Editing Accordion (section)

===Variable components===
The term ''accordion'' covers a wide range of instruments, with varying components. All instruments have reed ranks of some format, apart from reedless [[digital accordion]]s. Not all have switches to change registers or ranks, as some have only one treble register and one bass register. The most typical accordion is the piano accordion, which is used for many musical genres. Another type of accordion is the button accordion, which is used in musical traditions including Cajun, Conjunto and [[Tejano music]], Swiss and Slovenian-Austro-German Alpine music, and Argentinian tango music. The [[Steirische Harmonika|Helikon-style]] accordion has multiple flared horns projecting out of the left side to strengthen the bass tone. The word "[[Helicon (instrument)|Helikon]]" refers to a deep-pitched tuba.

====Right-hand keyboard systems====
Different systems exist for the right-hand keyboard of an accordion, which is normally used for playing the melody (while it can also play chords). Some use a [[button (control)|button]] layout arranged in one way or another, while others use a [[piano]]-style keyboard. Each system has different claimed benefits<ref name="pianovschromatic">{{cite web|url=http://home.swipnet.se/nydana/accordiontest.pdf|author=Dan Lindgren |title=Piano Accordion vs. Chromatic Button Accordion|archive-url=https://web.archive.org/web/20090318050921/http://home.swipnet.se/nydana/accordiontest.pdf |archive-date=18 March 2009}}</ref> by those who prefer it. They are also used to define one accordion or another as a different "type":
* [[Chromatic button accordion]]s and the [[bayan (accordion)|bayan]], a Russian variant, use a buttonboard where notes are arranged [[chromatic]]ally. Two major systems exist, referred to as the B-system and the C-system (there are also regional variants). Rarely, some chromatic button accordions have a decorative right-hand keyboard in addition to the rows of buttons, an approach used by the virtuoso accordionist [[Pietro Frosini]].
* [[Diatonic button accordion]]s use a buttonboard designed around the notes of [[diatonic scales]] in a small number of keys. The keys are often arranged in one row for each key available. Chromatic scales may be available by combining notes from different rows. The adjective "diatonic" is also commonly used to describe bisonic or bisonoric accordions—that is, instruments whose right-hand (and in some instances even bass) keys each sound two different notes depending on the direction of the bellows (for instance, producing major triad sequences while closing the bellows and dominant seventh or 7–9 while opening). Such is the case, for instance, with the Argentinian [[bandoneon]], the Slovenian-Austro-German [[Steirische Harmonika]], the Czech Heligonka Harmonika, the Italian [[organetto]], the Swiss [[Schwyzerörgeli]] and the [[Anglo concertina]].
* [[Piano accordion]]s use a [[musical keyboard]] similar to a piano, at right angles to the cabinet, the tops of the keys inward toward the bellows.
**The rarely used bass accordion has only a right-hand keyboard, with ranks of 8', 16', and 32' reeds, with the lowest note being the deepest pitch on a pipe organ [[pedal keyboard]] (pedal C). It is intended for performing [[bassline]]s in accordion orchestras.
**The rarely used piccolo accordion also has only a right-hand keyboard.
* [[Jankó keyboard|6-plus-6]] accordions use a buttonboard with three rows of buttons in a "uniform" or "whole-tone" arrangement, generally known as a [[Jankó keyboard]]. The chromatic scale consists of two rows. The third row is a repetition of the first row, so there is the same fingering in all twelve scales. These accordions are produced only in special editions e.g. the ''logicordion'' produced by [[VEB Klingenthaler Harmonikawerke|Harmona]].
<gallery>
Italian Button Accordion QM r.jpg|A button key accordion made by the company Marrazza in Italy. It was brought by Italian immigrants to Australia as a reminder of their homeland.
PianoAccordeon.jpg|A ''Weltmeister'' piano accordion by [[VEB Klingenthaler Harmonikawerke]]
</gallery>

