dr5 means the dynamic range is a 5. A dynamic album can go up to 15. Bad ones are usually 7 or below. Bad mastering is the worst plague on music presently, even worse than bad music itself.
this
it basically means the dynamics have been crushed so much that nothing has any impact any more. the music turns into a continous noisy carpet of sound where the softest clean guitar note is the same volume as a thundering bass drum or crash cymbal, everything is fatiguing and terrible, bass response suffers greatly, the mix turns into mud, transients disappear, and the waveform looks like ███████████████████████████████
i'm not trying to be a snob or anything but i can literally not listen to most music (especially metal) that gets released these days because it all sounds really, really, really terrible to a point where i can't get through full songs
the best thing is all of this destruction of music is done for absolutely no reason; it is objectively worse and destructive in every way compared to keeping some semblance of dynamics, but like so much else in the world, the objectively wrong thing keeps on being done and done again anyway because "that's what everyone else does"
some day we will look back on 2000-2015 or so and cringe so fucking hard at how we completely ruined our music
and they will re-release all these albums in versions made from dynamic masters and get y'all to pay $15 each for them again
currently, the only cure for the disease if you absolutely want to buy modern metal albums is to get vinyl, because it's physically impossible to make masters THAT bad and have them even function right mechanically on vinyl discs
and this right here is why people think vinyl sounds better
not because of any inherent superiority in the format -- in fact, cd is objectively better than vinyl -- but because vinyl masters are far less destroyed out of necessity