Mäag Audio Magnum-K review

Turning a flagship rackmount channel strip into a software plugin for a fraction of the price

  • $299

MusicRadar Verdict

The miracle of software emulation gives every producer the chance to get their hands on Mäag’s incredible channel strip.


  • +

    Brilliant and innovative design.

  • +

    K Comp works a treat.

  • +

    Magnum Comp is super clean, and its Range control is useful .

  • +

    EQ2’s Air Band is always a winner.


  • -

    Unresizable interface.

  • -

    No bypass for Magnum Comp or EQ2.

  • -

    Non-literal parameter values.

MusicRadar's got your back Our team of expert musicians and producers spends hours testing products to help you choose the best music-making gear for you. Find out more about how we test.

Developed by brainworx, Magnum-K is a stereo plugin emulation of Mäag Audio’s dynamic-EQ-incorporating single-channel strip (see Magnum Opus for the back story). 

Both the hardware and software versions are remarkable for a couple of reasons. First, Magnum-K’s architecture brings together two very different compressors, an unusual two-band EQ and a limiter. Second, Mäag made its name in EQ, and this is its first ever compressor. 

Apart from the enormous difference in price and the ability to run as many of them as your Mac or PC can handle, other advantages presented by the plugin (VST/AU/AAX) over a pair of the real things include mid-side operation, stereo manipulation, dry/wet mixing and metering. So, even if the software Magnum-K isn’t 100% identical to its hardware counterpart (and we must confess, we don’t have the latter to hand for direct comparison), any discrepancies should hopefully be more than made up for by its affordability and convenience. And bearing in mind that it’s owned by Mäag themselves, we would expect those discrepancies to be minor at worst anyway. This isn’t a company known for compromising with their emulations, as proven by the superb EQ2 and EQ4. 

K class 

The plugin certainly looks the part, represented graphically as either one or two photorealistic Magnum-Ks, depending on whether the mono or stereo version is loaded, with all the software- exclusive enhancements in the separate ‘brainworx’ unit at the bottom. With the stereo version, the two main units handle the Left and Right channels, or Mid and Side if the M/S button is engaged, and can be linked for mirrored control (ie, adjusting a parameter on one changes it equally on the other) if required. 

At the start of the chain, the Input Attenuation and Input Gain knobs offer up to -12dB and +12dB of starting level adjustment. After that, the signal hits the main compressor, a supremely transparent ‘optical’ circuit that Mäag have dubbed Magnum Comp. Just as its quasi-magical Air Band makes for a powerful extension of conventional high-shelving EQ, we’re pleased to report that the company’s first ever compressor also has a nifty trick up its sleeve in the shape of the Comp Range knob. This limits the amount of gain reduction applied to 4, 8, 12 or 16dB, making it a set-and-forget solution for preventing over-compression, regardless of ratio. The available Ratios range from 1.3:1 to 13:1, while the Attack and Release times go from 5-200ms and 100ms-1.2s respectively, and a sidechain filter takes the lows out of the detection circuit at 40, 80, 120 or 220Hz, or can be set to receive an external keying signal. The Threshold knob is ‘inverted’, applying more compression the further clockwise it’s twisted. 

Magnum opus

The hardware Mäag Magnum-K on which the brainworx-developed plugin is based launched two years ago to a rapturous reception. The driving concept behind it is actually more than 35 years old, originating in Mäag founder and audio engineer Cliff Mäag’s invention of an automatic alternative to manually riding the 2.5kHz band on his console EQ in order to take the harshness out of vocals, brass and guitars. 

By combining the control and gain reduction circuitry of a compressor and a single-band EQ all those years ago, Cliff effectively created a dynamic EQ that targeted only the upper midrange, making his mixing life considerably easier. 

2017 at last saw the integration of that circuitry - which was given the name K Comp - into a dedicated device, to which was added a further broadband compressor with a Range control (quite a rarity), and a slightly tweaked Mäag EQ2 module, with its famous Air Band for high frequency shelving all the way up to 40kHz. 

Priced at well over two grand for a single mono channel, the Magnum-K is obviously out of the reach of most producers. Even if the plugin isn’t 100% identical, sonically, its affordability and convenience handily make up for it. 

Interestingly, the compressor is also switchable between feedback and feed-forward routing, the second option taking its sidechain signal before the gain reduction stage and thus being much more aggressive than the first. 

Next in the signal path, K Comp comprises nothing more than an In/Out switch and another Threshold knob for setting the input level at which further compression is applied around the 3kHz frequency range. Crank it up and hear those abrasive high-mids melt away. 

Breathe in the air 

The EQ2 section houses two boost-only EQ bands and runs in parallel to the serial compressors, so it can be applied on its own or employed as a ‘sculpted’ make-up gain for the compressed signal. The Low Mid Frequency (LMF) peaking band works in either of two discrete bell-width modes: Tight or Wide. Each mode has its own set of five fixed frequency detents - between them covering 40Hz-1.4kHz, plus a 10Hz Sub band - and up to 15dB of gain is on tap in Wide mode, while Tight mode’s more focused peak maxes out at +12dB. 

The Air Band is as awesome here as it is in Mäag’s EQ modules/plugins, giving up to 20dB of shelving boost cornered broadly at 10, 15, 20, 25, 30 or 40kHz. Adding sheen and presence to anything sent its way, the effect of the Air Band is felt way below the corner frequency thanks to the shape of the slope. It’s just fabulous, and you’ll want to use it on absolutely everything. 

At the very end of the signal path, up to 15dB of make-up gain is dialled in, and a soft limiter provides a final stage of compression. And down in the brainworx unit, the TMT (Tolerance Modelling Technology) section lets you select one of 20 slight variations in frequency response, time constants and other under-the-hood details for each channel, enabling analogue-style differentiation between multiple instances of the plugin in the same project. Then there’s a monoising filter for centralising everything below a selected frequency from 20Hz-22kHz, stereo widening from 0-400%, a pre- or post-compression low-pass filter (40- 220Hz), the dry/wet Mix control, and a bank of meters: Input, Output, Gain Reduction, stereo Balance and Correlation. 

Special K 

Right, let’s get the annoyances out of the way first: ratios, thresholds and gains are all displayed as values from 1-10, rather than x:1 or dB; the GUI is very small on a high-res display and can’t be scaled up; and Magnum Comp and EQ2 (as a whole, not its individual bands) could both do with bypass buttons. 

That said, the hardware Magnum-K is one of the tastiest pieces of studio gear of the last few years, and being able to call it up ‘in the box’ is endlessly exhilarating. Inserted on the master bus, it’s a bona fide miracle worker, effortlessly aerating, widening and coalescing mixes, and having a generally embiggening effect. But why wait til the mastering stage? The lift in gloss and power that it gives to vocals, guitars and other instrumentation is heavenly, too. Musical and magnificent, Magnum-K is a plugin that every serious engineer needs to check out. 

Computer Music

Computer Music magazine is the world’s best selling publication dedicated solely to making great music with your Mac or PC computer. Each issue it brings its lucky readers the best in cutting-edge tutorials, need-to-know, expert software reviews and even all the tools you actually need to make great music today, courtesy of our legendary CM Plugin Suite.