I'm going to start this column off by admitting that the delay effect is my favorite effect for guitar, or any other instrument for that matter. If I'm stranded on a desert island, and I am allowed just one effects processor for the rest of my days on Mother Earth, let it be a decent digital delay with about 10 seconds of delay time. Delay devices are true effects; they were not invented to correct sounds (like equalization), nor were they created to keep tape from distorting (like limiters). They were not even designed to replace natural ambiance (like reverberation). In my opinion, they exist to make our time in the studio an aural joy.
I think that sometimes the importance and versatility of the delay effect gets lost in the shuffle. These days you can buy multi-effects processors that can do between eight and twelve effects at the same time, including delay, reverb, pitch shift, flanging, distortion, gating, chorus, compression, etc. As we'll see, a number of effects included in a multi-effects device are really only variations on the delay theme. You can do an awful lot with just a dedicated digital delay processor. Understanding the basics of the delay effect will help you to apply delay in many more ways than you might have thought. I'll be covering several common delay applications that you can try immediately, and hopefully give you ideas for creative new uses for your delay processor(s).
In this column, I'll be focusing on digital delay processors, which are relatively inexpensive, and offer much higher quality than the old analog delays (or even the older tape delay units). Actually, guitar stomp boxes were probably the one of the last analog delay units you could easily find. Today, however, most foot pedals are only available in the digital form.
All digital delay devices repeat an incoming signal at regular intervals. They are sometimes called echo devices, since they remind us of the natural result of shouting in a cave or yodeling down a canyon. Delays also have knobs or other controls over parameters such as delay time, delay level (mix), modulation level, modulation speed, and feedback level. However, not all delays have controls over every parameter, and they also vary in the level of control you are allowed. For example, one device may allow delay times up to 10 seconds, another device may only be capable of 2 seconds of delay.
Delay time is the time interval between the original input signal and the delayed output signal and is measured in milliseconds (abbreviated 'ms'). As you will see, different delay times result in some radically different sounds.
Delay level, or mix, is the ratio between the amount of original input signal (the dry signal) and the amount of delayed effect (the wet signal) that you will hear at the output. You set this control based upon how the delay is hooked up in the signal chain. If the delay is used on a mixer's auxiliary send and return, you would set the mix to 100% wet, so only the effect is present at the output. This is because the original signal is still present at the mixer's channel output, and you normally have a fader or knob to control the level of effect returning from the delay device. If the delay is used in-line between say, a guitar and an amplifier, the mix is usually set between 20% and 80% wet, depending on how loud you like to hear the delays or echoes. 80% wet could potentially overwhelm the original sound, whereas 20% wet might be a very quiet or subtle delay effect.
Modulation level and modulation speed are controls that can automatically vary the pitch of the delayed signal (for chorus effects), vary the overall delay time (for flanging effects), or vary the center frequency of the modulation (for phasing effects).
Feedback level controls the amount of output signal that is returned to the input. This allows you to control the number of repeats that are heard, from a low of one repeat (when feedback level is at it's minimum setting) to a seemingly endless series of repeats, achieved by setting feedback level to it's maximum value.
Two main characteristics of the digital delay determine the overall sound quality of the device: the sampling rate (sampling frequency) and the quantization level. The sampling rate is the number of sound samples (or pieces) per second into which the input signal is digitized. The higher the number of samples per second, the higher the sound quality. Sample rates can vary from 24kHz (24,000 samples per second) to over 48kHz (48,000 samples per second). A compact disc is sampled at 44.1kHz. Some recording engineers would argue that anything over about 12kHz is overkill in a delay device, since echoes don't naturally occur as perfect, full frequency duplications of an original sound. This may be true, however, you can always run the output of a delay into an equalizer and roll off some of the higher frequencies for a more natural sound. The dynamic range of the digital delay is a little less than one-half the sampling rate, so that a device with a 44.1kHz sampling rate has about a 20kHz bandwidth.
The quantization level determines the dynamic range of the delay and is specified in bits. The higher the number of bits, the greater the dynamic range, and the better the sound quality. It's rare these days to find delay processors that do not use at least 16 bits, compared to 8 or 12 bits in the 'olde' days (before 1991). Now, 20 or 24 bit processors are starting to appear at your local music store. Each bit yields roughly 6dB of dynamic range, so that a 16-bit delay device has a dynamic range of about 96dB.
Let's take a look at some typical uses, as well as some of my favorite applications of digital delay and why I like them.
