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Mastering Dynamic Range Compression

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Dynamic range compression will make your songs.....quieter.

You Think I'm Kidding...Right?

Defying Conventional Wisdom

Those of you familiar with basic audio wisdom tells you the exact opposite.

By that I mean...

You’ve probably heard if you want your tracks louder, you gotta apply compression.

The Honest Truth

What is audio compression?

Dynamic range compression automates volume changes.

The analogy I can give for compression is that of the engineer sitting at the console with her hands on the fader. When the audio rises above a certain level she lowers the fader - and therefore the volume - a certain amount for every increase in level.

This is why your song will be quieter.

And when the audio drops below that certain level, she moves the faders back to the original position.

Now that you understand that, here's how I can make your song louder:

The Five Basic Points Of Dynamic Range Compression

1. Threshold:

    This is the point above which the audio volume is decreased. (The engineer pulling down the fader). In the digital world this is expressed as negative number such as -10, or -15 dB. It's amount below the maximum level that digital audio is measured.

2. Attack:

    The time it takes to lower the volume (or how long it takes the engineer to pull down the fader) when the threshold is reached. This is expressed in milliseconds (ms).

    Short, or fast, attack times can generally be anywhere from 0 – 25 ms. Long, or slow, attack times are around 75 – 150 ms, or more.

    I’ll use longer attack times when mastering if I want to enhance the dynamics and add punch to a track. More on that below....

3. Ratio:

    Determines by how much the audio is decreased (how far the engineer pulls down the fader). Figures like 2:1, 4:1 etc. express the ratio.

    What it means is that - with, say, a 2:1 ratio - for every 2 dB increase of the audio input above the threshold, there is a corresponding 1 dB increase, only, of the audio output.

    The behavior of the compressor at this point is referred to as being non-linear. Below the threshold the compressor acts in a linear fashion, because the audio output is unchanged in comparison to the input.

    (It's a whole other story, of course, if the software is also emulating a tube compressor, but for now let's keep it simple)!

4. Release:

    Determines how fast the volume (or the engineer pulling the fader) returns to its original level once its below the threshold. This is also expressed in milliseconds.

    Short, or fast release times, can mean anywhere from 0 – 50 ms, while long or slow release times can be 100 – 200 ms, or more.

    I generally will use longer times when mastering to avoid distortion, for example.

5. Make-up Gain:

    This is where your songs get louder!

    The amount the audio is decreased above the threshold is often the same amount to increase the overall make-up gain.

    All compressors give some kind of visual feedback as to the amount reduction being applied and this is where to get a starting point for setting make-up gain.

    My ears, as always, are the final judge!

To continue with some more advance compression topics, click here.

Using Dynamic Range Compression In Mastering

If I use it when mastering, I aim for subtlety and transparency. But it depends - always - on the individual song. Sorry, there are no formulas! In most cases, I try to apply no more than around 2 dB reduction.

Like limiting, the gain reduction meter should ‘bounce’.

If I choose longer attack times (when coupled with the right threshold and release times), this lets more of the accents out before compression starts. When everything is in alignment, this can make your chorus, which is usually louder than the verse, more punchy, dynamic and strong.

Other times a song just needs a little 'glue'! With a low threshold and a still lower ratio setting (like 1.1:1 or 1.01:1), I can add some warmth if a song needs that.

So Where Do I Start With Dynamic Range Compression?

I start by asking and pondering another more important question:

  • What does your song actually need?

If you like to know personally, contact me for a free sample now.

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