Ok. I was wrong. vgmstream supports musx version 10, but not its "PC" version. So the easiest way would be:
1. change 32-bit value at 0x34 to 00 (no loop)
2. change "PC__" at 0x10 to "PS3_" (to make it think its PS3)
3. rename file to .musx
Now vgmstream can decode it with constant samplerate 44100. Change it if needed.
The problem is that vgmstream doesn't work with sound banks at all. So if you want them, you need to write your own decoder, or use this workaround:
1. do steps 1-3 as before.
2. change byte at 0x800 to anything else. (that will make vgmstream think its not a bank)
Now vgmstream can decode it as one big single file. There will be glitches at the beginning of every sound, big static at the beginning (big table of all sounds), and in place of the sounds that are uncompressed plain PCM (like the extractor fan sound you heard already before).
I'll do my best. I'm a noob at vgmstream. Did you just use a hexeditor to change those values? Also, how did you specifically find that one song? Was their a certain numerical bunch that was music, or is it just jumbled up. That song is very early on in the game.