A lot of new instrument types were added in 1.12 and the InstrumentTypes enumeration should be updated.
http://minecraft.gamepedia.com/Note_Block
https://github.com/SpongePowered/SpongeAPI/blob/bleeding/src/main/java/org/spongepowered/api/data/type/InstrumentTypes.java
Along with this I think it would be good to add an InstrumentTypeProperty for blocks to show-case what kind of instrument type they are that note-blocks use.
I am currently working on this, also implementing InstrumentTypes in general.
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Along with this I think it would be good to add an
InstrumentTypePropertyfor blocks to show-case what kind of instrument type they are that note-blocks use.