8 of the Best Mastering Plugins on the Market

Learn about popular mastering plugins like FabFilter's Pro-Q 3 EQ, Oeksound's Soothe dynamic EQ, and more.
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Mastering is the process of formatting a song for distribution. With digital audio workstations (DAWs) being more accessible than ever before, many musicians and producers have taken an interest in mastering. While there’s a substantial benefit to having a professional master your project with a fresh set of unbiased ears, you may be interested in learning about mastering yourself; a big component of mastering includes the tools you use. This plugin roundup is going to cover 8 of the best mastering plugins on the market.

Some of the most fundamental mastering tools include EQs, compressors, saturators, dynamic processing devices, stereo imagers, limiters, and meters. A mastering engineer must know how to use these devices to work effectively. If you’re not yet familiar with all these types of tools, I suggest you check out “Mastering Demystified” by Justin Colletti; this is one of the best mastering video courses that I’ve come across online, and it’s well worth the small investment.

It’s true that you can mix your music using stock plugins, but mastering engineers require specialized tools. Part of the reason for this is that they’re usually working with mixes that have been sent to them as a stereo track. Instead of opening up a mix session to turn a kick down 2 dB, they need to resort to other methods that will not only fix the issue but preserve the quality of the overall track.

Every plugin company mentioned in this list has had sales in the past, some offering over 80% off their products. Be patient and keep an eye out for sale announcements on the social media pages of these plugin manufacturers; you should be able to pick up a majority of these mastering tools at a heavily discounted price. Check out "The Ultimate List of Plugin Companies" to see which plugin manufacturers are worth keeping an eye on.

8. FabFilter Pro-Q 3 ($179)

A picture of FabFilter's Pro-Q 3 plugin.

I mostly use stock or analog-modeled EQs while mixing, since I’m either looking for convenience or color at that stage in the production process. Things change a little bit once I get around to mastering either my own music or the music of others. At a mastering level, I want a digital EQ full of features, with the ability to perform surgical processing; this is where the FabFilter Pro-Q 3 steps in.

This EQ offers up to 24 bands, 9 different filter types, linear phase, zero latency, and natural phase modes, the ability to toggle bands into dynamic mode, per-band mid/side processing, full surround support (up to Dolby Atmos 7.1.2), the ability to solo bands, optional auto gain, a customizable spectrum analyzer, and a resizable GUI.

There’s a feature called Spectrum Grab included with the Pro-Q 3 that automatically identifies peaks for you and allows you to create new bands at resonant frequencies. I find this to come in handy quite often since it prevents the need to go frequency fishing. FabFilter’s Pro-Q 3 offers plenty of surgical processing options, making it ideal for mastering purposes.

7. Oeksound Soothe (149 €)

A picture of oeksound's soothe plugin.

Soothe is a spectral processor for suppressing resonances in the mid to high-frequency range of mixes. When the different elements of a song sum together when they reach your stereo bus, specific harmonics can sum together to create resonant frequencies that unpleasantly stick out of the mix. Soothe offers a solution to this common mastering problem, and also has several useful mixing applications.

This plugin can tame vocal sibilance, fretboard noise on acoustic guitar, whistling from cymbals, and overly bright electric guitar and piano tracks. I’ve had soothe rescue many recordings that not many other tools could have saved. This is absolutely a specialty plugin, but one with a wide range of applications. Whether you’re a mixing or mastering engineer, soothe will provide tremendous value, on top of an easy-to-use interface.

Soothe made its way into “4 Essential EQ Techniques to Get Clean Mixes,” which touches on some mastering EQ tips as well. Read the full article for more information on cleaning up your mixes and masters.

6. UAD SSL 4000 G Bus ($299)

A picture of Universal Audio's SSL 4000 G Bus plugin.

The UAD SSL 4000 G Bus compressor offers a lot of punch and does a great job of preserving the transient information of mixes, while effectively gluing together the components that make up the song you’re working on. Most of the characteristic sound that the SSL 4000 G Bus offers is due to the feedback-style approach to compression that its analog counterpart takes.

