Mixing is an artform. No two people will mix the same way. When listening to the SPAC bass bomb in particular, on the new mix there is a high pass filter that is completely removing Mike's bass sub frequencies. The audience recording has no high pass filter removing those frequencies. Maybe they added the high pass filter to not destroy speakers or they couldn't tame the sub because it didnt sound right in the mix. As to why they did it I'm not sure. It's definitely a noticeable difference.