Free patch editor works on Linux, Mac & Windows
и не только для FM
https://github.com/eclab/edisyn
Alesis D4 and DM5
Casio CZ Series (CZ101, CZ1000, CZ3000, CZ5000, CZ-1)
DSI Prophet '08
E-Mu Morpheus and Ultraproteus (Single, Hyperpreset, and MidiMap modes)
E-Mu Proteus 1, 1XR, 2, 2XR, 3, 3XR...