Bisonoric Bellows Driven Instruments

Bisonoric instruments, produce different musical notes at each button depending on whether the bellows is opening or closing.

Traditionaly known as diatonic instruments, because all bisonoric instruments were diatonic. That is to say that they only had the notes of one or two diatonic scales, but no accidental notes except on additional buttons. However, the term diatonic is often used imprecisely as some instruments that use an arrangement of two different diatonic scales are, in fact, chromatic as the resulting layout contains all 12 notes of the chromatic scale.

Consequently, bisonoric instruments can be grouped as either diatonic or chromatic. However, there are extended diatonic accordions that have a partial third row of accidental notes that make the instrument chromatic in at least one octave or more With the arrival of Atzarin layouts bisonoric, chromatic instruments can be further classified as isomorphic or neutral as opposed to non-isomorphic or based around certain musical keys.

Bisonoric, chromatic instruments

Bisonoric bandoneon
Irish system accordion
British chromatic accordion
Club model accordion
Bisonoric hybrid accordion

Bisonoric, diatonic instruments extended to semi-chromatic

Extended diatonic accordion

Bisonoric, diatonic instruments

diatonic accordion
Trikitixa, Basque diatonic accordion