class | Chordophone — the strings vibrate |
| Sub-type | Keyboard drives a felt hammer action against strings · one to three strings per note · soundboard amplifies · dampers stop the sound |
| Family | Western · Keyboard (struck branch) |
| Bayin | Not applicable — a Chinese system; the piano is outside it |
⚠️ One conceptual point: "keyboard" answers "how it is operated"; "chordophone / aerophone / idiophone" answers "what vibrates". The keyboard group's four instruments make this plain: - Piano: keyboard → struck strings → chordophone - Harpsichord: keyboard → plucked strings → chordophone - Organ: keyboard → air → aerophone - Celesta: keyboard → struck steel plates → idiophone Four keyboards, three great classes. "Keyboard instrument" is a grouping by interface, not by acoustics.
Three mechanisms: dynamics, ring, volume
The piano replaced the harpsichord because three mechanisms came together.
This diagram gives the piano its technical reason to exist (see the comparison below).
Three keyboard trigger types compared
"Mechanism decides the range of control" is the keyboard group's key thread: what an instrument can do is settled by its mechanism first, and only then by a composer's imagination.
Range
钢琴属弦鸣乐器 —— 键盘只是操作界面，振源是弦。标准 88 键，音域 A0–C8，是本站键盘条目的参照尺度：其他键盘乐器的音域都可以在这上面标出位置。
- A0–C8 (88 keys), covering the site's entire keyboard range — the only keyboard instrument here that never needs a "beyond the piano" extension.
- The working range is A0–C7; the top octave belongs mostly to solo and virtuoso writing.
- Its span is the keyboard group's ruler. Reading the harpsichord, clavichord or organ entries, you can see directly where they sit on these 88 keys.
Timbre, and how to hear it
Four cues:
1. A clear attack and a long, controllable tail — the hammer gives the attack, the dampers and pedal manage what follows. 2. Dynamic layering is its language: from almost inaudible to very loud on one instrument — the core reason it became the 19th century's universal instrument. 3. Thick low, bright high, most "vocal" in the middle — composers exploit the differing registers. 4. It is a harmonic instrument: ten fingers can press ten notes, so it naturally carries harmony.
Playing techniques
- Touch controls dynamics, duration and legato.
- Three pedals (modern pianos): right (sustain) lifts all dampers so notes accumulate; left (soft) changes the number of strings or shortens the hammer's travel; middle varies by instrument (selective sustain).
- Legato and staccato: the action allows very fine control of connection — the basis of piano language.
- The "prepared" effect: pressing keys silently first (lifting dampers), then striking, yields a longer ring.
The family
| Instrument | Trigger | Source | Dynamics | Volume | Range |
|---|---|---|---|---|---|
| Piano | struck | strings | yes | large | A0–C8 |
| Harpsichord | plucked | strings | no | medium | F1–F6 |
| Clavichord | struck (tangent) | strings | yes (with vibrato) | tiny | C2–C6 |
| Organ | air | air columns | no (stops instead) | huge | C2–C7 |
| Celesta | struck plates | steel plates | yes | small | C3–C8 |
This table lays out the four technical routes behind the word "keyboard" — one hand, three HS classes, four ranges of control.
History
| Period | State |
|---|---|
| Around 1700 | Cristofori in Italy builds the first keyboard instrument whose touch controls dynamics — the piano begins |
| 18th c. | coexists with the harpsichord for decades; actions improve (Viennese and English types) |
| 19th c. | iron frames, overstringing and felt hammers mature → far more volume and range; it becomes the household and concert-hall universal instrument |
| Later 19th c. | 88 keys (A0–C8) become standard; grand and upright forms settle |
| 20th c. | central to composition, teaching and performance; recording and popular music are built around it |
| Late 20th c. onward | coexists with electronic keyboards; universal in classical, jazz, pop and film |
Its victory has a very practical cause: it can control dynamics. That extra bit of controllability over the harpsichord let music make crescendos and diminuendos at a keyboard for the first time — exactly what the language of the late 18th century required.
Common misconceptions
- "The piano is a keyboard instrument, so it is classed as a keyboard instrument." In Hornbostel–Sachs it is a chordophone — the strings vibrate. "Keyboard" is an interface (the organ in the same group is an aerophone, the celesta an idiophone).
- "The piano and the harpsichord are much the same." Different triggers (struck versus plucked) → a harpsichord cannot control dynamics, the fundamental difference.
- "The pedal just makes it louder." The sustain pedal changes how harmonies stack — part of the language of writing and playing.
- "An upright is a small grand." The strings run in different directions (vertical versus horizontal) and the action differs → different feel and sound.
- "A wide range means it can play anything." The range is wide, but it cannot sustain (a struck note decays) — unlike the organ or strings, and the reason "piano writing" is so distinctive.
Next
The keyboard group's next stop is the piano's predecessor: the harpsichord — the same keyboard and the same strings, but plucked, which produces an entirely different musical language. Beyond it come the clavichord (dynamic but tiny) and the organ (aerophone under a keyboard). :::
Listen in the library
All tracks from midicn-lib — inline badge is the license tier (C1 commercial / C2 non-commercial / C3 study only).
Sources
- 结构依通行制琴资料：键盘经击弦机驱动包毡木槌击弦；每音由一至三根弦构成，弦的振动经音板放大；制音器在离键时止音，右踏板可整体解除
- 「钢琴属弦鸣乐器 —— 振源是弦；键盘只是操作界面」依 Hornbostel–Sachs 分类
- 「标准音域 A0–C8（88 键）」依通行制琴规格
- 「击弦机使音量与音色随触键力度变化 —— 这是它与大键琴最根本的区别」依乐器史与乐器声学
Used for fact-checking only; all prose is original.