There are so many limiters on the market, and they all have their own unique technologies and DSP, but which is best, and why do they sound different, and ultimately when and why should you use one limiter over another?

Understanding how tools help us push those boundaries—and when I came across the patent for the IRC (Intelligent Release Control) used in the Maximizer, it's like nothing I've seen before, and it's going to help us answer why this limiter in Ozone is so revered.

So, let's think of your typical limiter: you're setting it up, you set the release time too fast, and it's going to introduce audible distortions; you set it too slow, and it's going to start to pump against the music.

The release is what makes the difference, and there's a history of dynamics processors with auto-release.

The ARC in Waves limiters vary the release times through calculating the difference between constantly traced peak and RMS values of a signal. Then you go back further: auto-release modes on hardware gear operate through a series of time constant circuits connected together, and each of them will have different discharge values, where the top capacitors are arranged to have a very fast release time and the subsequent capacitors slower and slower.

And what that does is it allows the release time to vary based on signal strength.

That's exciting in and of itself, and I can make some videos on that later, but what makes the Intelligent Release Control in the Maximizer different?

Well, it relies on psychoacoustic modeling to dictate how the release values of the limiter are manipulated, and that might sound pretty techy, but let me break it down for you, and then I'll share with you an example of how I choose and when I choose to use the IRC limiter over another.

Before we get stuck into it, don't forget to smash that like button.

Subscribe, and let's get to the juicy bits here. I've got the patent, which I've linked down below, and it's figure two we're going to look at to start with.

Let's start with amplitude envelopes. So, after it takes an input signal, it will generate six to eight individual attack and release times and construct them in parallel with one another—some with a fast attack, fast release; fast attack, slow release; and various combinations all in between.

Then, that processed signal is normalized and subtracted from the original input signal. What that does is it provides a delta signal with the resulting artifacts for each of those envelopes.

Now, while that's happening, it's also creating a masking threshold, and that masking threshold is created from the input signal, and it's based on an FFT ear model in PEAQ's paper, Perceptual Evaluation of Audio Quality.

What that returns is a masking threshold specific for that input signal, and that is used to calculate a relative distortion score by comparing each of the amplitude envelopes' delta signals to the masking threshold.

And then what the IRC algorithm does, it selects the most aggressively limited signal whose distortion score is below the masking threshold.

That's a lot to take in, but on top of that, it's also doing it continuously to the incoming signal, so it's not set and forget; it's constantly recalculating and assessing what setting is best for that audio to avoid distortion.

Now, that's how the IRC algorithm works, and it's a lot to process, but in the field, how do I use the IRC maximizer, and when do I opt to use FabFilter Pro-L 2?

I'll tend to use the IRC maximizer on material which contains a lot of variation from one section to the next between these various sound qualities if lots of low frequencies or subs are being introduced and taken away, if RMS values are changing very drastically in the same sections and also transient and punchy sections to sustained and open sections, that's where I find the IRC Maximizer does a great job and it manages sparse and diverse material like no other limiter does.

In this example, I overtrack which embodies all of these sound qualities and what I want you to listen for is how the Maximizer manages it in such a transparent way in opposition to Fab Filter Pro-L 2.

What I've had to do is to match these up, I've had to manipulate the attack time to be relatively fast but still open enough that it is as equally aggressive as the IRC one.

So, giving me the same amount of loudness, I've actually had to drive the compression on the FabFilter Pro-L 2 a little bit more, an extra half a dB, in order to match its overall loudness.

What I want you to do is, I'm going to loop these sections—can be two bars of lots of sub and then two bars of lots of open tone—and you're going to hear how the Pro-L 2 ends up distorting those subs when they come in because it can't manage to manipulate its release time dynamically with the material.

Now, you can definitely hear as soon as that sub-bass comes in, the FabFilter Pro-L 2 just starts breaking up. You can hear these little crackles and that's because it can't adjust its release time for the material appropriately, whereas the IRC Maximizer does it beautifully.

That said, there are still instances where I'm going to use FabFilter Pro-L 2 over the Maximizer. You see, FabFilter Pro-L 2 has a unique clipping feature for some of its modes when setting the attack time, and I go into full detail on this in this video here, because it's a great tool for crafting slapping pop or EDM tracks which are consistently high energy and have a lot of repetition in the choruses and verses.

With that said, I hope you've enjoyed the video, and if you've enjoyed this, I know you'll enjoy the FabFilter Pro-L 2 one as well.

Ozone Maximizer IRC mode, the Reason Why It Sounds BETTER Than Other Mastering Limiters?🙂

Hello. I'm Nicholas Di Lorenzo. I'm a mixing and mastering engineer and owner of Panorama Mastering Studio in Melbourne, Australia. I’m an Italian-Australian. born and raised in Melbourne.

This channel is for anyone involved in the music making process, artists, engineers, producers or musicians.

To stay up to date, hit the "bell" icon for alerts as I release videos weekly on all things audio, mixing, mastering and industry.

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Want to learn more about what I do?
https://panoramamastering.com.au 
@Panorama_Mastering

Ozone Maximizer IRC mode, the Reason Why It Sounds BETTER Than Other Mastering Limiters?🙂

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