Sonic & Knuckles credits and title themes SMPS2MID trouble

[GamingGardevoir]

I want to rip the Credits Theme and Title theme from Sonic 3 & Knuckles with SMPS2MID, but they keep saying "Invalid number of channels". I saw a post from Valley Bell saying to get the music files from his SMPS Research Pack, but they are .s3k files and SMPS2MID won't read them.

[ValleyBell]

If you load raw, binary SMPS files (regardless of their extension), you need to set the "Z80 Mem Base" value correctly.
It needs to be set to the address that the Z80 sound CPU sees the song at. (which is the plain address in the ROM, because the Z80 can only see 32 KB parts of the ROM at once)

In case of S&K, you can get that one from the Sonic Community Hacking Guide.

[GamingGardevoir]

If you load raw, binary SMPS files (regardless of their extension), you need to set the "Z80 Mem Base" value correctly.

You say “regardless of extension”, but SMPS2MID refuses to see the files that aren’t .bin .sms or .32x; does this mean I can change the extension from .s3k to .bin and it will work correctly (assuming I put in the proper Mem Base value)?

[ValleyBell]

You can *always* force the file open dialog to see arbitrary files by entering a file mask with wildcards as a file name and pressing Return.
But yes, you could also just rename it to .bin.

By now, file extensions for SMPS files are mostly intended for users to easily identify the variant of the format. (This used to be different with SMPSPlay v1, but since v2 the file extension doesn't matter at all anymore.)