In his article on “Feedback Vs. Feed-Forward Compression: The Differences You Need to Know, Rick Slater of SonicScoop explains that “The SSL bus compressor is designed so that faster attack release times will deliver smaller amounts of reduction while slower settings provide lots more, making for more even gain reduction as you cycle through the attack settings.” The SSL 4000 G Bus is perfect for Pop, Country, and Folk songs; it does a great job of maintaining the articulation and clarity of tracks.

If you’re looking for a bit more color, a strong alternative to the SSL 4000 G Bus is the Vertigo VSC-2 ($299). Like the SSL 4000 G Bus, the Vertigo VSC-2 is a VCA (voltage controlled amplifier) compressor, but instead of providing crisp compression, it adds an often-desirable thump and roundness to mixes. I particularly like the sound of this compressor on Hip-Hop and grungy EDM tracks.

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To learn more about compression, and an assortment of other recommended compressors, check out “The Ultimate Guide to Compression.”

5. FabFilter Pro-L 2 ($199)

A picture of FabFilter's Pro-L 2 plugin.

The FabFilter Pro-L 2 is a true peak limiter that is loud, transparent, and equipped with loudness metering. Everyone and their grandma uses this limiter. While you may be hesitant to jump on the Pro-L 2 bandwagon, you’re going to want to get over that feeling fast because it’s popular for justified reasons.

This limiter contains 8 different limiting algorithms, real-time level display with peak gain reduction levels, 32x linear-phase oversampling, true peak metering, surround support including Dolby Atmos 7.0.2 and 7.1.2, a DC offset filter, external sidechain triggering, Unity Gain for accurate monitoring, and an Audition Limiting option. The Pro-L 2 offers loudness metering with support for the EBU R128, ITU-R BS.1770-4, and ATSC A/85 standard. There are also various dither and noise shaping options.

If all of this technical mumbo jumbo doesn’t make much sense to you, that’s alright. In layman’s terms, the Pro-L 2 offers many more features than you likely require, and is probably capable of handling all your limiting needs. With the Pro-L 2, you should have no trouble formatting your songs for streaming services, CDs, and even vinyl.

In the following video, I demonstrate how to use some of the Pro-L 2's advanced features to optimize the quality of your music.

4. Sonnox Oxford Inflator (£ 115)

A picture of Sonnox' Oxford Inflator plugin.

Perhaps one of the most mysterious plugins I’ve used is the Oxford Inflator by Sonnox. It allows you to create louder mixes, and add apparent dynamic range to previously clipped signals. The strange thing about this plugin is that it doesn’t apply compression to your audio signal, which begs the question, “How does it make your music appear louder?”

According to the Oxford Inflator user manual “The Inflator process functions by changing the relative probability of samples in the programme material such that there is a greater probability of larger values than the original signal. The Inflator does not employ signal compression, so there is no ‘pumping,’ dynamic level change, loss of presence or flattening of percussive attacks. The full dynamic information of the music content is largely preserved despite the increase in average modulation density.”

With the Effect level on the plugin set to maximum, it will entirely avoid output overloads. This means that you can apply the Oxford Inflator post-limiter to squeeze out that tiny bit of extra loudness from a song if necessary. Be careful when using this plugin because a little goes a long way. If you’re not cautious, you can easily over-brighten your track, so be sure to A/B this device for optimal results.

3. iZotope Insight 2 ($199)

A picture of iZotope's Insight 2 plugin.

As far as all-in-one metering plugins go, iZotope’s Insight is great for both music production, and post-production work involving dialogue. It contains your expected loudness, level, sound field, and spectrogram meters, with the addition of an intelligibility module that helps you set dialogue levels appropriately.

You can place the included iZotope Relay plugin on any track in your DAW, which will allow the track to be viewed in the Intelligibility Meter and on the Spectrum within Insight 2. This will enable you to compare a single dialogue or vocal track to the rest of your mix.

