A piano is a complex instrument – what do the different parts of a piano do? We find out…
Though from the outside, a piano may seem like a simple proposition, but a cursory glance inside reveals just how complex this instrument is. The mechanics that are involved for a piano to generate a sound encompass a huge number of components.
To help understand this, here’s a mini guide to explain what the various key parts of a piano actually do. By doing so, it should provide an explanation of how a piano generates its sound.
To explain the process of how a piano generates its sound, it’s easiest to start from the position of the player. The piano action is the term given to the mechanism that translates the pressing of keys into the sounding of notes.
The piano action is an astonishingly complex piece on design (see the diagram below). Ultimately, when a key (Ky in the diagram) is pressed, it causes a hammer (H) to be thrown forward onto the strings, sounding a note.
The hammers, as you may have already gathered from above, are the bits that actually cause the piano’s notes to sound. Hammers are typically made of wood, with layers of felt (or sometimes leather) covering the point that it contacts the piano strings. It is this felt layer that gives the piano its characteristically soft attack. The harder this layer is, the brighter, and harder the attack of the piano sound will be.
Piano strings are made from piano wire (surprise, surprise…) This is high carbon steel wire, which must be capable of undergoing incredible strain, and has to be produced to incredibly low tolerances.
As it is stretched over the soundboard, the tension in these strings is huge. Plus, repeated beatings with a hammer, and exposure to humidity and climatic changes provide additional challenges to the integrity of the piano string. They’re expected to last a lifetime, too.
Typically, each note will have two or three strings. Differences in tuning between these matched strings are the cause of the strange detuned ‘beating’ that can occur on an out of tune instrument.
When an upright piano is described as ‘overstrung’, it means that the bass strings run diagonally across the treble strings.
You may have noticed that holding the key down on a piano will hold the note (i.e. it will continue to play) until the key is released. This is because of dampers.
In their normal resting position with no keys pressed, the dampers, which have a surface of soft felt, rest on the strings to stop vibration. When the key is pressed and held, the damper is held away from the string, allowing the strings to continue to sound. When the key is released, the damper returns to the string.
In addition, the dampers stop non-played strings sounding ‘sympathetically’ when other notes are played (see here for more info on sympathetic resonance).
The damper pedal allows notes to ring after keys have been released. It does this by raising all of the dampers of the strings whilst the pedal is depressed.
The soundboard is arguably the most important component in a piano’s construction. It is this piece of wood (spruce) that resonates when strings vibrate, giving the piano its unique tone. Like a guitar or other stringed instrument, the vibration from the strings is directed into the soundboard through a bridge that rests upon it.
These are the key components responsible for piano tone. There are, of course, differences between models and manufacturers, but understanding what these components do will certainly help to understand what these differences are, and the effect they may have.
You can find a full range of acoustic pianos in our online store here.
Joe is a contributor for the Dawsons Music blog. Specialising in product reviews and crafting content to help and inspire musicians of all musical backgrounds.