Using Delay Effectively
Date 2004/4/1 0:56:00 | Topic: Effects
| Using Effects Effectively Part 2
Delay
By: Gary Allen
In this edition of “Using Effects Effectively” we are going to talk about one of my personal favorite effects. This effect is called delay. Like reverb, delay is an echo style effect. However there are some very distinct differences between delay and reverb. In the article we will cover what delay is, some history on types of delay, and some tips on using delay. I hope you enjoy this article.
What Is Delay?
If you read “Part 1” of this series you will remember that reverb is a combination of reflections and absorption of sound waves. Each time the sound is reflected a part of it is absorbed into the natural environment causing the sound to diminish with each reflection. This process of reflection and absorption continues until the sound diminishes below the threshold of our hearing capabilities. Delay is similar to reverb, but the properties by which it is controlled are different resulting in a completely different effect.
Instead of an increasing number of decaying reflections, delay is just a few very distinct repetitions. These repetitions will be the same or very close to the same volume of the original signal. On most delay units you can change the timing of these repetitions from milliseconds to several seconds. The primary job of the delay effect unit is to store a copy of the original signal and then play it back at predetermined intervals. Delay has a couple of uses in music today, but the one we are going to look at here is the use of delay for sound enhancement. Over the years there have been many technologies incorporated into creating new ways to process delay. Let’s take a look at the history of delay.
Line Delay
The very first delay ever used was for enhancing the quality of radio broadcasts. What the radio station would do is send their signal out over a phone line from one end of the country to the other and then back again. When it returned it would be mixed with the original signal and then broadcasted. The amount of time it took the signal to leave and come back over the phone line would be the length of delay. (Can you imagine what their long distance bill must have cost? This form of delay was not very flexible and for obvious reasons it is not used anymore. There are just too many more flexible and cost effective alternatives on the market today.
Tape Delay (Tape Slap)
With the invention of tape recording came new possibilities in delay technology. With the ability to record a sound and play it back came the tape delay. Tape delay units were usually large yet portable tape recorders that incorporated a recording head and a playback head. (A recording head records a sound onto a tape and a playback head plays the recorded sound from the tape.) While the guitar player is playing the original signal is recorded by the recording head and then it passes through the playback head milliseconds later causing the delay effect. The length of delay depended on how far away the playback head was from the recording head. Now delay could be used in live sound applications. As these units developed over time they started adding more playback heads and tape speed controls giving delay more flexibility than it had ever seen before.
With the addition of more tape playback heads delay could now feature more repetitions of the same signal instead of just one. The addition of speed control allowed for the first time the flexibility to change the delay speed at will. Some of these units are still used today in recording studios and in live applications although it is rare.
Analog Delay
The next step in making a portable user friendly delay unit was the analog delay. The signal would be split in two upon entering the analog delay unit. Half of the signal would be directed straight through to the output phase while the other half would be redirected. This redirected signal would pass through a series of capacitors that would slow it down and then it would meet the other half at the output. Because the signal had been slowed down as it went through the series of capacitors it would reach the output phase just a little behind the point that the two signals had been split, thus causing the delay effect. These units had adjustable delay times, but were notorious for losing high frequencies during long delay times. These units are still used today although not nearly as much as the more popular digital units that have flooded the marketplace. I have known players who still believe that the analog delay is the only way to go. Some players still covet these units.
Digital Delay
Digital delay is by far the most popular delay used today. Like many other effects units the digital domain has taken over the market. The invention of digital signal processing takes delay into a very flexible and affordable arena. Digital circuitry was a perfect fit for the process of storing a signal and then playing it back at a specified time interval. It also solved the problem of losing the high frequencies on longer delay times.
These units were being designed in the late 70’s but were so expensive that many studios and musicians continued using the analog delays, but as technology advanced the prices and quality of the digital units became more appealing. Some companies still make analog delays but for the most part everyone has jumped on the digital bandwagon.
Digital technology allows for greater flexibility and longer delay times in a smaller unit such as the stomp box. Digital delay is also used in many multi effect units.
However some musicians feel that digital processing has too much of a mechanical sound and does not truly replicate the feel of the older analog units. Despite this complaint digital delay is still the most used application of delay today by the professional and the novice alike.
What is the next step in delay technology? I am not sure myself, but in my research on effect and technology the one thing that seems to be hinted at is optical technology. Optical technology as I understand it is the use of light picked up by sensors. I do not understand this concept yet by the idea is intriguing. I will update this article when more information on the subject is available.
Delay as an Effect
Delay has a couple of uses that are for totally different things. The first one we are going to look at is delay used as a sound enhancement. Delay can be used on virtually any instrument and on vocals. A short delay time can create a lush full sound while a very long delay time can actually allow you to solo over yourself. It is an easy effect to learn to use and the flexibility of the effect is as big as you imagination can take it. On some units you can actually set the volume level of the echoes as well as the speed of the repetitions. Play around with the controls and be creative. You may just come up with something new.
Delay as a Sound Reinforcement Tool
The second use for delay is for sound reinforcement applications. This is not so much used as an effect as it is to help maintain quality sound in large venues. To understand why delay is used in this application you must first understand that electrical signal move at a much higher speed than sound. Keeping this in mind let me set you up with an example.
You just bought tickets to your favorite bands show but all you could get was seats way in the back. As you are watching the show you notice that the sound seems to be coming from the sides with an annoying echo coming from the front. In this scenario the sound from remote speaker toward the back of the stadium are reaching your ears before the sound of the main speakers toward the front. This is because the electrical signal is hitting all the speakers at relatively the same time, but you are hearing the sound from the remote speaker sooner than the mains because you are so much closer to them. It takes longer for the sound from the main speakers to reach you causing the unwanted echo. Here is where the use of delay comes in handy in a sound reinforcement application.
If the signal to the remote speakers is delayed longer than the signal to the main speakers it gives the mains sound waves time to reach your ears at about the same time the remote speakers sound does. This gets rid of the unwanted echo effect. In essence you can use a delay unit to stop an unwanted environmental delay. The amount of delay needed depends on the distance the remote speakers are from the mains.
The use of time delay in a sound reinforcement application can create the illusion that the sound is all actually coming from the main source. If you are watching a band play in front of you, it would feel kind of strange to hear the sound coming from the sides or from behind.
Well I hope you enjoyed reading about some of the history and applications of delay. Stay tuned for part 3 of Using Effects Effectively coming soon.
Gary Allen
gary@guitargearheads.com
Copyright © 2004 Allen & Halberg Publishing
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