Unlike in a recording studio, live sound has a much greater dynamic range compared to a standard recording. A record is processed during mastering so nothing overloads those delicate grooves. A dynamic range horror story.
Live sound is less processed.
This is one of the main advantages of seeing a band live. When done properly, live sound is much more dynamic because you're hearing all the peaks that are taken away in the record and radio process. That is the one aspect of live sound that has always kept it artistcally creative for me - using dynamics in a way to create a pleasing flow from one section of a song to another, like bringing down certain parts of the rhythm section in the first verse so nothing crowds that precious lead vocal when it is first heard. Then bring the rhythm section back up for the chorus. As well, your standard solos or tags are always featured with a boost in volume.