Turok GB stereo separation - emulation vs hardware by radornkeldam at 8:44 PM EDT on April 21, 2019
This is a little convoluted, but I'll try to go to the point.
I like the GameBoy Turok soundtracks. Reading an interview with the composer some years ago (which I can't seem to find again), something was said about Turok 2's music lacking stereo effects even though it was composed with them, because someone didn't configure the sound engine properly, so everything sounds in both channels. This got me thinking that, if the music data still contains the stereo information, assuming the compilation didn't hardwire it to mono, perhaps the ROM, or even the GBS could be hacked to get the stereo effects back.
Regardless of that, reading on this story this made me curious about stereo effects in other games of the series, listening to the GBSs, and that's where I started having unpleasant surprises.
This is supposed to be an unadultered hardware recording of GB Turok 1. There are mp3 and flac links in the description. Not mine. https://www.youtube.com/playlist?list=PLF369B4981FD2E272
In this recording, there are many clear stereo effects and panning, and they are richer and more complex than merely remixing the chip's channels to go to different side, so I don't think it's one of these pseudo-stereo "remasters".
When playing the GBS rip or even the full game in an emulator (BGB, mGBA), as I don't have the cartridge, most of that is completely lost and only some things here and there remain, usually hardly noticeable.
It would seem gb sound emulation is not accurate enough yet? Is this known to happen in other GB games?
In case someone wants to try listening from the game, there's a level select, but gamefaqs has the cheat wrong, even though I sent them a correction ages ago. The correct way is, in the title screen, highlight the "OPTIONS" item and then press and hold UP, which will highlight the "START" item. Without letting go of UP press START.
Bumping this old thread to say that I've fixed this issue, after someone else pointed out that a few early Alberto Gonzalez GBS files were found to be entirely mono despite the games themselves being stereo.
The culprit? The music driver used by Bit Managers uses a flag to determine whether music is to be played in mono or stereo. The majority of the GBS rips ignore this flag, so some of those play in mono despite the game itself having Stereo audio (Asterix and The Smurfs). Moreover, some of the games (Turok 1 & 2 being the most obvious) don't set the flag either - far as I can tell there is no way to get these to play in Stereo.
The game Asterix has an options menu which allows you to turn stereo on or off which made it easy to identify the appropriate memory address. From there, it was trivial to find the piece of code which checked the flag. I searched through the entire gbs.joshw.info and modland GBS archives, and found 25 rips which use this same code, and of those, identified 9 soundtracks (11 rips EDIT: correction, 10* rips) where setting this flag recovered missing stereo panning. These patched rips have been submitted.
I'm also working through identifying and patching the cases where the game itself doesn't set this flag. Turok 1 & 2 are done, and will be both up on soon RHDN: https://www.romhacking.net/hacks/7836/ Smurfs Nightmare and Tintin in Tibet have the issue as well. I'm still working through the others.
That still leaves the mystery of how bucky / explod2a03 got a stereo recording of Turok 1. I know his usual method was running the GBS file through GBS2GB using a flash cart to play tracks on hardware. Perhaps at some point there was another rip of Turok that circulated that also patched the bug? Or maybe something with that process fixed it? I doubt he remembers, and I'm sure if there was anything special in the process he would have noted it in the youtube description or comments. I'll ask the next time we chat.
EDIT: As I was working through the games themselves, I found that Asterix and Obelix for GBC *doesn't* need the fix as it sets itself to stereo on boot. The GBS file for that version is already correct as well. The differences are pretty subtle in that soundtrack - the only stereo part is a tiny echo part that last 15 seconds in a single song. Easy to overlook.
edited 10:51 AM EDT June 5, 2023
Turok GB stereo separation - emulation vs hardware by Newbie2000 at 11:37 PM EDT on June 15, 2023
Can you list the corrected soundtracks? I noticed much improvement with the patched Turok games in stereo from the patches at romhackng.net. I hope to listen to the patched GBS files soon.
Not all the games themselves need patching - some of them set the value correctly on boot up. I’ve been meaning to circle back and make patches for the remaining games but I’ve been sidetracked with other projects.