Most interested in having the ability to play .midi, .mod, .it, .s3 and whatever the new ones are.
The best thing about these is that they do not require moderation and the filesize is tiny.
FMOD already supports these so all you have to do is literally change the filter in front of what bitstreams FMOD will load.
You don’t even need to do that; just allow uploading them to the site. (The client can already play these formats and I’ve tested this)
I’d totally be down for allowing tracker formats though. MIDI may be a little harder since ROBLOX would have to write their own synthesizer (to make sure it’s always the same across platforms) but otherwise this would be an easy change.
Well MIDI is the one I care least about since, at least the last time I used MIDI in 1999, there is no standard sound sample palette across systems. I only included it because it is by far the most popular format and the easiest to find.
Yeah. MOD/XM is probably the most popular tracker format, followed by IT and then S3M - but there are a few others.
If I were to prioritise one, it would probably be XM because it’s pretty well-featured and can do a lot of the stuff that most of the other formats can. That, and I’d be able to upload a bunch of stuff:
MIDI is still widely used today, Logic Pro X uses MIDI as a core element and that’s a really recent program. I work with MIDI’s a lot and they are by no means outdated. There are even various places to buy MIDI’s for you to play with or use
They still don’t sound the same across devices.
True but still allows you to very easily modify the song with ease
Tracker formats are like MIDIs, but far superior as you can define your own waveforms (short waveforms) and can also do really powerful stuff, like panning.
This is what a tracker format basically looks like in a human-friendly way, using ModPlug tracker:
Compare this with something like Renoise:
The general business part looks basically the same, and anything that can be put in a MIDI file can basically be put in a tracker file, assuming you have the right waveforms.
If you really like your midi composition, you can render it to mp3/ogg and upload that… Won’t depend on the users system’s sound palette at least 
In all seriousness though, I’ve heard that we’re upping the 2 minute sound limit soon so this may also be in the works.
Trying to avoid the 4MB download for a song on mobile.
Ah, Tracker music. The last game to have tracker music that I remember was Deus Ex from 2001…
You can still do some pretty amazing stuff with it, so I wouldn’t mind if it made a comeback 
