FM channel 3 special mode

[denjhang]

It can split channel 3 into two 2-op FM channels(one in made up from operators 1 &2, second is operators 3 &4).
My idea is that using this special mode, the third FM channel can be decomposed into two 2op channels, so that opn2 has a total of seven FM channels. However, some FM instruments are not allowed to do this because they will make incorrect sounds. Therefore, it is suggested to add a label when defining the timbre in WOPN, so as to distinguish whether the FM third channel special mode can be used. That is, only the voice of 2op can be used in special mode.
Although there will be some troubles in doing so, it can make full use of opn2.

[denjhang]

From six 4OP FM channels to five 4OP FM channels+two 2OP FM channels, Or use other combinations, I think it depends on the definition of FM Instruments.

[freq-mod]

For that, problem is like with (AD)PCM and PSG - even in WOPN ver3 draft there isn't any definition for FM3ch flag. So, first, bank format would have to be vastly updated, same with bank editor...