The individual explosion sounds are all playing on the caster directly, and not where the explosions actually occur. This means you cannot hear the explosions at all if you don't see the caster, even when you can clearly see them hit areas you have vision over. If you are damaged by Diabolic Edict, you cannot hear it at all if you do not see the caster.

The explosion sounds should play where the explosions happen, not where the caster stands.

PS: Crystal Maiden's Freezing Field has the same issue. The sound of the ice shards hitting the ground are all centered on CM, instead of playing where the shards land.