Concept behind dynamic processors


Hello Moocsters!

I am David Sabalete from Barcelona in Spain. This lesson is for week 4 of Introduction To Music Production at Coursera.org. I will be writing about the "Concepts behind dynamic processors". I apologize for my level of English, which is not my mother tongue.

There are two task we can to apply to our sound in order to manipulate its dynamic range:
  • Compression
  • Expanssion
Compression means to reduce the dynamic range and Expanssion means to increase it.

However it is more common to apply only one of them.

When we want to reduce the dynamic range, we can make the loud part of the sound quiter or make the quiet part louder.
We will get a more consistent performance or more consistent recording when we apply these changes to the sound.
When we want to increase the dynamic range, we can make the loud part louder or make the quiet part quiter. Both operation increase the difference between the loud part and the quiet part.

If we have a sound with different levels, we should try to make each different part closer in level. It is possible to achive that in different ways.
  1. One way could be to separate or isolate each individual section with editing. Then, increase the gain using some feature of the DAW.
  2. Another really common way is called "riding the fader". Here, we play back the sound and we move up and down the fader the opposite of the dynamics of the sound. What we are doing is drawing a line along the bottom side of the wave form in the DAW.
That means when the sound gets loud, it brings the level down and when the sound gets quiet, it brings the level up.
It is a simple procedure that a computer can do. In fact, that is what a compressor does. It apply a rule. If a sound gets over a specific set point or threshold, start reducing the level. And if the sound gets below that threshold, it brings the level up.

Dynamic processors just change volume in an intelligent way. They do it by listening, by analyzing the signal itself and then responding to it. Dynamic processors are called non-linear devices. They react differently at different amplitudes.

Parameters of Dynamic Processors


Compressors, limiters, expanders, and gates are also non-linear devices.  All of them have a set of parameters: threshold, attack, release and ratio. But the rule they use is different.

And talking about Compressors, these are their parameters and their effect.
  • Threshold: The level above which compression is applied to the audio.
  • Attack: How soon the compressor starts to compress the dynamics after the threshold is exceeded. If volume changes are slow, you can push this to a high value. Short attack times will result in a fast response to sudden, loud sounds, but will make the changes in volume much more obvious to listeners.

  • Release: When the compressor is increasing gain to the level determined by the ratio, or, to zero dB, once the level has fallen below the threshold

  • Ratio: The amount of compression applied to the audio once it passes the threshold level. The higher the Ratio the more the loud parts of the audio will be compressed. The Ratio sets the slope of the blue line on the graph above the threshold.

And that's all about this short introduction to Dynamics Processors. I Hope it helps someone. Thank you for read it.

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