The music you linked doesn't sound bad but i have no idea how they should sound.
( what the musicians/producers accepted as the final sound/mix)
If you have a couple of CDs, there are surely some sounding really bad;
you know this by simply listen.
less dynamic range, distortion and clipping, thin, hollow and lifeless
because of high compression, or the "instruments" all blend together into distorted mush.
Loudness war is another example of bad mastering practices in the industry today,
though it's not the only one.A good, but lengthy explanation at:
There is no such thing as the correct/right sound...remember,every song/CD has been
put together/produced from various tracks recorded on various days, sent through a lot
of sound equipment and so on.
May be you hear the drums left, the guitar right and the singer in the middle in front of them,
In reality, (recording studio),It has never been like that.
Mostly every part has been recorded separately, many times, and then the best parts were put
together, add some "room".....
All in all it boils down to: ..."does it sound pleasing?"....
A not so bad recording: