Classification of musical instruments:
By physical method: The string instruments and the woodwinds.
By material: Metals, woods, stone, skin, gut strings.
By tone quality: Brasswind instruments, woodwinds using reeds as mouthpieces (except some brass instruments such as sax), strings of various materials, and some percussion.
By function: Idiophones (those whose sound is caused by an actual object vibrating in a regular way). Membranophones (whose sound is produced by a vibrating membrane). Aerophones (whose sound is obtained by the vibration of air set in motion through wind instruments or organ pipes). Electrophones (by vibrations conveyed to electric current or wire) Musical box, Grammophone, Phonograph, Graphophone.
By note-volume relationship: Instruments producing definite pitches (keyed or otherwise tuned), and instruments having no pitch or indefinite pitch (such as cymbals).
An organ in this classification
Pipe organ: Large, usually stationary instrument consisting of one or more rows of pipes housed in a wooden case with doors and shutters. It is operated by the player sitting at the console, one row for each manual (keyboard), which are provided with keys corresponding to actual tones, arranged in keyboard fashion with independent pedals at the base of each row. The air passing through the pipe causes it to vibrate at its natural frequency or some submultiple thereof; this produces sound waves that are collected by an open-end, called a flue, and channeled into a wind-collecting chamber, called a windchest.
The power supply for most organs is compressed air, supplied either from an electric motor or bellows operated by the foot; it is then maintained under pressure, and released to the pipes through a series of valves. The console (keyboard) controls which rank of pipes is sounded: swell shutters, opened or closed by stop actions, allow more or less air to reach selected ranks.
The organ has four basic divisions:
- Great division – the larger division; contains fewest stops but produces most volume;
- Swell division – part of great division where expressiveness is emphasized;
- Choir division – the smaller division; used for accompaniment;
- Pedal division – contains longer pipework in larger scaled resonating chambers.
Piano in this classification
Piano: an instrument similar to a large upright cabinet, having a metal frame and sounding board above, solid wooden wings on either side, and a keyboard placed at an angle of about 30 degrees so as to be easily reached by both hands of the performer. The modern piano is usually fitted with 88 keys (seven octaves) or 85 keys (eight octaves). These are arranged in groups of twos or threes called chords, each chord consisting of one key for each note sounded by its group of strings.
Each key has under it three hammers– two for the string, one for the soundboard– and a damper; thus, when a key is struck by the finger the string is set in vibration either directly if it is free, or through two intermediate points of attachment to other strings from which it receives its pitch. The tone therefore produced by each set vibrating another group of strings tuned to this same note so that a continuous sound results.
The number of chords and notes constituting a full piano harmony depends on the length and width of the keyboard: seven octaves being usual but eight or even more occasionally being chosen. Each key must have at least three wires stretched between felt-covered hammers attached to its tail and corresponding "tangents" (small levers) fastened to the wood of the keyframe.
The modern piano is usually fitted with 88 keys (seven octaves) or 85 keys (eight octaves). These are arranged in groups of two or three called chords, each chord consisting of one key for each note sounded by its group of strings
Organ vs Piano
Both instruments sound different mainly because organs make use of vibrating membranes (such as vocal cords), whereas pianos use vibrations communicated through stretched wires. The only real difference between them is that an organ makes use of a keyboard to control which rank of pipes will be sounded - rather like pressing buttons on an electronic keyboard.
The piano is typically made from wood with metal strings, whereas most organs are constructed from wood and metal tubing for the internal pipework (although there are some exceptions, such as the tubular-pneumatic organ). An organ console does not have a keyboard as such – instead, it has stops that control which ranks of open pipe mouths are brought into action at each manual or pedal division.
The difference in prices:
The cost of a concert grand is usually in the range of $30,000 - 100,000. The price depends on the scale and action of keys, finish, width and length of the keyboard, size of the soundboard, case construction, type of pedals, and other factors. In comparison with a large pipe organ which can cost millions for one instrument. The cost of an organ depends on the size and type and varies from $10,000 to several million dollars.
