Is the recording entity I am referring too.
I have two digital copies of this song, and they generate two fingerprints. They are audibly the same (a studio recording) but one appears to be subject to the “loudness war” effect.
As you can see the spectrum difference in the above screenshot.
So my question, if the song is “louder” is that a new recording or same recording?
i’ve been having this same dilemma… in my case, there are two recordings which are definitely the same, except in one of them there are insane amounts of clipping. on some headphones it’s borderline unlistenable, but on others it’s mostly fine. i kept those separate, but i think if the difference in loudness isn’t so drastic that the loud one has audio issues because of it, they can probably be considered a mastering difference & therefore the same recording
Same recording, it is just “remastered”.
Neato, i will add an annotation to that effect 
I agree, if the recording has audible artefacts in it (clips, pops, wow, flutter, rumble, hum etc.) then it would be a different recording
In MB terms the focus is on the master tape that came out of the studio. Even if clicks and pops have been removed - this is still the same recording. Cleaned up remasters are still same Recording as it came from that same original tape.
If it has been spliced and diced and new bits added or taken out, that is a new Recording.
whats the idea on really bad transfers?
As a man of delectable taste in budget compilations, I can attest that some of them seem to like to transfer old recordings from dirty shellacs, wobbly tapes or from an AM radio down a well.
Would they be new recordings? (I of course annotate these when I encounter them)
Bad transfers are still same Recording.
We know that in our own collections we have some albums that sound better. Sometimes a remastered one. Or the one with that odd tape hiss and crackles removed. To our ears we know which we want to listen to and keep them apart.
MB will treat these all as the same Recording. MB only cares about that original master tape from the studio. The one the Artist recorded. Its not about the journey it has been on after that through different quality of production, remastering, volume changes, crackle removing, 25th anniversary remaster. That does not make a new Recording in MB.
Good to know!
I will still annotate if a fingerprint is particularly stinky in its quality 
This is one of the reasons you see multiple fingerprints connected to a Recording. And that kind of extra note often appears and is useful to see for us geeks 
.
There is a similar thing with those people who like the ISRC numbers. Original Release, Compilations, Remasters all get different numbers attached. To MB that is not relevant as the Source Recording is the item that is important.
I also agree with you that some compilations can be awful and really don’t care about the audio quality. It is why so many of my CDs come from fishing for older releases on EBay.
Quality don’t count to these guys. Just the cash. Low quality CDs, cheap and fast production, junk source tapes. And as your image shows - turn the volume up was a trend for a while.
Compilation makers really don’t care about the music. They never listen to it. Just bash another one out and move on to the next dollar. 
Junk mastering is not a reason to keep them separate. I’d just annotate the release which is badly mastered, but the recordings are the same tape from the studio, and should be merged.
And I know what you mean about decent headphones vs those weedy things that come with iPods. This is how the companies making the bad compilations get away with it. They expect people to be listening to badly compressed MP3s on cheap headphones.
fair enough, i’ll probably end up merging them. it’s just so bad at some points that it’s hard to prove the awful crackling sounds aren’t a stylistic mixing choice 
Maybe the guy doing the mixing was being all trendy and cool and just holding one half of his headphones up to his one ear. Or plain tone deaf. 
