When it comes to EQ, has it all been done before? Three Body Technology thinks not with its Kirchhoff EQ. This new uber-skulptor aims to be even more fabulous than the market leaders, offering classic EQ models with ‘does everything’ functionality. With so much on offer, we put it to the Experts…

Those in audio circles love nothing more than to discuss the virtues of different EQ types. On the understanding that the biggest factor in the use of any EQ is still the user, there is nonetheless plenty of room for the tool in question to have a big influence of its own on the sound. EQ can be grouped by several different characteristics, but taking any hardware versus software considerations away, the world of EQ has arguably settled into two MOs that are recognisable to most.

The Classics

Comprising original design analogue hardware or software ‘clones’, these EQs draw from decades of circuit design, beginning with classic units that while technically imperfect, brought character and musicality. Later refinements introduced more precise tools with improved technical performance. These can be in the form of the original units themselves, or found in a number of hardware or virtual recreations that strive to bring the musicality and desirability of their progenitors.

Moving On

Advances made in digital hardware and software EQs have eschewed some of the inherent limitations of an analogue design. Along with improved audio performance, the shaping possibilities offered by these tools have brought digital-only features, with innovations such as linear-phase equalisation, or constant bandwidth performance at extreme boost or cut.

One of the most transformative workflow boosters of digital EQ is the vastly expanded visual feedback it affords. This has been so transformative in the studio as to see many an engineer have those moments going to ‘look’ at a response curve or analyser on their conventional EQ that isn’t there!

Three Body Technology Kirchhoff EQ

Overview

Three Body Technology describe Kirchhoff EQ as the “ultimate EQ plugin with superb dynamic processing and vintage models”. Despite its distinctively digital DNA, the audio plugin actually boasts nine Vintage Equaliser models, along with customizable GUI themes. They continue:

Kirchhoff-EQ is an ultimate 32-band parametric EQ plugin built for all critical professional applications. It has refined sound quality, analogue-matched curves, 15 filter types with continuously variable shape and 32 vintage EQ types modelled from realworld devices. The built-in dynamic processing functions are highly flexible and have ultra-low distortion. All these push Kirchhoff-EQ to a next-generation standard.

Under The hood

Interestingly, Kirchhoff EQ employs what Three Body Technology refer to as their Robust Nyquist-Matched Transform. This aims to address the issue of digital EQ ‘cramping’ resulting from the inherent ceiling imposed by an EQ’s internal sample rate. In practice this should make for a more analogue-like experience, where frequency response drops off gradually. Kirchhoff-EQ boasts this approach on all of its filter types.

Three Body Technology also go into some detail about their Psychoacoustic Adaptive Filter Topologies on their blog, however these can best be summed up as filter structures that change dynamically to provide the ‘best fit’ that changes with frequency.

Specs And Feature Highlights

15 unique filter types featuring:

• low pass, high pass, band pass: continuously variable from 0 dB/oct to 96 dB/oct

• Bell, notch: continuously variable from 12 dB/oct to 96 dB/oct

• Low shelf, high shelf, tilt shelf: continuously variable from 6 dB/oct to 96 dB/oct

• Flat tilt and flat top

• Sword: has sharper slope than bell, specifically designed to "dig" out resonances

• Brickwall low pass, brickwall high pass, allpass low and allpass high

• Continuously variable filters slopes The slope of most filter types can be continuously changed from 0 dB/oct, 6 dB/oct or 12 dB/oct up to 96 dB/oct. Supports non-integer values such as 9.5dB per octave

• Zero-Latency/Analogue/Linear/Mixed Phase Modes. The phase mode of Kirchhoff-EQ is switchable between zero-latency mode, analogue mode, linear phase mode and mixed phase mode

• Flexible Dynamic EQ Functions which can be applied even to vintage models

• Two-Way Threshold Control In Kirchhoff-EQ: the "Above" stage works as a compressor or upward-expander, and the "Below" stage works as an expander or upward-compressor. For example, you can raise the signal below the threshold AND compress the signal above the threshold to "stabilise" a band

• Highly user-customizable GUI and controls to change the overall look of Kirchhoff EQ and customise mouse to invert up/down behaviours

In Action

See some of Kirchhoff EQ’s unique features and hear it in action in our video. We explore its continuous filters and shapes as well as its comprehensive monitoring and level matching capabilities.

Expert Panel - Hit or Miss?

In every Expert review we ask three of our team of contributors to give their first impressions of the product. We ask them to give the product a hit or miss, based on factors such as originality, innovation, usefulness, quality and value for money. For each hit the products gets an Expert Award. One hit and it gets our bronze award, two hits gets silver and for a hit from all three of the panel it gets a coveted gold award. Of course if there’s three misses, there’s no award.

