This happens when you get beyond, (as in behind) the front of house PA) You are hearing stage volume for the most part. Maybe some monitor, but doubtful. If you walk back a bit from the stage, you can hear what the sound man is going for and how he/she wants the band to sound.
I get this all the time at shows. Sometimes stage volume is so high, that the sound person hardly mixes the offenders into the mix at all. **See YOB at Hellfest**
https://www.youtube.com/watch?v=6d4fKpnafhM They don't normally sound like that. But from what I know. The on stage volume was high for guitar. So the mix, taken from the board, sounds SUPER bass heavy. Because the guitars hardly needed anything to bring the total volume to where it sounded good to people's ears.
Yes. HOF are loud. Those straight 16th note double bass beats started to feel like a jackhammer. I haven't heard EW live yet. I am a big fan of the genre. I do like bands that use dynamics though and not just play at 11 all the time. Check out Mars Red Sky,
https://www.youtube.com/watch?v=2uyxZZTodsE or White Orange,
https://www.youtube.com/watch?v=EfSMuXH2-uU Both are a bit more psychedelic sounding doom, but really cool.
Loudest show that I have been to was back in 1991. Clash of the Titans tour in Lakeland FL. Slayer, Megadeth, Anthrax, AIC. Slayer recorded half of their Decade of Aggression there. It just kept getting louder as the night went on. The last band was Megadeth, and by then, the sound was terrible. Hell, it already has the horrible acoustics of a big metal box coliseum. You couldn't even tell what songs they were playing till they were almost done with them. I don't mind loud, but that was ridiculous. But, I suppose, that's metal for ya.