Recording and mixing musical instruments and vocals offers the musician hundreds of sound colours by way of DAW plug-ins. One of the most-loved effects for guitarists is the delay. (or echo)
Hank Marvin of the Shadows crafted a whole new sound in the late fifties and early sixties with his mix of short and long delays set to repeat as they faded. Because Hank was using the old technology of tape-based delays there were imperfections that we know in retrospect actually added to, and became an inherent part of Hanks sound. Wow and flutter (minor speed variations) introduced by the tape passing around the heads created subtle pitch variations that added a mystique, and depth to the echoes. Also, the recycled delays lost sonic detail with each repeat, resulting in varying degrees of distortion as the echoes faded.
Some reverberation would often be added to the delayed signal, and this raises the question; what’s the difference between the two popular effects, delay and reverb.
Delayed echo is made up of single or multiple repeats of the original signal. The delayed repeats are audible since they are usually delayed by 50ms to 250ms from the original signal. A percussive signal such as Hank’s muted string technique makes it easy to hear these discreet repeats.
Sound perspective: It is important to realise that with delay effects alone, the listener hears the audio perspective as if the sound is being generated from fairly close to the listener, but with these big echoes coming in from behind. On the other hand if you were to add only reverb (without delays) the effect is to offer a more distant perspective. This is useful when wanting to push backing vocals or supporting choir in an illusionary space behind the soloist. Too much reverb on the soloist will lose the intimacy (closeness) of the performer.
Summary: Delay will add a “halo” effect behind the instrument, whilst retaining a predominantly intimate closeness. Reverberation will allow the sound engineer to place the instrument farther back in space.
Tip: In order to add reverb without losing intimacy just put a delay of 50ms to 150ms before feeding the signal to a reverb device! This is called Pre-delay and is usually available as part of modern digital reverb devices and plug-ins.