When it comes to comparing live sound to studio audio engineering there are many things that highlight the differences between them. The consoles might look or function differently, the speakers used are different, the preferred microphones and placement might be different. The acoustics are different, and the amount of time you have to mix a product are different. But all of those differences really just bring into focus one major difference between the two worlds that sums up all of the other differences and overrules everything about doing live sound versus doing studio work. That main difference is variance.
In a studio environment the name of the game is control. Control the room acoustics. Control the mic placement. Control the bleed from other mics. At every stage of a studio environment you’re trying to control the inputs to make the outcome as predictable as possible and as easy to mix and master as possible.
Studios spend significant time and money perfecting the acoustics, positioning performers and microphones, selecting microphones and signal chain elements to optimize every step of the recording process. You have the same rooms, same mics, same techniques for isolation. As much as possible you’re trying to control all the variables.
Live sound is the opposite in many ways. About the only control you have is over what equipment you use, and sometimes you can’t even control that.
Variance is the name of the game in live sound.
You may be going from venue to venue, different places every gig. You get different acoustics, different times of day, different weather conditions, sometimes different performers night to night.
There is so much variation that attempting to control all the variables becomes nearly impossible. Variation in performers, variation in how those performers perform from night to night, variations in how the monitors affect the sound at front of house, and sometimes even variations in what equipment you use from gig to gig.
All of the comparisons and differences between the two really come down to that one thing. Predicability vs volatility. Control vs variance.
Ultimately that is the difference, and all of the various specificities of working in one world or the other can be summed up by that one word: variance. How much variation there is in the day-to-day work is the main differentiator in how that work gets done.