Mastering 101: Limiting

Limiting is the step where you get your mixes up to commercial loudness to compete with the other masters out there.

This post is the fifth article in our introductory guide to mastering. If you’ve missed an entry, click on any topic below to catch up:

  1. What is mastering?
  2. Signal flow & metering
  3. EQ
  4. Compression
  5. Limiting
  6. Preparation

This week, let’s explore the topic of limiting.


Limiting is the last process in your mastering signal flow. It’s here where you get your mixes up to commercial loudness to compete with the other masters out there. Here are a couple of tips to get you started with limiting.

Target Levels

meter

In part two of our mastering series, we talked about the importance of setting target levels by using VU meters. This is an essential step to help guide you towards reaching the loudness you’d like to achieve.

Here’s a quick summary of the different target levels needed for the different genres.

  • Classical 0 VU = -18 dBFS
  • Jazz 0 VU = -9 dBFS
  • Pop 0 VU = -8 dBFS 
  • Aggressive pop / hip hop = -7 dBFS

When you’re limiting and getting your mix to a target level, note that if your VU meter is hitting around 0 VU, you’re more-or-less hitting the desired loudness. If you go beyond 0 VU and into the red, you’re pushing the loudness of your master and making it less dynamic.

Setting up the limiter

Every limiter has almost identical controls such as input gain, output gain, attack, release, and gain reduction, and it’s worth going through how we can apply these in a practical fashion. For the purposes of this post, I’ll be using one of my favorite mastering-grade limiters, PSP’s Xenon.

input output

Input & output gain
Output gain: The output gain level is the limit that your audio signal doesn’t cross. In practice, you would want this level to be below 0 dBFS to prevent any digital clipping. Before you start tweaking any settings, I recommend that you set the output gain limit to somewhere between -0.2 dBFS and -0.02 dBFS.

Input gain: The input gain is the amount of gain that you’re feeding into your limiter. The more gain, the more gain reduction, and the louder your master will be. To start off, slowly increase the input gain of your limiter until you reach your target level. You might need about 4-7 dB of gain reduction to achieve this.

attack release

Attack & release
Attack: Try to set your attack time to be as short as possible, without loosing impact.

Release: The release timing is key in limiting. A long release time will cause a loss in level and pumping. Too short a release time will cause distortion artifacts. If your limiter has an auto-release setting, consider using it so that the limiter will be able to compute the best release time for your track.

link control

Link control
The link control setting on your limiter decides if the plugin limits both channels equally (link control at 100%) or totally independently (link control at 0%).

With a setting of 100%, the limiter preserves the solidity of the bass and the left/right balance of the mix. When the setting is unlinked (link control @ 0%), your master will sound wider and louder, but it thins the bass and changes the L/R balance.

A good compromise would be to set the link control at 50%. However, if a mix has a lot of L/R interplay and difference, leave the link control to a 100%, as you wouldn’t want to mess with its stereo image.

Gain reduction

gain reduction

To reach your target level, you’ll find that you need at least 3 dB of gain reduction. The more gain reduction you have, the more you’ll hear the artifacts of your limiter. In a good master, you don’t want to hear the limiter working, while still achieving desirable loudness. Therefore, ideally the gain reduction limit you should have on the limiter should be no more than 2.5 dB. But how do you do that?

Clipper

The clipper

In this day and age where the loudness wars are still prevailing (it’s getting much better though, thanks to loudness normalization standards in streaming) and clients want masters loud, professional engineers often use a clipper to add extra gain to their master. A clipper ‘clips’ the mix to add apparent loudness to the master. The best one I know so far is Kazrog’s KClip.

How to use it:

  • Push the input gain of your limiter until you achieve your target level.
  • Take note of the amount of gain at the input stage (for example, 8 dB).
  • Now load up the clipper before your limiter and split the difference between the two.
  • You now should have 4 dB of gain on the clipper and 4 dB of input gain on the limiter, allowing you to have less gain reduction on your limiter while still achieving the same loudness as before.

This guide should give you a good starting point to start limiting – just remember not to over-process anything.

Lastly, let’s take a look at preparing your master to be sent out to labels / distributors / digital content providers.


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February 29, 2016

Reuben Raman Product Marketing Manager at Splice