What It Is and How To Get It: Loop music is practically it's own a musical subculture in which delays are long enough to equal a beat, a musical bar or a section of music. Typically the delays are over 400 ms. Take a mono track and set the delay time to match the length of say, a half note. Use a single delay at first. To compute the proper delay time in milliseconds, take 60,000 and divide it by the tempo (in beats per minute, or bpm). That will give you a delay time to match a quarter note. For a half-note delay, multiply the delay by 2, for a whole note delay, multiply the delay by 4, etc. For example, a half note delay at 90 bpm is 60,000 / 90 = 666 ms x 2 = 1332ms, or a little over 1 second. Matching repeats to tempos is a good technique to learn for just about any delay application (and it's very easy if you use Guitar Nine's Delay Time Calculator).
Why I Like It: I find using delay for loop music to be a great improvisational tool. The half-note or whole-note (one bar) delays are long enough so that if you listen to the delays as you play you can harmonize yourself in a very musical, yet constantly changing way. When you get comfortable with a single delay, set the feedback level to get 2 or 3 delays. This will cause the harmonies to be much more complex, and results in a denser barrage of notes. You'll sound like a one-man guitar ensemble.
What It Is and How To Get It: Fake stereo is simply taking a mono signal and turning it into a pseudo-stereo image. Take a mono track send it to a delay processor, pan the original track hard left and the delayed track hard right. Use anywhere from 10 to 40 ms of delay time, with feedback set to a single repeat.
Why I Like It: Are you lazy (at times)? Instead of double-tracking that rhythm guitar part, set up the fake stereo, and prepare to be blown away by a great sounding rhythm guitar sound. For additional variation, try equalizing either the original track or the delayed track. Or, to induce motion sickness, turn both pan controls rapidly from side to side during mix down.
What It Is and How To Get It: Slap echo, or slapback echo is a ricochet effect that tends to "fatten" a guitar sound quite nicely. Take a mono guitar sound send it to a delay processor, pan the original track somewhere close to the center of the sound field and the delayed track hard right. Use about a 75 to 150 ms of delay time, with feedback set to a single repeat.
Why I Like It: Slapback echo is great because it sounds natural in a wide range of musical styles, with just about any guitar sound (clean, distorted, etc.) It even makes any beginning guitar player sound like he has been practicing more than he has.
What It Is and How To Get It: Delayed reverb is simply feeding a slapback echo into a reverb unit to delay the start of the reverb. Set up your delay like the slapback example above. Then, take the 'wet' output of the delay and feed it to a stereo reverb unit. You can start with a medium or large hall or room setting on the reverb.
Why I Like It: I like this rather spooky effect a lot, especially if I keep the number of delays down to 1 or 2. It adds a stimulating, sensual sound to a slow guitar solo or a saxophone lead. It also has an even more profound effect if you use an even slower delay time (try 400 to 500 ms.), and use it for only for sections of a solo where you want to really draw the listener in.
What It Is and How To Get It: Chorus (sometimes called doubling), is the use of a very short delay, coupled with modulation of the pitch of the delayed signal, to achieve a full, thick sound. Take a mono track send it to a delay processor, and use anywhere from 10 to 20 ms of delay time. Turn the modulation level up bit by bit until the desired amount of richness and thickness is achieved. Some stereo delay processors allow you to control the amount of modulation of the pitch separately for the left and right outputs. If you can set them slightly differently, the overall effect will much more like an ensemble of guitarists, attempting to play in unison.
Why I Like It: I rather prefer the sound of chorus on clean, arpeggiated guitar passages, rather than on distorted guitar solos. Using chorus on overdriven tracks seems to me to be trying to sweeten something that took some care to grunge up in the first place. Some clean guitar tracks sound much too thin, and the chorus effect really helps give the guitar more sonic thickness.
I've just scratched the surface with a few ideas that will help you get started with delay effects. Most really creative uses of delay start with the idea that you don't just simply hook up a delay to the auxiliary sends and receives of a mixing board and twiddle the delay time knob. Keep in mind, the output of the delay unit can go to anywhere you want: an overdrive, an exciter, it's own mixer channel, or another delay. Routing the 'wet' signal through other devices will give the delay it's own character and add a whole new dimension to the effect.
Delay is an addictive effect, so you may have to restrain yourself when you get a little too carried away. Have fun and get creative with your digital delay and send me your new delay applications. Don't delay, start using
Dan McAvinchey is a guitarist and composer living in Raleigh, NC.
He believes every musician or composer has the power to write, record and release their own music.
His 1997 CD release on Guitar Nine was entitled "Guitar Haus".
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