I bought this CD from a music store, i extracted the audio with EAC to wav and analyzed the tracks
 
some of them have full sound and some are like this, specially the ones from 1995 and below
 

 
the ones from 2000+ or 2005+ are 22.1 but have full sound on them, others like this one have these kind of spectrograms.
 
 
is this bad mastering? or is this a fake cd? the cd seems okay, it was sealed and uses a cd from factory and all.
 
 
I doubt i can get the same music on other cds because this is too obscure that is not even on the internet, so any thoughts?

Who is the artist and what is the album called?
 
If the album really is that rare, maybe just be happy finding the CD versions of the songs.

likely just a bad cd unless it is very rare as stated above...