====Left-hand keyboard systems====
[[File:120-button Stradella chart.svg|thumb|right|300px|Typical 120-button Stradella bass system. This is the left-hand keyboard system found on most unisonoric accordions today.]]
Different systems are also in use for the left-hand keyboard, which is normally used for playing the accompaniment. These usually use distinct bass buttons and often have buttons with concavities or studs to help the player navigate the layout despite not being able to see the buttons while playing. There are three general categories:
[[File:Bassmechanics.jpg|thumb|right|200px|The bass buttons trigger a complex mechanism of wires, rods, and levers, which is normally hidden inside the instrument.]]
* The [[Stradella bass system]], also called ''standard bass'',<ref>{{Cite web |title=Push Those Buttons! |url=https://accordionlifeacademy.com/articles/push-those-buttons |access-date=2024-08-16 |website=Accordion Life Academy |language=en}}</ref> is arranged in a [[circle of fifths]] and uses single buttons for bass notes and additional rows of single buttons for preset major, minor, dominant seventh, and diminished [[chord (music)|chords]]. The dominant seventh and diminished chords are three-note chord voicings that omit the fifths of the chords. 
* The Belgian bass system is a variation used in Belgian chromatic accordions. It is also arranged in a circle of fifths but in reverse order. This system has three rows of basses, three rows of chord buttons allowing easier fingering for playing melodies, combined chords, better use of fingers one and five, and more space between the buttons. This system was rarely used outside of its native Belgium.
* Various [[free-bass system]]s for greater access to playing melodies and complex [[bassline]]s on the left-hand keyboard and to forming one's own chords note-by-note. These are often chosen for playing [[jazz]] and [[classical music]]. Some models can convert between free-bass and Stradella bass; this is called ''converter bass''. The free-bass left hand notes are arranged chromatically in three rows with one additional duplicate row of buttons.
* Luttbeg double-keyboard piano accordions have a piano keyboard layout on both the treble and bass sides. This allows [[pianists]], most notably [[Duke Ellington]], to double up on the accordion without difficulty. The [[Bercandeon]] is an improved version of that instrument, also making it a "keyboard bandoneon".
* In 2021, a patent was published by Valerio Chiovarelli for a new bass system called the "Chiovarelli Jazz System".<ref>{{cite web | url=https://patents.google.com/patent/IT202100003890A1/en?q=(Chiovarelli)&q=G10D11%2f00 | title=Sezione dei bassi di una fisarmonica e fisarmonica comprendente tale sezione dei bassi }}</ref> This system is a variation of the Stradella bass system where, instead of triads, the chordal buttons of this system produce bichords (chords with only 2 pitches instead of 3).<ref>{{cite web | url=https://www.chiovarellijazzsystem.com/cjs/ | title=CJS &#124; Chiovarelli Jazz System }}</ref> The "Chiovarellia Jazz System" (or "CJS" for short) prioritizes the effectiveness of left hand accordion in jazz music, hence the name of the system, but according to the inventor, these chords can be useful when playing many varieties of music.

====Reed ranks and switches====
{{main|Accordion reed ranks and switches}}
[[File:reedsinset.jpg|upright=0.75|thumb|right|Accordion [[Accordion reed ranks and switches|reed ranks]] with closeup of reeds]]

Inside the accordion are the reeds that generate the instrument tones. These are organized in different sounding ''banks'', which can be further combined into ''registers'' producing differing ''[[timbre]]s''. All but the smaller accordions are equipped with switches that control which combination of reed banks operate, organized from high to low [[register (music)|registers]]. Each register stop produces a separate sound timbre, many of which also differ in octaves or in how different octaves are combined. See the [[accordion reed ranks and switches]] article for further explanation and audio samples. All but the smaller accordions usually have treble switches. The larger and more expensive accordions often also have bass switches to give options for the reed bank on the bass side.

