The Basics of Audio Effects
What are the main effect categories and how do they work?
When adding effects to your audio tracks or to your song as a whole, you choose them largely from a group of three distinct categories. Each of these categories uniquely edits the sound in different ways to produce a number of quite different effects.
First we have the Filter Effects, which are related to the timbre of the audio, the tone color and quality that distinguishes it from other sounds of the same pitch and loudness. They are designed to amplify, pass or attenuate certain frequency ranges. These effects consist of Parametric and Graphic EQs (Used to alter or control the many different frequency response characteristics of an audio signal); High and Low Pass Filters (which pass through frequencies below/above their cutoff frequencies, and progressively attenuate frequencies above/below the cutoff frequency); Band Pass Filters (Both the High and Low pass filters in one) and others.
Next we have Delay Effects, which are effects related to the propagation of sound — The process of sound traveling through different mediums, which changes certain qualities. These effects include Reverbs (Created when the sound reflects off surfaces in different spaces, a little different to an echo); Phasers (Used to filter a signal by creating a series of peaks and troughs in the frequency spectrum, creating a sweeping effect); Flangers (The mixing of two identical signals together, one of which is delayed by a small and gradually changing period); Choruses (Individual sounds with very nearly the same timbre and pitch converge and are perceived as one.); and others.
Lastly we have the Dynamic effects, Which are related to Amplitude over time. The dynamic range of sound is the ratio between the largest and smallest values of amplitude, therefore the dynamic effects alter this aspect of audio. It consists of effects such as Compressors (Can either reduce loud sounds while leaving quiet sounds unaffected, of the exact opposite — Both serve to reduce the overall dynamic range); Limiters (A limiter is a very strong form of compression, generally using a ratio of 10:1, which is the ratio that it lowers the amplitude by after it passes a certain level. There are also brick wall limiters use ratios of 20:1 and over); Expanders (Works in the opposite way of the compressor, making quiet sounds more quiet and/or loud sounds more loud, therefore increasing the dynamic range); and Gates (Gates limit sounds of a certain level, only those above this limit can be heard, while a sound outside this threshold is removed).
I hope this has helped you to understand the three basic categories of audio effects and how they relate to the altering of an audio signal, there is much more that you can learn about them but that’s for another post…
