Decryption Help

[Pingus!]

This may sound a little difficult, but here it goes.

I am here to ask how to even start. I see people taking audio files from really any game, with the most unknown file type possible, but turn it into a wav or whatever. My question is, how do they do it? I know they use mostly Hex Editors and what not to remove the encryption, but how?
How do they just spot the encryption and delete it? Is it mostly trial and error? As far as I know they try to remove byte by byte and hope they get the results they want. And in the Hex editors with all those random variables, how do they know which ones to delete? Same with the byte removers, I want to know how those really work so I can try to figure out myself.

All I'm asking if for some clarification. If you don't feel like answering any question here or related to these just hook me up with a video or something to give a full tutorial on how it's done. I'm just a person who wants to learn.



-Thanks in advance,

Well first off, I would start off by getting a gba rom, and see if you can mess with the settings in game to turn off music and leave SFX on. Then, try audio recording and playing the game and creating the sounds by moving etc. pull that mp3 sample into audacity and take out the sound effects. Put them into different files, save, and there you go. Try this program and tutorial:
http://www.vg-resource.com/thread-21591.html

Any questions feel free to PM me, Welcome & Happy Ripping!
~Anex