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Limiting and Compression:
What's The Difference?

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Limiting and compression.

Generally similar yet very different in their results, especially in the mastering stage.

What Is The Difference, Anyway?!

While compression may be one of the very early stages in my mastering chain, limiting is the second last step.*

And while similar to compression, the settings are more extreme:

  • With ratio - anything above 8:1 - is considered limiting.
  • Attack and release times are much, much shorter - 0 to 50 ms.
  • Thresholds are more higher.

The main difference, with limiting and compression, is I use limiting to put a cap on the maximum level a song file can reach. This creates a headroom gap. I then close this headroom gap, by raising the levels.

Yeah – Limiting Is Where Your Song Gets LOUD!!

If...that’s what you really want!

To make things perfectly clear, I’m talking about what's referred to as a brickwall limiter. While a standard limiter does a similar job, it doesn't necessarily catch all the overshoots.

This is important!:

To raise levels effectively and properly, never exceed 0 dBFS. That would cause clipping.

And unless we're working with 32 bit floating point files, clipping will introduce distortion.

Maximizing Levels The Right Way

Depending on the file, I can usually get 3 dB of gain right off the bat. But starting to push for more gain and more level can have a negative effect beyond a certain point.

To maximize the gain, I minimize the amount of work the limiter has to do. By skillfully applying things like equalization and compression beforehand, I can very often get another 3 dB of gain - for a total of 6 dB - if I need to.

Very often though, I never need to push that much. The perceived loudness increase, by a carefully applied chain before the limiter, gives me a lot of flexibility with final levels.

By doing just a little at the right place with the right tools, I can get a lot more out of the final master!

      *Less Processing

          **More Dynamics!

              ***More Power!!

Limiting and Compression: Two Schools Of Thought

There are two general approaches in the mastering chain:

  • Use equalizers, compressors, and any other enhancement devices, to achieve gain increase, while the mastering limiter is there only to prevent overs and prevent clipping and distortion.
  • Use the same tools but stay at unity gain (the song's original volume level) to do enhancement, while using the brickwall limiter to add the gain, whatever is needed, and prevent clipping.

I generally tend to favour the second method. This lets me hear how the actual enhancement contributes to, and improves, the final master whenever I solo the limiter, bypassing the previous effects in the process.

My Approach

With compression, my approach is less for gain reduction and more for either dynamic enhancement, or a general body or glue to the music.

This is a bit ironic: in order to enhance the rhythms in a pleasing and invisible way, I need to work on the more audible portion of the file - the RMS levels - to achieve that transparency.

I work on the audible portion with the goal of being inaudible...subtle.

With brickwall limiting, I’m working with transients. Many transients go by so fast as to be inaudible to the human ear.

By working on these inaudible parts of the file, I contribute a very audible, and not subtle, end result! Namely the very coveted loudness increase.

Invisible? Inaudible? Is It...Bouncing???

I find it useful, when working on these ‘inaudibles’, to keep my eye on the gain reduction meter on the limiter. I want to see it 'bounce'.

In other words:

  • the gain reduction meter should return to zero frequently.
  • It should always be dynamic.
  • It should always be ‘flashing’ - never solid.

Of course, my ears will tell me when the meter is solid before I ever look at it!

And as long as that meter is bouncing, and verifies what I’m hearing, I can push that gain dB increase as much as you need it.

Of course that being said, you should...

Remember This About Limiting And Compression:

  • 'Loud' doesn't make a song better.
  • Too much and your listeners will tune out and turn off...

Then you'll - limit - your audience!

Then where will you be?

Find out the difference the proper use of limiting and compression can make to your music: click here!

*I've referred to limiting as the 2nd last step in the mastering chain.
So what is The LAST Step?

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