Knowing the basics of time based effects can help you greatly in applying them in the mix. Delay or echo takes the input audio signal and then, after some time, plays it back with the option of the level of adjustment.
There are four types of reverbs room, hall, plate, and spring, but all with the same principle of operation as making the sound to be reflected from different surfaces with a certain amount of delay.
Chorus and flanger are slightly different, and a chorus can give you a smooth or spiky sound while the flanger influences the speed. Harmonizer combines two signals, one with a changed pitch by consonant interval and the original signal.
Let’s dig a little deeper to understand.
Time Based Effects Explained
Although artistic endeavors are not usually organized and at times could be very chaotic, to say the least. Do not get us wrong, the creative chaos is not necessarily a bad thing, but it could be a very good idea to tame it at least just a little bit. To put it in other words, if you are a painter in a moment of inspiration and you do not know where is a particular brush that you need at the moment, chances are no painting would be made.
Exactly for that reason, all of the audio production knowledge is thoroughly categorized. It doesn’t really matter if you are a bedroom producer who mixes and masters his own tracks or an audio mixing engineer in a professional recording studio. You still need to know where your tools are and precisely what each and every one of them does. So before you can enjoy time based effects, let’s figure out what all such audio effects are and how we classify them.
Generally speaking, we can put all of the audio processing effects into three basic categories: dynamic, spectral, and time based effects.
As the name suggests, dynamic audio effects manage the dynamics of the audio signal and include effects such as compressors, limiters, and LFOs.
Spectral FXs are used to handle the frequency spectrum of the audio signal and include equalizers and filters. Technically, the distortion or any enhancer at that matter is a spectral effect since that we are adding harmonics to the frequency spectrum.
Time based effects are all the effects in which one or the other sort of time manipulation occurs. Those effects include delay, reverbs, chorus, flangers, and harmonizers.
Before we dive into the concept of delay, let’s get one thing clear, echo is a naturally occurring reflection of the soundwave, which gets to the listener with a noticeable delay regarding the initial soundwave. So, it doesn’t matter if your particular plugin says “echo” or “delay”, technically it still just a delay. So, what is the delay?
Delay is an audio signal processing unit that takes an input audio signal and then plays it back after a certain period of time. The application and the general usage of the delay effects very much depend on the artistic choices of the producer and nowadays are limited by only that.
First analog delays were made with modified reel-to-reel tape machines. The tape was placed in the loop, and read and write heads were adjusted, so the recorded sound was reproduced after the initial sound was played in repetition. One of the earliest composers who implemented this technique was Carl Heinz Stockhausen, who had some truly complicated delay systems.
Nowadays, a lot of modern digital audio plugins emulate tape-based delays with different levels of details. Basically, every digital delay has a very intuitive and simple set of controls. You obviously have dry/wet controls that let you blend the original signal and delayed one at the amount you comfortable with. Some delays offer you to control the amount of coloration in terms of tape-based emulation that would be tape-hiss.
And the most important set of controls would be, of course, the delay time. Here the audio plugin developers may offer you two options, based on the idea of synchronizing your delay to the project tempo. If your delay is not synced to the tempo, you may have controls in milliseconds, but if you are synced, you will control your delay time by the musical note lengths measurement that is used in sheet music.
Reverberation is also a naturally occurring acoustic process very similar to the echo. Since we know that sound is a vibration of the air, it is very sensible to assume that it can reflect from the surfaces denser than the air. So, every time when the soundwave moves from the source and interacts with the obstacle, it reflects back and reaches the listener with the delay. In nature, reverberation sometimes persists even after the initial sound stops and the reflected sound is lower in amplitude over time.
All of the analog and digital reverb units were designed to recreate the naturally occurring reflections of the sound. Some even consider the reverb to be the most important effect of them all. For some reason, as listeners, we do not appreciate dry sound with no reflections when it comes to music production. It may also be because rich and deep reverbs could make it easier to dive into the track’s atmosphere. Or because in nature, it is very hard to stumble upon the sound that has no reflections.
Four of the most commonly used and appreciated reverb types would be room, hall, plate, and spring reverbs.
Room reverbs tend to, in one way or another, emulate the sound of the room with noticeable pre-delay and short decay.
As you might have figured it out already, Hall reverbs are made to make a sound perceived as it is inside a big space of some sort, whether it would be an actual hall, church, or cathedral.
Plate reverbs do not actually emulate any space but rather a cleverly made device. This device consists of a small chamber with a metal plate inside of it. An input circuit makes the metal plate vibrate, and the output device registers the vibration. The most famous device of this sort is the one that was used in Abbey Road Studios in the 50’s and 60’s.
Spring reverbs function in a very similar way as plate reverbs, but instead of the metal plate, the metal springs were used. You can come across spring reverbs in a lot of vintage and also some modern guitar amplifiers.
In terms of a principle of operation, there are two types of digital reverbs. Algorithmic reverb uses mathematical equations to emulate the reflection of the signal. The convolution reverb uses a certain space’s actual reflections and projects it to the sound source, making it sound like it was recorded in this certain space. The reflection comes in the form of the impulse response, and such reverbs usually takes quite a lot of CPU power.
Chorus and Flanger
The essence of the chorus effect is the combination of two or more sounds with added delay and a bit distinct pitch. The distinctions are rather small, which makes it easier to perceive sounds as one without any inconveniences. Chorus can give you a rich and smooth sound or spiky and slightly aggressive pulsation. Some of the instruments can produce chorus naturally, while others need the plugins which create this effect.
The flanger’s basics are that one of the two signals that correspond with each other is a bit delayed. Sometimes the phase of the delayed signal can be flipped, and as a result, it will be another alteration of the same effect. The essence of the true analog flanging is the phased variation of the speed delays. As the technologies currently develop quite fast, digital flanger plugins can unite suitability and analog vibes well.
A harmonizer is a form of a pitch shifter that combines the signal with the changed pitch and the original signal. Usually, in changing the pitch, consonant intervals are used, such as perfect fourth and fifth, and that is why this device is called a harmonizer. You may think that since the pitch is changing, this effect should be classified as spatial, but the change in pitch is accomplished by changing the signal’s time constant. And they are reverting it back to the original to match the timing of the initial sound. So this is why we consider the harmonizer to be a rather time based effect than spatial.