Dumb question about FM synthesis: is it commutative, so that modulating a sine with a square is equivalent to modulating a square with a sine? I'm guessing it's an emphatic no, but my math is rusty and I don't have a DX7 handy to construct test-cases with.
I've been trying to wrap my head around exactly how it works, the better to use it, and reading the (oddly entertaining) guide to doing this on the C4. It's only implemented for sine waves; fine, but then I realised I can feed the instrument into input 1, generate a square (or more interesting) waveform on output 1, then use a patch-cable to feed that into input 2 as the modulator.
Hence the dumb question