Mastering with Ozone 8: Compression

This blog post is part of a series on Mastering with Ozone 8 Standard. If you missed a tutorial, click on the topics below to catch up:

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

Ozone 9 Advanced, the latest version of iZotope’s mastering suite, offers even more powerful features — check out the guide here.

There are plenty of tutorials and articles out there about compression, what it is and what it isn’t. In this tutorial, we’re going to focus specifically on compression for mastering and how we can approach it as you tackle your own masters.


What does a compressor do?

A compressor reduces the dynamic range of a mix. This means reducing the difference between the loudest and softest parts of your mix. The tradeoff here is that, with a smaller dynamic range, you can push the mix louder by compressing.

That matters in mastering. Compression can do many other things, like make something more punchy, increase detail or make things sound fuller, but in mastering a compressor makes things louder.

Although mastering engineers use limiters to make mixes louder, solely using a limiter to do all the legwork will produce unwanted effects such as pumping and distortion. But splitting the work between a compressor and limiter will yield a more natural result.

Does the mix need compression?

The majority of the mixes these days come in so hot that a compressor is not required. Use your ears when you get a mix. If you find that the mix itself is already pretty compressed, adding mastering compression probably won’t help it much.

Make use of Ozone 8’s metering to see if you’re hitting target levels without additional compression.

How much compression do I need?

  • In truth, mastering engineers hardly use any compression. If they do, it’s at low ratios and high thresholds.
  • Here are some general guidelines if you want to use compression while mastering:
    • Start your ratio at 1.25:1 or 1.5:1. Going past a ratio of more than 2:1 is not recommended.
    • Set your threshold pretty high so that you’re getting at most 2dB of gain reduction.
    • Use your ears! If you apply compression and don’t like how it changes your master, take it out.
    • Keep asking yourself after every move – “Am I making the music sound better?”

Should I use multi-band or single-band compression?

In Ozone 8 Standard, you can use either single-band compression or up to three bands of compression. Here are some reasons why you’d choose one or the other.

  • Reasons to use multi-band compression:
    1. When you want to have control over different frequencies.
      • As you know, compressors react differently to different frequencies. For example, bass frequencies are longer in wavelength, and having a band to process the low-end without affecting the rest of the frequencies is ideal
      • With a multi-band compressor, you can set different attack, release and threshold settings for the different bands. You can divide the frequency bands into 3 or 4 bands (low, low-mids, mids and highs)
      • Because multi-band gives you the ability to set different settings for each band, you’re essentially tailoring your compression specifically for your mix.
  • Reasons to use single–band compression
    1. When you want to keep things simple and not over process.
      • With mastering, the number one rule is not to over process. Over-processing of a multi-band comp can easily make your master sound unnatural. I recommend only using a multi-band compressor if you really know what you’re doing.

Summing it Up

  • Compression can be a useful tool in mastering if your ears tell you that the mix needs it.
  • Make use of M/S dynamic processing in Ozone 8 to perhaps tame a vocal in a mix if you think it is too dynamic.
  • Work in moderation. Try not to over process and keep the gain reduction to no more than 2dB.

Next up, we take a look at limiting in Ozone 8 Standard.

October 5, 2017