Bandoneón

The Bandonion is the namesake of Heinrich Band, who altered the layout of the German Concertina (Konzertina), trying to make it work better for classical music and the popular music of his day (whereas the Konzertina was geared more towards folk music).

It usually has multiple reeds for each note, most commonly tuned an octave apart. Over the years, Band expanded the instrument to extend its range, keeping the core key layout intact and adding additional buttons. It is especially popular in Argentina, where it was introduced by central European immigrants and was incorporated into Tango orchestras. In Tango literature it is usually given the spanish spelling "Bandone&oacute;n."

Some German instruments have the keyboard arranged in the Einheitsbandonion layout, which was meant as a standardisation, but was never adopted by Tango players.

A unisonoric, chromatic version of the instrument was also developed in France for players who didn't want to learn the complicated keyboard.