====Classification of chromatic and piano type accordions====
In describing or pricing an accordion, the first factor is size, expressed in number of keys on either side. For a piano type, this could for one example be 37/96, meaning 37 treble keys (three octaves plus one note) on the treble side and 96 bass keys. A second aspect of size is the width of the white keys, which means that even accordions with the same number of keys have keyboards of different lengths, ranging from {{convert|14|in|cm}} for a child's accordion to {{convert|19|in|cm}} for an adult-sized instrument. After size, the price and weight of an accordion is largely dependent on the number of reed ranks on either side, either on a [[Accordion reed ranks and switches#Cassotto|cassotto]] or not, and to a lesser degree on the number of combinations available through register switches. The next, but important, factor is the quality of the reeds, the highest grade called "a mano" (meaning "hand-made"), the next "tipo a mano" ("like hand-made"), lower grades including "export" and several more.

Price is also affected by the use of costly woods, luxury decorations, and features such as a palm switch, grille mute, and so on. Some accordion makers sell a range of different models, from a less-expensive base model to a more costly luxury model. Typically, the register switches are described as ''Reeds: 5 + 3'', meaning five reeds on the treble side and three on the bass, and ''Registers: 13 + M, 7'', meaning 13 register buttons on the treble side plus a special "master" that activates all ranks, like the "tutti" or "full organ" switch on an organ, and seven register switches on the bass side. Another factor affecting the price is the presence of electronics, such as condenser microphones, volume and tone controls, or MIDI sensors and connections.

[[File:Quito Accordion player.jpg|thumb|Accordion player on a street in the historic centre of [[Quito]], Ecuador]]

====Straps====
The larger piano and chromatic button accordions are usually heavier than other smaller [[squeezebox]]es, and are equipped with two shoulder straps to make it easier to balance the weight and increase bellows control while sitting, and avoid dropping the instrument while standing. Other accordions, such as the [[diatonic button accordion]], have only a single shoulder strap and a right hand thumb strap. All accordions have a (mostly adjustable) leather strap on the left-hand side to keep the player's hand in position while drawing the bellows. There are also straps above and below the bellows to keep it securely closed when the instrument is not being played.

====Electronic and digital====
{{Main|Digital accordion}}
[[File:Rainer von Vielen-Heimatsound-2015 (12).jpg|thumb|right|200px|Rainer von Vielen playing a Roland digital V-Accordion. The bank of electronic switches can change the accordion's sound, tone and volume.]]
In the 2010s, a range of electronic and digital accordions were introduced. They have an electronic [[sound module]] which creates the accordion sound, and most use [[MIDI]] systems to encode the keypresses and transmit them to the sound module. A digital accordion can have hundreds of sounds, which can include different types of accordions and even non-accordion sounds, such as pipe organ, piano, or guitar. Sensors are used on the buttons and keys, such as magnetic reed switches. Sensors are also used on the bellows to transmit the pushing and pulling of the bellows to the sound module. Digital accordions may have features not found in acoustic instruments, such as a piano-style [[sustain pedal]], a modulation control for changing keys, and a [[portamento]] effect.

As an electronic instrument, these types of accordions are plugged into a [[PA system]] or [[keyboard amplifier]] to produce sound. Some digital accordions have a small internal speaker and amplifier, so they can be used without a PA system or keyboard amplifier, at least for practicing and small venues like [[coffeehouse]]s. One benefit of electronic accordions is that they can be practiced with headphones, making them inaudible to other people nearby. On a digital accordion, the volume of the right-hand keyboard and the left-hand buttons can be independently adjusted.

Acoustic-digital hybrid accordions also exist. They are acoustic accordions (with reeds, bellows, and so on), but they also contain sensors, electronics, and MIDI connections, which provides a wider range of sound options. An acoustic-digital hybrid may be manufactured in this form, or it may be an acoustic accordion which has had aftermarket electronics sensors and connections added. Several companies sell aftermarket electronics kits, but they are typically installed by professional accordion technicians, because of the complex and delicate nature of the internal parts of an accordion.