i perfectly agree with u about arenas and this is because the sound arrives directly e clearly to the spectator. Bands like the prodigy, who have a particular strong and mixed sound, need to play in open spaces as arenas, because in close space as covered stadiums or sport palaces the sound results like "cozy" and it doesn't give the hundred percent of its potential. And then, especially, in the arena the sound comes from the low to the high, that is simply perfect.
Soory I didn't want to seem a technician professor,
but i think that such aspects are important to be considered in a live context.