Diatonic accordions typically feature the reeds for one to three keys and relevant bass notes/chords, without all the sharps and flats found on chromatic accordions.
Some diatonic accordions utilize bass buttons with bisonoric (two note playing) functionality that adapt to bellows movement direction; this feature is typically found with single row and double row boxes tuned CGDA.
Diatonic
Learning two-row diatonic button accordion can be challenging, yet one of its greatest difficulties lies in understanding its differences from chromatic instruments. Diatonic refers to musical scales without sharps or flats while chromatic refers to full chromatic scales.
Mechanically, diatonic and chromatic accordions differ at their valves: each has two blades that vibrate when air enters or exits the bellows; one produces notes when pulled while another does when pushed.
Accordions were originally designed as an affordable piano alternative for folk dances. Since their invention, accordions have evolved into more sophisticated musical instruments used by many musicians as a form of self-expression through music and culture.
Chromatic
The chromatic accordion is a double action instrument with keyboards arranged chromatically – much like piano keys – to produce consistent notes when opening or closing its bellows, making it easier to play an array of melodies than its unisonoric bandoneon counterpart.
The melody side buttons create notes of a diatonic scale while bass buttons arranged in pairs to play chords allow you to access all harmonic minor keys without switching keys.
Most chromatic accordions are three row instruments with the third row being either one semitone higher than the middle or four tones below the first row. This makes playing various melodies and chords much simpler as moving your fingers just one or two rows will get you there more quickly than returning back to where you started from scratch.
Semitone
Diatonic accordions only feature one or two keys per scale, while those equipped with chromatic keyboards can play all notes within any given key – making them more flexible and convenient to use by musicians who specialize in performing various styles of music.
There are various diatonic accordions available today, from Russian garmons and Steirische Harmonikas used for Alpine music, to Basque trikitixas with up to five rows of treble buttons and 12 unisonoric bass buttons for rhythm and harmony.
The diatonic keyboards are organized in a circle of fifths, which allows an accordionist to move between chords without changing the direction of their bellows. Furthermore, right-hand keys change notes with bellow direction whereas left-hand bass buttons do not.
One row
One-row melodeons are typically tuned to one key and only feature buttons on their melody side that sound diatonic scales, limiting both keys that can be played and tunes that can be performed; but this shouldn’t dissuade anyone from taking up playing this amazing little instrument!
One-row instruments make it easier to play rhythms and chordal melodies than more widely spaced keyboards like piano accordions or chromatic accordions, making this type of arrangement particularly suitable for Irish music and genres that employ chordal/arpeggio phrasing – something especially crucial in genres like bluegrass or jazz where chordal/arpeggio phrases may feature heavily.
Two row
The two row accordion is an indispensable instrument of Irish music. Typically featuring one row of ten keys on the keyboard and eight to twelve bass buttons on its other side, this instrument boasts great appeal as an instrument of expression and musical versatility.
Beginner players will find this arrangement less intimidating as it reduces hand movement and finger travel. Furthermore, it makes for an excellent option when looking to learn traditional Irish dance tunes such as reels and jigs.
Although a 2-row B/C guitar may appear complex, its chromatic nature allows you to access all the notes necessary for playing any key. That being said, playing in any key requires excellent technique as well as understanding chord progressions.
Three row
Three row accordions are an increasingly popular choice among Cumbia and Nortena musicians, functioning similarly to two row boxes but featuring an additional row. Furthermore, these chromatic instruments can play all notes from the chromatic scale simultaneously.
One approach to understanding the B system is viewing it as moving down in full tones; another method involves viewing it as semitones moving upward. Both approaches seem equally valid; one may feel more open or restricted than the other.
Use the thumb when performing chromatic runs to help with multi-octave arpeggios more comfortably and avoid fingertip playing styles that strain your hand. This will make for more comfortable playing.