Right up there with compression and EQ, delay-based effects are arguably the most ubiquitous tools in a producer’s arsenal.
Most musicians associate the word “delay” with repeating echo effects, but echo is just one of the many applications for delay.
In this tutorial, we’ll reminisce a bit about the history of these tools, then take a closer look at the underlying technology and its applications for producers.
History of the delay
The first use of delay was pioneered by the French artists who led the Musique Concrète movement way back in the early 1950s.
This high-concept – and utterly revolutionary – musical movement made extensive use of tape loops to repeat audio recordings, creating rhythms and drones out of seemingly ordinary sources like water droplets and nature sounds.
Many historians agree that Musique Concrete was the first true electronic music, using tape in much the same way that we now use samplers – but over half a century ago!
Later in the 50s, ambitious inventors like Ray Butts and Mike Battle turned the tape loop concept into usable products like the Echosonic and Echoplex (pictured at right).
These first delays were composed of a small tape recorder that played a continuous loop of tape.
By varying the position of the record and playback heads, as well as changing the tape speed and varying a few other parameters, intrepid producers could adjust the delay time, number of repeats and other signal characteristics.
These early tape-based delays have such a unique character that they are still highly sought after on eBay, often fetching hundreds – even thousands – of dollars.
In the late 1970s, simple analog circuits called “bucket brigade devices” simulated tape delay with equally unique results, but this was quickly superceded by digital circuitry, resulting in the delay as we know it today.
How a digital delay works
While tape and analog delays have their own unique character and depth, digital delay technology ratchets up the entire concept by an order of magnitude, especially when you factor in the massive amounts of memory available in current computer technology.
Here’s how it works.
A digital delay functions as a simple audio recorder by capturing an audio signal, holding it in memory for a specified time, then playing it back, thus creating a single “echo. “
One of the keys to the echo process lies in blending the delayed signal with the original, unaffected audio.
The signals are known respectively as wet (delayed) and dry (unprocessed).
Without the presence of the dry signal, there would be no echo – just the original sound played back a little later.
To make the echoes repeat multiple times, a parameter known as “feedback” is implemented.
Feedback sends a bit of the delayed signal back into the input of the delay, causing it to continually repeat at progressively quieter volumes until the echo fades to silence.
Adventurous producers sometimes set the feedback level at extremely high amounts, creating a wash of echoes that fade out over a much longer period of time.
This technique is often used during breakdowns, adding tension and drama to a track’s overall story.
Types of delay effects
Since delay times can range from fractions of milliseconds to several minutes, there’s an extraordinary range of results available.
Here are some of the more common effects that can be created by simply varying a few parameters.
Resonators. Sometimes referred to as a “static flange,” you can create metallic, ringing pitches by setting the delay time to very short lengths and increasing the feedback to near maximum, thus causing the delayed signal to repeat so quickly that it generates a pitched tone.
If you’re mathematically inclined, you can calculate the specific pitches that the delay produces in this manner, here’s how.
When a delay is set to one millisecond (one thousandth of a second) with a very high feedback amount, the delayed signal repeats one thousand times per second.
Since frequency is measured in Hertz – a measurement that correlates to one cycle per second – a delay that’s repeating one thousand times per second will have a frequency of 1000 Hz, also known as 1 kilohertz (kHz).
To drop that pitch by an octave, just do a bit more math and double the delay time to two milliseconds.
Since two divided by one thousand equals five hundred, a two-millisecond delay will result in a pitch at 500 Hz.
For those who aren’t as mathematically inclined, just fire up Ableton Live’s Resonators device (pictured above).
The Resonators device applies these same principles, but mercifully, it allows users to dial in multiple pitches using standard musical terminology, making the entire process a relatively painless affair.
Flange/Chorus. It may come as a surprise to some, but these classic modulation effects are created by simply using an LFO to modulate the delay time as the signal passes through the effect.
The main difference between a flanger and a chorus is that flangers use high feedback and extremely short delay times, usually under ten milliseconds but sometimes as much as twenty milliseconds.
Chorusing and flanging share overlapping delay times, so there is no clear point at which one becomes the other – it’s more of a morphing thing.
That said, chorus times can range as high as forty milliseconds, after which the effect veers into a territory that is sometimes referred to as “doubling” by some producers.
In a future tutorial, we’ll go into much greater depth on the applications of various modulation effects like chorus, flanging, phasers, and such.
Slapback. Fans of old school reggae and dub genres will be familiar with an effect called “slapback,” which is essentially a very short echo with a lot of feedback and a touch of filtering.
To recreate this effect, try tinkering with delay times in the 90 millisecond range and vary the feedback amount.
If your delay plug-in supports it, spend a bit of time fiddling with its EQ or filter, as this will allow a wider range of textures.
As you increase the delay time, the slapback effect will become more distinct until it transforms into the echo effect we all know and love.
Other delay variations
Most of the above effects can be created with pretty much any off-the-shelf delay, but there are also more advanced tools that allow for further audio customization.
Ping-pong. Ping-pong echoes consist of a pair of delays, each panned to opposite sides of the stereo field, which allows for the creation of effects that bounce around the stereo field rhythmically.
Ableton Live’s ping-pong delay implementation also offers control over the frequency spectrum of the echo via a simple EQ/filter tool.
Multitap. Multitap delays up the ante further by giving the user access to even more individual delay lines, each with its own panning, feedback and often, filtering characteristics.
Pictured at the top of this article is Logic’s Delay Designer, which is currently the most sophisticated delay to ship standard with any DAW software.
Some multitap delays include complex routing options that allow each of the individual delays to feed into and thus interact with the others.
A multitap delay gets really deep, really fast, so it’s wise to master the basics before taking the plunge – unless you’re fine with sticking with presets until you get up to speed.
Reverb. The ambient effects created by reverb are produced by extremely specialized and complex delay algorithms, optimized to simulate the acoustic characteristics of various rooms and spaces.
Since the reverb process is a world unto itself, we’ll be devoting an entire tutorial to its subtleties in the not-too-distant future.
Until then, we’ll leave you with one extremely important tip to contemplate.
Since repeating delays actually add additional audio signals to your mix, it’s all too easy to turn your track into a mushy mess by using too much or too many on a number of tracks.
Instead, we recommend limiting the use of echo effects to only one or two specific instruments that you want to highlight and enhance.
This way, you make the most of what a delay has to offer without overwhelming the other parts of your track.
Until next time…