Button accordions go by various names, yet all share similar designs. Each includes a melody-sized keyboard with diatonic scales for pitch organization of its buttons.
Accordions can provide an engaging user experience by increasing content without creating too much scrolling. However, they should be used with caution in order to meet accessibility standards and remain compliant.
Keyboard
A button accordion features a melody-sized keyboard with rows of buttons arranged chromatically according to pitch, enabling melodies to be played at true pitch while using the same bass notes as found on piano accordion.
Button accordions provide greater versatility, being capable of playing various genres including classical pieces. Furthermore, their smaller and lighter design make them much easier to transport.
Bass buttons are grouped in sets of two to produce major, minor and seventh chords on an accordion; each set forms one voice (an accordion can have up to five voices). Each voice produces specific combinations of treble reeds that allow for different harmonic effects when playing; this system can be found on Irish melodeons like those owned by late Paddy O’Brien and Finbarr Dwyer’s instruments.
Bass
Button accordions generally feature one diatonic keyboard of ten rows, yielding twenty notes. These notes can be played by compressing and expanding the bellows; doing this produces air pressure while expanding it creates vacuum pressure, which causes vibrating reeds that produce sound to vibrate back out as sound vibrations.
The treble side features buttons arranged in a chromatic pattern, enabling players to easily and effortlessly play different musical scales and arpeggios.
Button accordions are single action instruments, producing different pitches depending on whether their bellows are drawn back in or pressed/squeezed (similar to exhaling and inhaling on most harmonicas). This makes them smaller and lighter than their chromatic piano or chormatic counterparts while still permitting players to easily produce bass register notes and chords with ease – something particularly useful for Irish traditional musicians such as Paddy O’Brien and Finbarr Dwyer.
Treble
Treble buttons, which provide melodies on an accordion, can be found on its right side and arranged according to a circle of fifths pattern; when pressing bellows each row will go one fifth higher and create an expansive variety of melodies while being easy on fingers.
Inner treble rows are often combined in pairs to produce different chords. For instance, on an accordion in the key of G, pairing up its first treble button with B is often done so as to facilitate playing traditional Irish reel music, which involves two bar sequences of music.
Alternative uses for outer treble rows include playing single note runs. Unfortunately, these can quickly become repetitive and boring if they’re repeated all too frequently.
Reeds
Button accordions feature two sets of reeds – one on the left side (melody), and another one on the right side. A single-action bellows must be pulled and squeezed alternately to activate these reeds and keep playing music.
The right-hand button side produces melody notes, while the left-hand side contains bass and chord buttons which can create various combinations using pre-set major, minor, seventh, and diminished chords. Additionally, there are various notes and arpeggios that can be played using both columns – both can produce melodies with melodies of their own as well.
Accordions vary significantly in terms of size, cost, quality and features. Different models feature different layouts between their treble and bass sides as well as how many keys they use and reed banks they employ; some models also come equipped with a “chin switch,” enabling performers to change reeds with just the flick of their chin rather than having to use hand buttons for this action.
Bellows
The accordion is a bellows-driven, free reed aerophone that produces sound when air flows past a reed. It combines melody and accompaniment in one instrument with its keyboard/treble buttons on the right-hand side and bass or pre-set chord buttons on the left side.
On the bass side, each button corresponds to a note in the scale; pressing or pulling one causes bellows movement in that direction and thus produces sounds from different octaves.
For bass buttons, the layout resembles that of an arrangement in a circle of fifths; each column ascends by fifth from middle C. To help understand this better, check out an excellent UK melodeon website (click to open in new tab) where there is also a diagram that demonstrates this feature and also how treble buttons correspond with piano keys.