Remasters - are they better? What exactly is it?

Ok so, when I'm flipping through Tidal and I see both albums, I'm usually/generally better off sticking to the original.  

I do wish we could take some older un-dynamic albums where things sound thin and add some oomph to them.  Like, cranking up the Beatles is usually not worth it.. No slam or low bass and drums sound like my play kit I had i the garage as a kid.

You can pretty much tell what decade something was recording by the quality of the recording.

There are plenty of examples of remasters that better earlier or original masterings. That includes remasters with DRs as good as or sometimes better than earlier versions. Remasters by engineers Hoffman and Gastwirt are the first that come to mind but there are plenty of others.

A bit of research will bear this out. Any new "older" CD I buy goes through a research process that includes remasterings, dynamic range and other factors that allow me to buy the best. Often the original releases are best. But often they are not.

@dtximages 

"un-dynamic" recordings aren't typically thought of as soiunding "thin". If anything because all vocals and instrumentation is more level-equalized it can have a "thicker" sound. 

As far as telling the decade of a recording by the quality, nope. Plenty of old recordings (last 40 years anyway) equal or better newer recordings, and the opposite is also true. How do I know? I have them in my collection.

The idea behind remastering is to take the original master tapes and get a better transfer to the tapes (analog) or files (digital) that are going to be used by the pressing plants to make LPs or CDs.

Many things can and often do go awry though. The wrong tapes are used (a later generation of tapes than the master tapes, etc., a little resolution is lost each time a tape is copied). The mastering engineer may decide to make changes to the sound, boost the bass a little, for example. Sometimes the tapes have degraded since the original mastering was done.

The biggest problem is that many remasters are overly compressed. Quieter sounds are made louder. Loud sounds are made so loud that the loudest peaks of sounds are chopped off. The dynamic range (the difference between the quietest and loudest parts of a song) is lessened. In the worst cases, once enjoyable albums are turned into one loud in-your-face endurance test. This is a oversimplification of remastering, maybe someone who knows more about the process can explain better.