Four FM

Mac OS X editor for Yamaha DX27 and DX100

Four FM is a Mac OS X editor for the Yamaha DX27 and DX100 4 operator FM synths. You should be able to use the editor with the DX21, although some DX21 specific parameters are missing.


This is a free program issued without warranty or a commitment to future maintenance. But, feel free to contact me with bug reports or if you want to help with beta-testing.


Mac OS X 10.6.x and later


The latest version of Four FM is 1.0.1(6)


  • Midi interface and channel settings are accessed through the Preferences menu.
  • Don’t forget to use Note Off after using Note On, otherwise you’ll get hanging notes.
  • Many parameter changes are only audible when a new note is played.
  • Init Voice resets all voice parameters to their default initialized values.
  • Get 1 Voice gets the current voice edit buffer from the DX.
  • Changes made in the editor are sent immediately to the DX.
  • Move sliders or press buttons on the DX’s front panel and see the editor reflect the changes.


Download Four FM here

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