What the heck is that? Well, this applies nearly only in outdoor situations. Very common (not to speak: essential) when setting up huge events, this technique is barely used in smaller events, mostly by lack of equipment. Here’s the situation: you play an outdoor event and you use your own PA. The place is big, more than 50 meters between the “backrows” and the stage. You have a nice PA, but that far away your sound becomes blurry and undefined, and not powerfum enough. You decide to set up a pair of speakers at approx 34 meters from the stage, and feed your main mix to these to enhance the listening experience for those in the back. The problem is: sound travels through air at 340 meters/second, electricity at the speed of light. In other words, the sound from you main PA will fall behind the sound of the remote speakers by 100ms. We musicians know what that means, in terms of latency: a nice slapback echo. The trick is to delay the sound you send to the remote speakers by 100ms. (Note: these numbers are approximate: the speed of sound varies with temperature and some other factors: soundengineers measure the exact delay by sending an impulse through the main PA and catch it at the remote location with a measuring device (either you use a laptop with appropriate software like SMAART Live or Spectralab, or you use a hardware device such as the Minilyser from Neutrik). But well, up to you to get it right by trial and error if you don’t have access to this kind of equipment). Of course you’ve already figured out by now how to set this up:

Diagram5

Any basic stereo delay will do, (set the feedback at 0 and disable all sorts of filters and other goodies!!), but I recommend the Audio Delay plugin from Voxengo, which is perfect for this usage, and free! Way back when (not such a long time ago) hardware units that were able to delay stereo that much with impeccable quality were highly expensive (well, ok, some had temperature sensors and stuff like that and could react on environmental changes) but well, isn’t it nice to be able to do this ourselves with (near) zero additional budget??

DelayStack