Hello, i know there are audio cartridges existence like:
FM-PAC / FM-PAK = MSX-Music (OPLL)
Works with (games):
Almost all MSX2/2+/turboR games produced after 1988
Almost all demos/disk magazines/music disks e.g. made after 1990
Music Module = MSX-Audio (OPL(1)-compatible)
Works with (games):
Most of the Disc Stations by Compile
Some Compile Games
Moonsound =(OPL4)
Works with (games):
Sunrise Games?
I´m looking a music hardware cartidge that allows combine SCC or PSG adding new channels of sound meanwhile SCC or PSG are working, i think all above cartidges cant works for SCC music (adding more channels) and i think above sound cartidges work with PSG according if that specific PSG game is compatible or not with it. In msx i prefer Konami games, for example if i play Vampire Killer original sound is PSG (the only way to get PSG "sounds better" in this case will be use "PSG to SCC" conversion util from Playsoniq, i only knows this for PSG), if i play Metal Gear the game is SCC and i dont know how could i get more channels or combine someway with another sound cartidge to best audio experience using SCC... willñ be possible combine 2 SCC working in only one game?
If you know any way to improve SCC or PSG sound in-gaming please tell me about it...
Thanks a lot.

, i´m wondering if "PSG to SCC" Playsoniq util will be someday "SCC to OPL4"
, see and ear this video that i found (note the video is not real, is a edited video with SCC Space Manbow sound edited to OPL4, or something like that):