Nintendo DS music creation

[Spectremint]

I had a game idea recently that I wanted to go through with, and part of my idea is to make the game look and sound similar to Nintendo DS games, low-poly-ness and all (but it's a game for modern platforms). My question is, how the heck do you make NDS music? I know there's no definitive "thing" for NDS music since there's so many sound fonts out there and there's also streamed music, but I'm talking about the former: the MIDI-esque, seemingly tracked music found in most DS games, especially early ones.

 

[NotImpLife]

You can use a tracker to create music in .MOD format, playable on the DS using the MaxMod library. MilkyTracker or OpenMPT are some options I know. There is a bunch of tutorials out there for using the trackers. You may need samples for your instruments, which you can create by yourself via adjusting frequencies, or download from MOD-dedicated websites. If you are up to making a real NDS game that can play your music and not a DS-like game running on other platforms, I recommend looking for all the possible information you can find about sound on DS (e.g. use 8-bit samples, number of possible channels etc). I have myself to dig deeper into this matter too, so I hope sharing all I know with you will get you to some kind of starting point in your own journey

 

[FAST6191]

As above and as you say the DS was fairly arbitrary and software defined in its approaches. I don't think anybody has ever analysed the sdat banks/sbnk files to see if they share a commonality (the megadrive was also pretty arbitrary if it wanted to be but enough was shared that it has a bit of a signature, usually it being a bit tinnier and no bass compared to the SNES which was largely unjustified, albeit most things that people know if asked to make a list colouring way outside the lines). Number of channels (all of which were wave capable, so not like the GBA where that was more limited and some might have been tone/noise channels and not much else) and sample rates available mean it is largely straight software as far as most purposes are concerned. http://problemkaputt.de/gbatek.htm#dssound has a bit but it is not as nice as some of the GBA stuff like http://belogic.com/gba/

The DS DAC left a lot to be desired so it does have a bit of a fuzz going on, even more so if the bitrates and sample rates were crushed for... I am guessing space reasons (don't think it was CPU reasons, and SDAT files are usually the larger component of a given game) and most things I have ever looked at normalised as a matter of course rather than mixing levels "properly".
About the only thing I would note is actually in some ways it is a simpler device than many older chips -- play with some old stuff/visit HCS64 and whatever is doing the foobar plugins these days for game formats and you will see people discuss multiple decays and rates thereof and how a given plugin/emulator/seemingly the likes of the analogue pocket if their changelogs are anything to go by are improperly implementing them, though this is likely obviated by the wave samples that things tended to use able to dodge that.
The DS SDAT timing is technically inaccurate but not in a notable way for most purposes that are not trying to invert things to cancel audio (no 64 time technical death metal or "it was done that way to sound like a garage band without a click track" type deals) or sync multiple streams. It is a bit more limited so you can not go crazy crazy polyphonic right off the bat like some of the excesses with modern PC based trackers but even without wave based samples themselves being layered to dodge that you are still going to be able to make things nobody is really going to be able to ear transcribe if you wanted to go there.

Indeed the DAC might be such a part of the DS that it might be easier to create something on the DS and export that -- loads of great music homebrew and some commercial stuff exists.