The Concept Behind Dynamic Processors: Threshold, Ratio, Attack and Release

Introduction To Music Production, Week 4

Hi, I am Luis Carlos Pinedo from Toluca, Mexico. This lesson is for week 4 of Introduction To Music Production at

Coursera.org. I will be teaching the concept behind dynamic processors and describe the concepts of threshold, ratio,

attack and release.

So, lets start

When we begin to manipulate the dynamic range in the post-production process of recording, well have to complete

two tasks: compression, which is reducing the dynamic range, and expansion, which is increasing the dynamic range.

There are two ways to accomplish the reduction of dynamic range; the first is to make the loud stuff quieter and the

other is to make the quiet stuff louder. With these we get a much better performance.

And there are two ways to increase the dynamic range; we can either make the loud stuff louder or make the quiet

stuff quieter. The way, the distance between the quiet and the loud will be increased.

The most common thing to do is reduce, or compress the dynamic range. For doing this in a recording, we could chop

up the recording and isolate each individual section with editing, and increase the gain with a clip gain feature in the

DAW.

Another common way to adjust the level of the recording is whats called riding the fader, in which we play back

the performance and move the fader up and down, kind of opposite the dynamics of the performance.

So if the part of the recording gets louder, we bring it down, or if gets quieter, we bring it up. That is what a dynamic

processor does, it follows instructions.

So dynamic processors just change volume, and they do it listening, analyzing the signal itself and responding to it.

These are all what we can non-linear devices, and can be compressors, limiters, expanders and gates; they are all

divided into two segments, the side chain section, which analyzes the input signal, and the other is the volume fader.

The side chain section, also known as the key chain, analyzes the signal and calculates the envelope of the audio.

The envelope is a signal that represents the average level at any point in time. Once we have this we can use to

control the volume fader.

They all have a set of different parameters, and these are the more important:

-Threshold: Is the level at which the dynamic processor starts to function. We have to adjust it based on the input

signal.

-Ratio: Is the amount of compression, once the signal crosses the threshold. For example, if we have a ratio of 2:1, it

means that for every two decibels in the input, well have one decibel in the output.

-Attack: How fast the fader moves or the volume will change at the beginning of the sound, when it crosses the

threshold.

-Release: How fast the fader moves or the volume changes when the signal crosses back to the threshold.

So in conclusion we learned that dynamic processors are rule-based gain controls, in which the major parameters are

the same, but the rules are different. They have a set of parameters: threshold, ratio, attack and release and we

learned them individually.

So I hope you enjoyed this presentation and reinforced your knowledge about this weeks class.