What is delay fill?

Question:

What is delay fill?

This one is for all of the audiophiles out there. What is the purpose of processors that produce speaker delays? Why would you want to purposely delay a signal? Is this for when multiple speaker clusters are used away from center stage and the delay is inserted to compensate for the inevitable doppler effect? If so, how? I'm kinda curious.....

Best Answer - Chosen by Asker: If you are at a outdoor rock concert, you'd put a set of "delay fill" speakers away from the main stage (like a set of secondary or supporting speakers) that have a small delay to account for distance to serve the crowd.