Basic types of audio effects plugins

(I'm writing this article as part of the Introduction to Music Production course on Coursera.)

In a digital audio workstation (like Logic, Reason, Pro Tools, etc.), there are many different audio effects that can be applied to tracks. These effects can change sound in almost any way, and there are countless plugins to choose from! Today, we're going to take a look at three of the main categories: dynamic, delay, and filter effects.

Dynamic plugins affect the amplitude of a sound. Basically, they function like automatic volume control. This includes compressors, limiters, expanders, and gates, among others. This is what the "Compressor" plugin in Logic looks like:

Compressors are used to reduce the volume of the loudest parts of a track.

Delay effects have to do with the propagation of sound. They play slightly modified sounds back at a slight delay, which can have a variety of effects, like simulating the sound in different physical spaces. Delay effects include plugins like reverbs, delays, phasers, flangers, and choruses. This is "Space Designer," one of the reverb plugins in Logic:

Recording signal flow

(I'm writing this article as part of the Introduction to Music Production course on Coursera.)

Let me give you a rough overview of what happens every time I hit my snare in my studio.

My brain generates a signal. It starts in the motor cortex, racing across each neuron as an action potential, and crossing each synapse by the release of specific neurotransmitters. It travels through the thalamus, then down my spinal cord. It goes to nerves in my arm, contracting muscles, which in turn flex and extend my joints. Starting from my shoulder, a whiplike motion occurs. It moves through my arm, elbow, wrist and then fingers, exerting force on the drumstick in my hand. The drumstick accelerates downward, making contact with the batter head of my snare:

When the drumhead begins oscillating, it alternates between compressing and rarefying the atmosphere, creating longitudinal waves of sound pressure variation. These sound waves travel through the air and make contact with the diaphragm of this Audio Technica M4000S dynamic microphone: