When using delay, it is useful to know how to time your delay with your BPM, how to make the delay taps sound like one source, and how to introduce stereo imaging with delay. Additionally, it’s best to know some common delay functions like crosstalk, feedback, and modulation.
Reverb and delay seem like very different forms of processing, but they work in very similar ways - algorithmic reverb is made up of multiple delay taps to emulate the sound of room reflections. Delay plugins typically utilize fewer delay taps, making each delay a little more obvious.
Reverb can be used somewhat similarly to delay and vice versa, but they do have distinct sounds. Let’s quickly listen to both with similar settings to hear how the additional delay taps of the reverb alter the character of the effect.
The first delay effects were created using either multiple tape machines or a tape machine with multiple tape heads - for example, if you had a tape machine with 2 tape heads, and ran 2-track tape through it with both heads on, you’d get a delay.
The delay would be caused by the distance between the tape heads, as the 1st head would read the signal, followed by the second head reading it moments later, creating 2 identical signals in quick succession.
Today we can emulate this effect with plugins, so let’s take a quick listen to that.
If a delay is less than 130ms we perceive the 2 signals as being 1 signal - this is a great option for thickening vocals, guitars, or any source you want to sound fuller, since it’ll just seem like a louder more complex signal instrument.
If the delayed signal is longer than 130ms, we hear the delay and original signal as 2 separate signals. So in short, if you want a thickening effect, keep the delay time under 130ms.
Most delay plugins let you quickly sync the delay taps with your host BPM - you’ll typically notice 1/4 note, 1/2 note options, and so on. But we’ll get more control if we set the delay time manually, by dividing 60000 by the BPM to get a quarter note.
Once we have this number we can make the delay a little shorter to create a pushed delay, or a little slower to create a dragged delay. Let’s listen to these slightly imperfect delay times and see how they affect the signal.
When using a stereo delay plugin, it’s important to know how it might affect your stereo image - if you set the delay times of your left and right channels to different times you’ll greatly affect your stereo width. Sometimes this is done purposefully, like with a doubler plugin.
But it can have a negative effect as well. That said if you’re delaying your left and right channels, keep them set to identical times unless you’re purposefully expanding your stereo image.
Let’s look at 2 important delay functions - feedback is the amount of the delayed signal that will be fed back into the signal chain. Since this value is less than the original, it won’t create increasingly powerful feedback like in an unintentional feedback loop but will diminish over time.
Crosstalk is the amount of the left channel being fed into the right and vice versa. This can have a widening effect due to mild phase cancellation. Additionally, this function emulates analog gear, since mild crosstalk was a defect of a lot of analog equipment.
Modulation is an important part of many delay plugins - most modulation is either time-based or frequency-based, but on occasion amplitude-based modulation is included. Frequency-based modulation is usually called vibrato, amplitude-based is called tremolo, and time-based doesn’t seem to have a separate name.
By introducing modulation to a delay plugin, we shift the time of the delays, the frequency of the delays, or the amplitude of the delays. This will of course depend on what type of modulation the plugin you’re using offers.
Delay can be used for creative and writing purposes - for example, we can use delay on a snare to change the performance. If the delay tap is strong enough, it’ll just sound like an additional snare hit, the same being said for any other instrument.
With that in mind, experiment with delay to see if you can create unique compositions, utilizing multiple delays as a unique form of time-based arpeggiation. With frequency modulation included, you could even make it sound like an actual arpeggiator.
The point is, there are a lot of applications for delay extrinsic of how it’s typically used.