Reverb using World Settings option

Has anyone had any luck getting the Reverb effects that you can apply in the World Settings tab of a level in 5.X?

Reverb works as expected when using an audio volume, my problem is that I have a procedurally generated map which ahead of time I do not know the bounds of and aside from setting the bounds of the Audio Volume to some ridiculous amount, I cannot get full coverage.

From the looks of it, the World Settings audio reverb should allow me to do the same thing as the Audio Volume, but globally, no? No matter what volumes, fade times or Reverb Effect assets I select, I get nothing out of it.

Any tips or hints would be greatly appreciated.