DX21 Voice compatibility

The DX21 uses the same 4-operator, 8-algorithm FM synthesis as the DX27, DX27S, DX100 and TX81Z models, therefore voice data can be transmitted and received between them.

NOTE: The TX81Z has a number of features that the DX21 does not. When tranferring data between these two instruments some voices will not sound exactly the same and some parameters will be ignored.