FabFilter Pro-Q 4 review: The EQ That Does It All

If you’ve ever found yourself in a mix, tweaking an EQ plugin for hours — only to feel like something’s still off — then you know the struggle of balancing precision with musicality. Enter FabFilter Pro-Q 4: an EQ plugin that combines dynamic EQ flexibility with surgical precision.

For those familiar with Pro-Q 3, FabFilter’s earlier flagship, Pro-Q 4 builds on a strong foundation and adds several key upgrades. Pro-Q 3 was revered for its clean, transparent sound, powerful features, and intuitive interface, and Pro-Q 4 keeps all of that but supercharges it in several areas. The addition of more precise dynamic EQ controls, auto-gain, and an improved spectrum analyzer makes Pro-Q 4 not just a revision, but a real evolution for those who need precision, flexibility, and speed in their mixes.

The first thing that stands out when you open up Pro-Q 4 is how quickly it feels like an extension of your creative process. The user interface is intuitive, with colour-coded bands that help you visualise your EQ moves in real-time. This makes it incredibly easy to work with, especially when you're balancing a busy mix and need to dial in exactly the right frequencies. The learning curve is pretty minimal, even if you're new to EQ plugins.

But it’s not just the interface that stands out — FabFilter Pro-Q 4 sounds incredible. Whether you’re boosting high frequencies for a crisp vocal or cutting the low mids to tighten up a bass line, Pro-Q 4 delivers clean, transparent results with no unwanted phase distortion or harsh artefacts. The improvements over Pro-Q 3 are also noticeable, especially in how musical the boosts and cuts feel; and there’s an inherent smoothness to the way it seems to shape the sound.

The dynamic EQ functionality is now more intuitive and refined. A new Additive mode allows you to boost frequencies dynamically in the same way that you'd normally cut them, and there have been improvements to the compression and expansion algorithms as well as more advanced sidechain options and subtle tweaks to improve the threshold control.

Making Mixing Easier

One of the standout features of Pro-Q 4 is the auto-gain function, which automatically compensates for volume shifts when you’re making significant EQ changes. This simple, yet brilliant addition makes sure your levels remain consistent, even when you’re boosting or cutting large sections of the spectrum. It's an excellent feature that saves time and can help prevent potential mixing errors when you're focusing on EQ moves.

Pro-Q 4’s upgraded spectrum analyzer is now able to display spectral dynamics in real-time which allows you to see how frequencies evolve throughout the track, making it easier to identify problem areas like resonant peaks or low-end buildup that might only appear during certain sections. This level of detail ensures you're making dynamic adjustments with precision, allowing for more natural and transparent EQ moves. Very nice, indeed.

Streamlining the Workflow

Another thoughtful update in Pro-Q 4 is the Instance List, which simplifies managing multiple instances of the plugin in your session. Whether you’re hopping between tracks or adjusting EQs on different elements, the Instance List lets you quickly jump to specific instances without losing your place. It’s an efficient way to navigate complex mixes, especially when you’re working with numerous EQs across a session. No more searching through dozens of channels to tweak your settings - it’s all right there in front of you.

Equally useful is the EQ Sketch feature, which brings a more creative, hands-on approach to shaping your sound. This tool lets you visually ‘sketch’ EQ curves directly in the interface, making it quick and intuitive to dial in custom frequency adjustments. 

You can immediately draw and adjust your curves without having to fine-tune every detail manually, which can speed up the process of finding the right tone as well as a fantastic way to experiment with new ideas.

Pro-Q 4’s presets deserve a shout-out too - particularly, I found, for mastering. Over the years I’ve worked lots with mastering engineers, and have enjoyed watching mastering tutorials on YouTube to simplify the process a little - well-respected producers such as Streaky, for example, who often talk about ‘the smiley curve’ EQ as a good place to start if you’re trying to master something in a home recording environment.

Well, this plugin has some terrific mastering presets that are a nod to that theory and some: Dynamic Smiley Curve gives you an excellent starting point, and Supreme Transparency is terrific, designed for those who EQ using only 3dB/octaves and very gentle shelves. The Mix Mud Removal presets are also great for quick fixes.

The Ultimate Mixing and Mastering EQ?

If you’re looking for an EQ plugin that combines precision, musicality, and a clean sound, FabFilter Pro-Q 4 could well be the answer. Whether you’re making delicate surgical cuts or broader tonal shaping, Pro-Q 4 provides the tools you need without introducing unwanted artefacts or taking away from your mix’s natural tone. It’s versatile enough to handle everything from basic EQ tasks to advanced dynamic EQ for complex mixing situations.

The dynamic EQ alone makes it an essential tool for serious mixing, while the auto-gain and improved spectrum analyzer streamline the workflow, making mixing faster and easier than ever. If you’re a producer, engineer, or musician who wants an EQ that can do it all without breaking a sweat, FabFilter Pro-Q 4 should be at the top of your plugin list.