Patch Base has the best Yamaha DX7II editor and librarian available for Mac and iPad. Edit any parameter, organize patches, create random patches, and more.
You don't have to be a wizard to program FM sounds. You just need good controls. Patch Base makes FM easy to work with by showing you the layout of the currently selected algorithm and the envelopes and settings of each operator. You can finally visualize what's going on inside of the DX7ii, and once you do, it's not that complicated.
Patch Base's Bank Editor let you change and organize the saved sounds on your DX7ii. You can easily save a bank to a file for back up and storage, and import entire new banks in seconds.