Raymond Devos - La Marine in Concertina Videos & Music Posted April 7, 2018 ritonmousquetaire> Ah, I forgot to answer your other question. I think that on any instrument you have to play with your own limits and, unless you play electronic music, with the limits of your instrument. So I think that there is a lot to do with a 46 buttons hayden duet. But as I got used to 52 buttons I now need all these buttons and would be frustrated to have just 46. Actually I'd like to get even a little more buttons. With the hayden system you have all the "normal" notes in the middle of the keyboard and the flat and sharp notes on each opposite side of each hand, which is quite convenient to play in the most common keys but become more difficult when you want to play in some keys with many altered (?) notes. So I'd like to get the flat and sharp notes doubled (?) on each opposite side of each hand in order to have the choice of the fingerings when I have to play in those keys.