Sorry, but I don't understand you because my english is bad. Normally I've 48000 Hz and now I made 49716 Hz but with compat the 8th wave form (Derived Square) sounds equally wrong.
And sorry, but I can't write something for some program.
I've a Soundcard with a real OPTi-Chip. I posted it also for comparing. Here you can hear the difference.
X00 (Channel 4)
And at the song "The absence of Julia" I heared, that one instrument with default at some pitches makes undesirable high noise what doesn't happen with compat, but there is a problem. I've a Soundcard with a real OPTi-Chip and I heared, that normally this high noise comes only sometimes (not ever and not never). Which of both is right? I think nothing (or possibly the sound of default).
The absence of Julia (Channel 1)
I'm not sure, but if here are 4OP-instruments you can hear how default works wrong with it and with errors nobody can wokrs correctly with Adlib Tracker II if he want to have 4OP-instruments in the song.
Cybersphere BGM 1
If you play a song with 4OP-instruments with ADT2PLAY and default, after 1st playing the oplemu will lose the connection of both instruments if you don't start new the oplemu (with "oplemu=..." or "oplmode=...".
4OP-TEST with default
And now the last problem which I know. With OPL2 some OPL2-songs can will played with the 1st wave form (Sine) only, even though other wave forms are choosed. Only with DualOPL2 and OPL3 all OPL2-songs can will played with other wave forms. I don't know why but it's so.
The problem is that default with OPL3 is like as OPL2. Some OPL2-songs can will played with the 1st wave form only. In this example one instrument is carrier = 4th wave form (Pulse-Sine) and modulator = 3rd wave form (Abs-Sine) and if it will played with OPL2 it sounds as would be both 1st wave form (Sine).
SUPAPLEX with OPL3
default (as OPL2)
compat (as DualOPL2)
Sorry, but I can't explain it better.