Rupert Neve Designs 551 Inductor EQ Review: Hands-On With the New Plugin

The 551 Inductor EQ is Rupert Neve Designs’ first plugin released under its own name. It is also the only 500-Series EQ Rupert Neve himself actually designed. I tested it on a simple drum loop and on an EDM mixbus to see how it handles real sessions, not just a demo reel. This review covers the official release details, what happened in both tests, and whether the 129 dollar price tag is worth it.

551 Inductor EQ Review: The Short Answer

My take after testing it is simple. The 551 Inductor EQ gets you a good tone quickly. It holds up even when you push the highs harder than you should. I would recommend it to anyone who wants usable tone without staring at a spectrum analyzer for twenty minutes. At 129 dollars, the price feels fair for what it delivers. I see real use for it on individual tracks, and on a mix or mastering buss.

Want a repeatable process for finding the right EQ moves? Grab my free Mixing and Mastering Cheat Sheet. It includes my 7-step boost-and-sweep technique for hunting down problem frequencies before reaching for a character EQ like this one.

What Is the 551 Inductor EQ?

Rupert Neve Designs released the 551 Inductor EQ on September 15. Two other plugins launched alongside it, the Portico II Master Buss Processor and the 542 Tape Emulator. RND has collaborated on software for other brands before. This is the first time the company has released plugins under its own name.

The 551 is the only 500-Series equalizer Rupert Neve actually designed himself. It uses circuitry originally built for the Shelford Channel, with three bands inspired by some of his most prized vintage designs. Those bands work on set frequencies rather than a fully sweepable range, a bit like the focused approach behind an elliptical EQ. The plugin adds two things the original hardware does not have, true mid-side processing and input and output metering. McDSP helped develop it. It runs in Pro Tools, Logic, Cubase, Nuendo, FL Studio, Ableton Live, and Studio One, through AAX, AU, or VST3. It needs an iLok for authorization. The plugin costs 129 dollars, the same as the 542 Tape Emulator, while the Master Buss Processor runs 199 dollars.

Here is the full review:

First Test: A Simple Drum Loop

The first thing I noticed had nothing to do with tone. Bypassing the plugin does not change the loudness of the source. Plenty of plugins lean on a trick where inserting them makes the source louder right away, which tricks your ear into thinking it sounds better. The 551 does not do that, and I respect it for that alone.

Each band sits on a set frequency, and you find the one that works for your source. On the drum loop, 35Hz was the sweet spot. Boosting it by just one dB added real beefiness to the kick, closer to a musical, vintage-style push than a surgical one, the same spirit behind a Baxandall EQ. The mid band added body to the snare in a genuinely easy way. I pushed the highs harder than I normally would. That is usually where an EQ starts to crack and get harsh. The 551 held up well. After matching input and output gain, I had a tone I liked within a couple of minutes.

Second Test: An EDM Mixbus

On the mixbus, 35Hz did the same job it did on the drum loop, rounding out the low end nicely. I added around 6k on the mids and tried both 8k and 16k on the highs. Either one opened up the mix fast.

Fixed-frequency EQs like the 551 work differently than something like FabFilter Pro-Q4, where you have full freedom over the entire spectrum. I like both types of plugins. For most producers, though, an EQ that hides the full spectrum view and forces you to focus on what you hear is often the better tool. That philosophy is exactly what I teach inside Music Production Masterclass, listen first, look second.

Legacy System Support and a McDSP Clue

I do not own the hardware 551 or a Shelford Channel. This was my first time working with that circuit in any form. One detail stood out beyond the sound itself. The plugin runs on older systems, including High Sierra, which is what I am still running. That is a real accessibility win for mixing and mastering engineers who have not upgraded their systems in a while.

I also noticed the McDSP logo appear when I activated the license on my iLok. That suggests McDSP built the plugin engine itself, with Rupert Neve Designs supplying the circuit design and sound.

Is the 551 Inductor EQ Worth 129 Dollars?

Yes, for most producers. I would recommend it to anyone who wants good tone from their sources quickly, the same way I recommend building an original sound instead of leaning on a generic preset. It works both as a mixing tool on individual tracks and as a mastering tool across a full mix.

I already have a full toolbox, so I am not certain I will buy it myself. If it landed in my hands as a gift, I would genuinely reach for it more often than several tools I already own. My honest recommendation is simple. Get it and test it in your own sessions.

Key Takeaways

The 551 Inductor EQ is the first plugin Rupert Neve Designs has released under its own name, and the only 500-Series EQ Rupert Neve designed himself.
Bypassing the plugin does not inflate loudness, which makes an honest first impression compared to plugins that rely on a loudness trick.
A single dB of boost at 35Hz added real beefiness to a kick drum, and rounded out a full EDM mixbus in the same way.
Fixed-frequency bands push you to mix by ear rather than by looking at a spectrum analyzer, which suits most producers well.
At 129 dollars, it is a fair price for a tool that works on both individual tracks and a mix or mastering buss.

Baxandall EQ: another musical, character-driven approach to shaping tone.
How to Use an Elliptical EQ: another EQ tool built around a specific, focused job.
Sonnox Oxford Limiter Review: another hands-on gear review from my own sessions.
Hybrid Mastering: how tools like this one fit into a full mastering chain.
How to Avoid the Sample Pack Sound: why building your own tone by ear matters beyond just EQ choice.

Ready to Go Deeper

A good EQ helps, but knowing what to listen for is what actually makes a mix or a master sound finished. The Music Production Masterclass walks you through that entire process, ear first, from a raw idea to a finished, mastered song.

About the Author

Adrian Milea is a mixing and mastering engineer, music producer, and educator. He has more than twenty five years in the industry, including releases on Armada Music and features in DJ Mag. He teaches mixing, mastering, and the business side of audio production through his courses at adrianmilea.com.

Until next time, Stay Cool and Make Great Music,
Adrian Milea

What is the Rupert Neve Designs 551 Inductor EQ plugin?

The 551 Inductor EQ is a plugin recreation of Rupert Neve Designs’ 500-Series hardware EQ, the only 500-Series equalizer Rupert Neve designed himself, released as one of the company’s first plugins under its own name.

How much does the 551 Inductor EQ cost?

The 551 Inductor EQ has an MSRP of 129 dollars, the same price as the 542 Tape Emulator released alongside it, while the Portico II Master Buss Processor costs 199 dollars.

Is the 551 Inductor EQ good for mixing or mastering?

Both. It works well on individual tracks during mixing and across a full mix or mastering buss, since its fixed-frequency bands make it easy to shape tone quickly in either context.

What new features does the 551 plugin add over the original hardware?

The plugin adds true mid-side processing and input and output metering, neither of which is available on the original 500-Series hardware unit.

Does the 551 Inductor EQ work on older computers?

Yes. The plugin runs on older operating systems, including macOS High Sierra, which makes it accessible to producers who have not upgraded their systems recently.

Is the 551 Inductor EQ worth buying?

For most producers, yes. It delivers a usable, musical tone quickly without extensive tweaking, and its 129 dollar price is reasonable for a tool that works across both mixing and mastering tasks.