Delay is an effect that is generally used to create a sense of “space” for a guitar sound by imitating a sound reflecting off of a wall. This is not to be confused with its more complex cousin, reverb. It’s a pretty straightforward effect: have the original signal duplicated but delayed by a defined interval of time, usually measured in milliseconds. It’s a fairly easy effect to use so I’d like to focus a little more on the parameters and the different categories of delays that can be used.
The most important adjustable parameter is the delay time. The delay time is often sorted into four categories: doubling, slapback, echo, and loop. Doubling is the shortest amount of time, between 30-50ms. When delay times are this short, the delay signal is actually perceived as a single sound but with a sense of stereo separation (if it’s panned left and right); similar to a unison performance. Slapback is a a very short delay between 75-250ms, and creates a sound that’s reminiscent of a tiled room. This is a defining feature of Nashville recordings from a certain era, where vocals were often thickened with this type of delay. The echo effect, where it begins to sound like you’re playing into a mountain valley or cavern, is around 250ms-800ms. It creates a large and almost surreal sense of space, finding frequent uses in psychedelic styled music. Some artists set the echo time to a rhythmic unit of a song (the Edge from U2 likes to use a dotted eighth note value) to achieve an effect reminiscent of an arpeggiator. Once we get into delay times in the range of seconds, we enter the realm of looping. Looping is used to repeat and layer musical ideas to create a one-man orchestra performance. Outside of these typical uses, guitarists like Tom Morello (Rage Against the Machine) have made novel sounds by changing the delay time as he is playing.
The feedback control adjusts the amount of a delay signal that gets fed back into the delay signal path. The result is that you are able to control how many “echoes” you can hear against the original sound. It’s a good idea to keep the feedback amount very low, and even more so when there are longer delay times. This is because if many echoes are lasting a long time, they will begin to layer on top of each other, eventually obscuring the music. To simplify, you can think of feedback and delay time having an inverse relationship. That being said, there are creative ways of using infinite echoes, as this is not something that happens in nature and can create a psychedelic touch to your music.
The next important parameter is the level, or mix parameter. The delay signal is usually set at a lower level than the original signal, to imitate the energy loss of sound reflecting off of a wall. You can also create greater separation between the two sounds by applying a bass cut or treble cut on the delay signals. This is a useful trick if you’re having trouble achieving clarity of sound when using heavy amounts of delay.
Once you get a handle on the more common uses of this effect, you can experiment with some tricks. One well known trick is to set a delay pedal to the value of a dotted eighth note in whatever piece of music you’re playing, but play a constant eighth note line. This is a trick that is used by The Edge from U2.
Analog vs. Digital
Digital delays are characterized by a clean and pristine delay of the original audio. Analog delays have more “character” to them, because analog equipment naturally introduces noise to the audio signal. What is interesting is when the delay feedback increases and the signal is fed repeatedly through an analog delay, the quality of each delay degrades progressively. This is a characteristic sound of the “dub” style of music that is popular in Jamaica.
I hope you got some useful ideas from this! Until next time.