What

Only because of the device it was recorded on. Just some phone, I expect, hence the "patchy" quality and the crowd being louder, since where this person recorded is part of the crowd, so it picked up the crowd noise more since it isnt closer to the stage and a basic phone doesn't have the equipment (not the word I'm looking for, but I hope you get my point) to "mute" the crowd and enhance the actual music being played. Besides this is a big venue, so reverb also has a HUGE part to play in why the crowd is louder at some points than the music lol. Hope this makes sense

Actually in person the crowd was really louder :)

Makes sense thanks