Insight has plenty of visual customization options which allows you to tailor the plugin to your specific needs; you can toggle off the modules that you don’t need and easily resize the entire GUI to fit your screen.

I use a separate monitor dedicated solely for meters when I’m working on music. My default session templates contain an instance of Insight 2 on the master bus, which allows me to check on things like phase coherency starting during the recording process, right through the mastering process. Insight 2 contains all the types of meters mentioned in "6 Mastering Meters You Need to Learn How to Use," making it a great all-around mastering meter.

2. ADPTR AUDIO Metric AB ($199)

A picture of ADPTR AUDIO's MetricAB plugin.

ADPTR AUDIO’s Metric AB plugin allows you to compare your mix to a reference mix, in multiple different ways, by clicking on a large A/B button. Many people don’t use reference tracks effectively, which is mostly due to the inconvenience of having to match loudness levels and haphazardly A/B the data presented by different meters. Metric AB offers a solution to this problem by making the process of using reference tracks quick and easy.

A significant key feature is the loudness match button, which automatically matches the reference track’s loudness with the loudness of your source material. Going beyond this, Metric AB provides 5 detailed analysis and metering modes, which include a spectrum analyzer, phase correlation meter, stereo imager, dynamics meter, and loudness meter. Each meter allows you to either overlay the source signal with the reference track or compare the two side to side; this is the big selling point for this device.

You can load up to 16 reference tracks into Metric AB. I have an assortment of reference tracks that span across different genres saved as a preset, but if 16 reference tracks aren’t enough for you, you can save different presets containing reference tracks for different genres. Metric AB has earned a permanent spot near the end of my mastering chains, and I can’t imagine working without it now.

1. MeterPlugs Loudness Penalty ($49)

A picture of MeterPlugs Loudness Penalty plugin.

For the past while, loudnesspenalty.com was what audio engineers were using to find out if YouTube, Spotify, TIDAL, Pandora, and Apple Sound Check were going to attenuate the level of their songs once uploaded. MeterPlugs has turned this website into a plugin, allowing you to perform this loudness penalty check inside your DAW. This removes the need to export multiple versions of your song and upload them to a website, which is an excellent time-saver.

The main features that Loudness Penalty boasts include the ability to optimize your music’s online loudness, preview how your music will sound online, pinpoint loudness pain-points, discover when it’s possible to turn your music up, demonstrate to clients how streaming services affect loudness, and avoid having to resort to loudness trial and error.

Loudness Penalty finds itself right at the end of my mastering chain. Placing this plugin after Metric AB allows me not only to check how my own mixes will be affected by the loudness penalty but how my reference tracks are affected as well.

Best Mastering Plugin Bundle: iZotope Ozone 8 Advanced ($499)

A picture of iZotope's Ozone 8 Advanced mastering plugin bundle.

If you’re looking to get the best value for your money, iZotope’s Ozone 8 Advanced mastering suite is unbeatable in my opinion. It includes 12 essential mastering tools that will help you get started mastering music. The included modules are called Spectral Shaper, EQ, Dynamic EQ, Post EQ, Maximizer (with IRC IV and new IRC LL), Imager, Exciter, Dynamics, Vintage Limiter, Vintage Tape, Vintage EQ, and Vintage Compressor.

Whether you’re looking for a modern sound or more vintage sound, Ozone 8 will be able to deliver. It’s entirely possible to master entire tracks with this mastering suite and hear professional results. iZotope also puts out free educational content that makes use of their mastering tools, so learning how to use their products is a relatively painless process.

Ozone 8 allows you to A/B your masters against reference tracks, making it a decent alternative to Metric AB. Many of Ozone 8’s modules can perform processes similar to the plugins mentioned in this list, but their range of features may not be quite as extensive.

If you’re mastering your own music and have complete access to your mixes, iZotope’s Ozone 8 Advanced may be all that you need; most issues you run into at a mastering level should be fixed in the mix. When you work as a mastering engineer, you don’t always have access to a client’s mix so you may require more surgical processing. In this case, I think the individual plugins mentioned in this list may be worth your while.

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