Types of accordions and how they work - Diatonic Accordions
Diatonic Accordions

Diatonics in General

The first diatonic accordions were made early in the 1800's. They had one row of ten buttons in the right hand.

Article titled "The Diatonic Accordion".

For each note on the button board there are at least two reeds (and can be up to ten) with different pitched reeds for the "in" bellows and "out" bellows. The bass notes and relevant chords are the root of the scale for the in bellows and the fifth of the scale for the out bellows.

Diatonics are frequently used by many folk and dance groups, because of their great sound output, simplicity, light weight and low cost. This makes them one of the most popular accordions worldwide. The note pattern of the keyboard is usually identical to the mouth harmonica.

One row Diatonic

The one row diatonic, melodeon or, as it is sometimes referred to "German style accordion", has one ten button row as its keyboard. As it is diatonic it has twenty notes available from them; ten on the "in" bellows and ten on the "out" bellows. There are two diatonic bass buttons, giving a total of two bass notes and two chords. The bass notes and relevant chords are the root (first note) of the scale for the "in" bellows and the fifth of the scale for the "out" bellows.


Found in Italy the Organetto has up to twenty-four treble buttons and twelve bass buttons. The most popular type has two bass buttons and one row of ten treble buttons. A second row with three or four buttons enables different fingerings. It has up to three reeds per note; the two in the middle set are tuned with a tremolo the third is an octave lower.

Two row Diatonic

The origins of two row diatonic accordions are unclear, as many versions appeared around the world simultaneously. To increase its range and compatibility with other instruments another row of buttons was added to the keyboard.

The second row is also diatonic and can either be one half tone above the first row (eg. scales of B and C) or a perfect fourth above the first row (eg. G and C). These can be in different keys from the examples here. In the case of the semitone diatonic, it can play every note in the chromatic scale.

Italian Diatonic

The Italian Diatonic has two rows, with the second row a perfect fourth above the first row. An additional partial third row usually consists of five or six buttons of accidentals (relevant sharps or flats). Also one note in the second row is called the gleisch tone. This means it plays the same tone regardless of bellows direction. This note is always the perfect fifth (middle octave only) of the relevant diatonic scale.

Three row Diatonic

Three row diatonic accordions are similar to the two row diatonics with the third row either a semi tone higher than the original (now middle) row, or a fourth above the second row. It is possible to have accordions with up to twelve bass notes. The bass notes and relevant chords are the root of the scale for the in bellows and fifth of the scale for the out bellows. There are also four and five row diatonic accordions available, following the same patterns.

Helikon Accordion

The Helikon accordion is named after the Helicon "Tuba", which evolved from ram horn trumpets, first used thousands of years ago. It is the Helikon bass reeds which give it a distinctive "Tuba" sound to the bass notes. This is because the bass reeds are much longer and wider than "normal" bass reeds. They reproduce low pitched tones like a Tuba. Quite often the low Helikon reeds are fitted to a single duraluminium plate.

These reeds can be up to 1 inch longer than standard bass reeds. First used in Styrian diatonic accordions, these reeds are now found in piano accordions.

Shand Accordion

This was developed by Scottish accordionist Jimmy Shand. There is a three row semitone diatonic on the right hand keyboard and 96 bass standard system for the left hand. The right hand rows change notes with different bellows directions, the left hand bass notes do not.
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