Whether used in live mixing or for recordings, delays are differentiated by their two main tasks: as a dazzling, ear candy moment, or as a more subtle enhancement that surrounds the music in a spatial, three-dimensional environment. Deciding on what instruments/vocals get delay--and whether to go stereo or mono--depends on how you want the sounds to relate to the audience as point sources. "Point source" means the instrument or vocal occupies an exactly set pan position in your stereo mix with all its sound heard from that point only. Dry and present is best for a true point sound. Generally, snare and kick drums, bass instruments, and lead vocals all start out as point sources, and occupy a fixed center pan position. However, you can use a short stereo delay to spread these center-panned sources out across the speakers, giving them a wider sonic image without sounding as wet as if they were hosed down with reverb.
Here Are Five Delay Tricks That Can Energize Your House/Sound
(1) Delay For Slower Tempo Rock Tracks
A great old-school trick on slower rock tracks is to use a mono 16th-note delay on the bass drum mic to expand the sense of impact without obscuring the attack. Use very little of this effect without feedback (one repeat only), just enough to barely hear it because you only want to feel it. I sometimes roll off the top end of the effect return fader to obscure the second attack made by the delay.
(2) Compress The Delay Return
When using a longer mono slap on vocals or guitars, compress the delay return channel. The compressor props up the number of repeats you'll hear, and makes the effect more consistent, more present, and easier to control for live sound mixing.
(3) Stereo Delay
Stereo delay elevates and separates the lead vocalist from the band in ways not possible with EQ or compression and creates an aural "virtual stage" for the singer. Short stereo delay has a harder and dryer sounding ambience than reverb; so if you're stuck mixing in a very splashy live room, try stereo delay instead of reverb on lead vocals.
(4) Increase Size Without Reverb
For a feeling of increased size and more apparent vocal level, set up a stereo delay (or two mono delays) with the outputs panned hard left and right. Send the vocal signal equally to each channel with the left side delay set to 60ms and the right side set to 40 ms. (For faster tempos, shorten the times to 40ms and 30ms, respectively.) Use no feedback--this is a subtle effect to fill out the vocalist's sound and should be barely perceived. If you hear an actual slap (a distinct sound), either the delay is too loud or the delay time is too long.
(5) Shoot Across Delay
To get a "shoot across the room" effect, use the same setup as above, but pan both delay outputs hard right or hard left. Now pan the direct sound to the opposite side of where the delay is set. This keeps the source sound dry and present, but spreads it across the stereo field in an animated, musically dynamic way. A dry guitar sound, for example, would reside in the left speaker, and then echo a few milliseconds later in the right speaker.