how do you convert .fsb to something playable?

Downloaded the fsb extractor so I make the resulting files playable. Which are encoded in ADPCM and in a wave container.

If you just need to extract archive there is multiple tools for doing that, one of them:
http://aezay.site11.com/aezay/fsbextractor/
And this one tiny command line open source tool I use:
https://github.com/gdawg/fsbext

But actually you can edit those files using FMOD Ex Designer:
http://www.fmod.org/download/

Thank you, I will extract but they're not playable. just noticed a typo in my original post.

What do you mean as "not playable"?

I extracted both PA_Music.fsb and PA_SFX.fsb and all wav files are playable without any problem. Not sure if audio player I using available for Windows, but those WAVs also playable in VLC for example.

So most likely you just need to download proper audio player.

Also I can't convert them using converter built into VLC, but FFmpeg works just fine.
On Windows you can use this command line tool to convert files to Theora:
http://v2v.cc/~j/ffmpeg2theora/download.html

ADPCM, the audio format of Doom.
Took me ages to find a reliable way to extract ADPCM from .fsb and convert them in a way the music could be correctly played.
I'm not on my personal computer right now, so can't remember what i used to do so, but i'll check this evening an update my post.

I don't know why i can't edit my post...
Well, i remembered how i made to extract music from the .fsb, then convert the ADPCM to something else :
MusicPlayerEx.
Was easy to use and the result files were completly functionnal.
Then i used Audacity to rework the files a little and convert them to .aac.

Thank you guys for the help. Still can't get it to work.