Sheet music reader. I use ForScore. I have set it up to send a Midi signal to my Korg Pa900 to select the appropriate Songbook entry which means I can choose a song in ForScore and be ready to play it immediately!
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Graham, Korg Pa1000, Korg G1 Air, Countryman E6, Roland BA330, 2 x Roland CM-30, , Mackie SRM150