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<http://schema.org/text>
"the anglo-german system is the same as most types of of German concertinas, chemnitzers bandonéons in the center if the keyboard.  \n \n\n\n\tThere is a logic to this system but bandoneóns and German concertinas are built with long rows of reeds fastened on the same plate inlike English concertinas where every pair of reed has an individual plate, so if you want  add notes you must add them in the extremities of the plate and you cannot change the middle part, the more you go in the treble and the bass the more you go on the outside of the keyboard.\n \n\n\n\t There is no more internal logic to these extensions, there is only a historical explanation.\n \n"
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