Understanding Effects: Delay

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.

Delay Time

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.

Feedback

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.

Levels

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.

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Understanding Effects: Distortion

I notice a lot of guitar players tend to be, through no fault of their own, groping in the dark when it comes to using effects pedals. I find that a big problem is that manuals only delve into quick-and-easy type settings that doesn’t explain much about what is actually happening to the sound. I’m going to try and demystify some of this so that you can learn how to get the exact sound you are going for.

To begin the series, I’d like to talk about a fundamental guitar effect, that’s become so ubiquitous that it comes built in to most amplifiers: distortion.

We all know the sound – a screaming guitar solo or a thunderous riff are products of distortion that have become the hallmark of the rock guitar sound. So what is happening to the sound that causes this change? To put it simply, it does exactly what it’s named – it “distorts” the actual sound waves that are coming from you guitar. Imagine a sine wave with its nice flowing curves when it’s visualized. Distortion occurs when this signal is boosted past the limit of the maximum volume. The wave literally hits a ceiling, visually chopping off the top/bottom curve to produce a flat part in the wave. This is what we hear as distortion. Different types of distortion are available, but they are generally categorized as saturation/overdrive (mildly distorted) and distortion (greatly distorted sound). When these deformities in the sound waves happen, they also create harmonics/overtones that we perceive as adding a richness to the sound.

The controls that we have over this effect are generally: level/volume, and the amount of distortion (sometimes there’s a bit of EQ as well). It’s easy to hear the difference each of those controls make, but there are some traps that you will want to watch out for. Distortion is a dynamics based effect, meaning it affects our perception of volume. If you’re switching between a clean and distorted sound, it’s important that the volume level transitions smoothly. This is more difficult than it sounds, because if a distorted signal and a clean signal were to have the same amount of energy, the distorted sound will be perceived as being louder. Secondly, when you’re using heavily distorted guitars against the drums, there can be a lot of overlapping high frequencies between the cymbals (and crowd noise, if you’re in a venue) and guitar sound. You can avoid this by using and equalizer to get the guitar to sit in an less occupied part of the frequency spectrum. Many distortion stomp boxes will have a built in tone control to deal with this issue.

Overdrive is a type of distortion that is often associated with driving the power amp to distort. This is distinct from (heavy) distortion which is done in the pre-amp stage. Power amp distortion is generally described as a “crunch” tone. Historically, this is how all early forms of distortion were achieved, before amps came with the effect built-in. That means if you want a vintage blues/rock type of sound, you should go for this type of distortion by cranking that tube amp up.

Now for a few tips and tricks. When it comes to distortion, I want to emphasize that less is more. Even heavily distorted genres like metal can benefit from this mindset. Dynamic range is lost as more distortion is used and eventually you will end up with little difference between the loud and soft parts of your playing. If we were to take this idea (less is more) to the extreme, we get to the territory of saturation. This is a type of distortion that is most often associated with analogue gear that is powered by tubes. By using an almost imperceptible amount of distortion that retains most of the original sound, you’re able to add a subtle layer of overtones to the signal.

The Tone Knob

How many of you out there can explain EXACTLY what a tone knob does and how it’s affecting the sound of your guitar? Some of you may say that it is used to reduce the high frequencies of an electric guitar, but that’s really only half the story. It does explain the change in sound, but let’s take a closer look at what’s really going on.

The tone knob on most electric guitars operates as a low pass filter. A low pass filter operates like it is named. It is a filter for your sound that allows frequencies lower than the set limit of your signal to pass through; IE it filters out all of the frequencies above whatever frequency you choose to set as the threshold. The frequencies are often reduced at a rate of -12dB per octave and sometimes -24dB per octave.

Now that we understand what’s really going on, we can understand the most logical use for the tone knob: to set a high frequency limit to where a guitar sits in a mix. In a rock band type setting, this means avoiding mix conflicts with other high frequency instruments such as cymbals and vocal sibilance (the “ssss” sound). There is a balance to be struck here, however, as the guitar pick attack (which is the most important part of a guitarists’ tone) can get lost if you go too far. What I recommend is to slowly turn the tone knob down until you just start to hear it affects your pick attack, and then back off. Once you find the sweet spot, you generally won’t need to adjust it too much over the course of a performance.

There are other ways of using the tone knob. In the jazz guitar world there are players who have used the tone control to the extreme, most notably Jim Hall. He was known to roll the tone knob down all the way down in order to achieve a dark and warm tone that became his sonic signature. Note that this was a stylistic choice in the context of the right musical setting, however, and that a similar guitar tone would likely not work in a metal band. Speaking of rock bands, Eric Clapton, and his signature “woman tone” was a result of turning his tone knob all the way down while playing with distortion. The reason this works is because the distortion effect creates overtones that allow the guitar to still retain some high frequency information in the tone, thus allowing it to cut through a loud band easier than a clean tone would.