The difference in size:
Piano: usually comes in a standard 6 ft (1.8 m) length, and also in an "upright" form—usually around 5 feet (1.5 m).
Organ: one of three types: free-standing console organ; detached console organ; and electronic church organ. Console organs have the largest variation in physical size with some tabletop models about 1.5 meters wide and 28 cm tall and weighing less than 10 kg; to large instruments that can weigh more than 14,000 kilograms, measuring eight meters wide, four meters deep, and two or three meters tall. The smallest self-contained portable console is 61 centimeters deep by 220 centimeters wide by centimeters high (24 in × 7.9 ft × 0.4 ft); the largest is around three meters wide, four meters deep, and weighs about 3.5 tonnes.
The difference in construction:
A piano does not have pedals whereas an organ has two or more sets of foot-operated levers that control which ranks are on at any given time allowing for different combinations of stops to be played simultaneously. The pedalboard also called a "pedal clavier", is an auxiliary keyboard commonly found on organs used to produce bass notes.
Although it was rare before 1850, many concert grands have one built-in today. Organists use the pedals to expand the organ's palette of tonal possibilities. It enables them to play thunderous low sounds with less effort than otherwise be necessary if they had to press down big enough on the organ's own keyboard. Some organs play only on the manuals; or, less commonly on one manual with an independent pedalboard that plays separate bass notes.
The difference in sound:
The piano is known for its distinctive timbre and percussive effect due to its metallic action which strikes steel strings with felt-covered hammers. The acoustic mechanism of the piano creates a complex tone – rich in overtones – which is more powerful than that of other musical instruments played using a similar keyboard.
The pipe organ makes use of enclosed pipes, each producing one pitch (multiple ranks of pipes can be used to create multiple tones ). A pipe organ has air flowing through it to produce sound—the wind caused by the air flowing through the pipes is known as wind pressure. When the keys on a pipe organ are played, a valve opens allowing air to flow until it is stopped by a metal tab (a "stop"). The airflow caused by this tab stops and causes a pressure drop, which either opens or closes various pipes; these, in turn, cause the air flowing into and out of other pipes to produce sound.
The difference in tone production:
On a piano, pressing key results in a felt hammer striking metal strings. The player can vary the intensity of the sound by controlling how hard they strike the keys (the velocity with which each key is struck). This ability to vary the volume is one reason why musicians prefer to play pianos over other keyboard instruments.
The pipe organ also has two methods of controlling the intensity of sound – it may control the wind pressure provided to the pipes, or through variation in what is known as electronic "coupling".
The harder a key on a piano-type action is pressed, the more intense is its sound; and this intensity may be varied by lifting one's finger off and replacing it at different positions along with the keyboard: short leaps ( staccato ) or long glissando (portando). When a key is pressed to initiate sound on an organ, it closes a circuit that activates not just the note that is being played, but all the notes of the rank being used. The stop has no direct effect on loudness; how loudly each rank sounds is set by its own combination action regulating the wind supply.
Both the piano and the pipe organ are keyboard instruments that produce sound through metal strings or air that is set into vibration. The main difference between the two is timbre and volume: the piano produces a very different timbre than does a pipe organ. A pipe organ has many ranks of pipes that individually can be played on their own manual, but this is generally not done except in certain circumstances such as registration changes.
The piano, although it also has multiple ranks of individual notes which can be played on its own manual (as well as using pedals), is mainly configured to play one rank at a time. Also, whereas almost all organs have mechanically-controlled stop knobs that open or close shutoff valves for individual ranks, most pianos do not have shutoff valves for each individual key. For these reasons, the organ is considered to be a more complex instrument than the piano.
The final verdict would be that both instruments are very similar in terms of sound production, but are different in how they're played and what's actually being produced during each performance. It depends on your musical choice as to which instrument you'd prefer to use or learn how to play!