I'm glad to hear from Ivan and Ted that there are shows that aren't just about level.
Here are what I consider "good guidelines" for levels at EDM type events. Yes it can vary depending on a number of factors.
This is assuming a system that is truly flat to around 25Hz and has reasonable HF extension to 12-14KHz.
Around 100' away, 102-104 A slow and 125-130dB C fast is what you would measure on a simple SPL meter.
When designing a system, the peak SPL should be at least 10dB greater than those numbers. 15-20dB would be a better target, due to the abuse that these shows that often run non stop for 72 hours can do to a system in terms of heat build up.
It is a good idea to set thermal limiters at 1/4 continuous power.