Luke Goddard On Three Body Technology Kirchhoff EQ

With the ever expanding complexity of new audio processing tools, the engineer needs to step back and ask one simple question: will this tool make my mixes better? Being able to cut through the noise and establish exactly what needs to be done is key to employing the right tools for the job. I would argue that the minutiae on offer in some modern tools might detract from the aim of getting the mix right in a broader context. After all, do billions of people follow an artist because they connect with the music, or is it because of forensic EQ moves that can never translate to most listeners?

All that said, when everything is right, there is still room for using a tool such as Kirchhoff EQ to get the best possible outcome on the understanding that lots of well-loved mixes could have been even better. That alone is why the sheer amount of time spent and expertise shown by developers continues to drive the sounds made by those who demand the very best.

For me, Kirchhoff EQ falls fairly and squarely into that category, with Three Body Technology’s own EQ ideology surely being “make an EQ that is as good as it can technically be”. In terms of sound, I’m a firm believer that almost any EQ in the right hands will sound good- prepare to un-hear a lot of recorded music up until this point otherwise. In terms of technical brilliance, I think Kirchhoff EQ have achieved it, and if you have the time to explore its near-bottomless functionality, tweak heaven (or hell) awaits. HIT

Steve DeMott On Three Body Technology Kirchhoff EQ

I will start by saying that after a week and a half of testing, I am now using Kirchhoff as my everyday EQ.

What I absolutely love about this EQ is how great it sounds, no matter how I use it. It can be musical or surgical. And the 117-bit processing option is unreal in the right circumstances. On a lot of the acoustic music I do it makes a very noticeable difference to the sound. On the heavier/denser rock mixes I can’t say the difference is as noticeable, but it is there. To me, what I sensed when I engaged the 117-bit mode was added dimension & clarity, with a smoother high end that really let you add air to a mix without it ever even bordering on harsh.

The other feature I love is the analogue modelled EQ settings. The Vintage Tube setting became a favourite of mine (using the “analogue” phase mode setting). I was easily able to pull off the Pultec low-end trick, as well as my Pultec “boom & sizzle” setting (adding a small low & high boost to a 2-bus to add width & clarity). These filter settings really pushed Kirchhoff EQ over the top for me, giving me those familiar responses alongside the very adaptable native filter type options.

My one nitpick is the installer. It requires you to right-click > open on a Mac to bypass the security warning. I spoke with Kevin at Three Body Technology & he did say they were working on a registered/verified installer for Mac that would negate that need. So, while a small knit, it is being addressed.

My verdict: this is a definite hit for me. HIT

Nathaniel Reichman On Three Body Technology Kirchhoff EQ

A number of years ago, I did an EQ shootout and found that most plug-in EQs sound the same, with the exception of a couple that sounded much better and smoother on top. DMG Audio’s Equality was one of the smooth sounding winners back then, and I was eager to hear how Kirchhoff stood up in comparison. I was very pleased to find that it matches the sound of Equality. In fact, it matches so closely that the two of them null to -54db with the same settings and modes (even with “117bit mode” on or off). I put Avid’s Channelstrip up as a control, just to make sure I wasn’t fooling myself. Sure enough, Channelstrip sounds as screechy and ringy as it always has, the null failed and the sound was starkly different from Equality and Kirchhoff.*

In addition to sounding great, Kirchhoff has the open-design interface that FabFilter popularized, and it has many more bands than my beloved Equality. On the other hand, the out-of-the box Eucon mapping is not well thought-out. We do have custom maps on our Eucon surfaces these days, but I’m always a little disappointed when a manufacturer doesn’t at least make one default layout that puts my knobs for each band in predictable places. And the other disappointment with Kirchhoff is efficiency. One hundred instances at 96k on my Mac Studio is about 16-17% system usage compared to 10-11% for Equality. Finally, this plug-in appears not use iLok. This is a big drawback. Having plug-ins that are non-iLok is a logistical headache when moving mixes. All told, this is an excellent piece of software, and if you haven’t purchased a high-end EQ yet, this might be a great choice. For me it’s a miss because it only matches the competition instead of beating it, but hats off to Kirchhoff for the serious work. MISS

*I’m being a little unfair because Avid Channelstrip’s underlying code dates back to an early Euphonix digital console that had much less CPU power than we have these days. Nevertheless, lots of famous EQ plug-ins today sound the same as Channelstrip to my ears.

Kirchhoff EQ gets an Experts Silver Award.