Kush Audio UBK-1 review

  • $199
The UBK-1 brings warmth and colour to the mix.

MusicRadar Verdict

Sonically stunning, UBK-1 excels at bringing authentic, flavoursome analogue character to drums, acoustic instruments and mixes.


  • +

    Broad sonic colour spectrum; easy and intuitive to use; creative compression; warm analogue character.


  • -

    No attack/release controls; misses a bit of aggressive bite and spit; currently RTAS-only for Windows.

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.

Kush Audio's UBK-1 generated quite a buzz among those in the know prior to its recent launch.

Kush is known primarily for its modified version of Empirical Labs' Fatso compressor/saturator, known as the UBK Fatso. It's a fabulous boutique 'betteriser' box that's found its way into the studios of numerous high-calibre producers. The announcement that Kush had been working on a plug-in (albeit not a software version of the UBK Fatso), then, was big news.


The UBK-1 is a three-stage processor comprising separate sections for Saturation, Compression and the more nebulous Density, with each designed to push the incoming audio into an analogue frame. It comes in AU (Mac) and RTAS (Windows/Mac) flavours, with VST and AAX said to be on the way.

"The UBK-1 works equally well as an insert on individual tracks - such as vocals or acoustic instruments - and as a buss processor on drum groups or an entire stereo mix."

Gregory Scott, the man behind Kush, describes the UBK-1 as a "motion-generating character compressor," and to understand what he means, you really have to get under the skin of this intriguing virtual device.

UBK-1's three stages are independent of each other and placed in a fixed series. Each can be bypassed by clicking its VU meter, and the gain structure is such that big volume jumps are automatically counteracted, which really helps when assessing the effect on a signal.

The first processor is Saturation. It generates pleasant harmonic distortion, softens transients without losing too much attack, and includes a wet/dry mix control for parallel processing. It's not modelled on any particular tape or transformer character, and, with just one control knob, is designed to be tuned by ear alone.

The mix of saturated and unsaturated signal is then passed on to the Compression section, which also boasts a wet/dry control, enabling you to tweak the depth of compression and let abit of transient through if you so desire.

A choice of five compressor models is on offer; each has its own particular response character (a combination of attack, release, ratio and knee) and a descriptive name (Splat, Smooth, etc).

Pick one, set the dial somewhere between Mild and Intense, and adjust the wet/dry mix - compression doesn't ever get much easier than this. There's also a welcome high-pass filter on the sidechain, to reduce the effect of low frequencies on the compression - great for drum busses.

Finally, the mix of compressed and uncompressed signal (which, remember, is processed from the previous mix of saturated and unsaturated audio) moves on to the Density stage. This processor adds definite but very subtle substance to the top or mid-range of the sound. Essentially a combination of frequency-selective compression and saturation, the effect is heavily dependent on the results of the previous sections.

The amount of drive into all three stages is controlled by the Headroom knob. Lower it for more drive (ie, less headroom) or raise it for more subtle results (more headroom). Green and red virtual LEDs represent whether you have ample or no headroom respectively.

The developer's advice is to initially set this so that green is lit up about 50% of the time before you touch anything else. Once you've got the rest of the controls set, you can overdrive it into madness, if you want.

Buss power

Now we know the theory, what happens in practice? Well, the UBK-1 works equally well as an insert on individual tracks - such as vocals or acoustic instruments - and as a buss processor on drum groups or an entire stereo mix.

Its most obvious application is on a drums buss: parallel processing can be applied, which is where that "motion-generating character compressor" description comes in. By subtly altering the compression settings, you can take abroad level of control over the way the drums drive or groove.

For dance music, it's a mixed bag of results. The slower genres - hip-hop and dubstep, for example - benefit from the languorously rude compression characteristics, while the faster styles - house, techno, DnB - are unlikely to find the toughness they're after.

Over the whole mix, you can think of the UBK-1 in visual terms as a filter - a sepia tone, for example - that brings character and colour. Avery subtle amount of the saturation changes the mood and feel by impression and gives your tune a more unified sound.

The character of this effect is undeniably great, but without control of the compressor stage's attack and release, you're stuck with the prescribed settings, which for some won't be entirely satisfying. You might not get the bite or toughness needed for a heavy rock mix; though for a softer, more open acoustic or jazz mix, it's ideal.

A few hidden controls wouldn't do any harm - we're thinking of those on PSP's VintageWarmer, where you can 'go round the back' for more precise response time control. That said, what Kush has created here is a very musical analogue-modelling plug-in that perfectly suits more open styles of production, doing a superb job of bringing performance nuances and detailing to the fore.

Drum abuse clinic

A vitally important thing to understand about the UBK-1 is that there are no right and wrong settings: it can be subtle and it can be rude, and it welcomes abuse. The range of different actions you can produce through combinations of the various compression types, the high-pass filter, the parallel wet/dry balance and the compression intensity have a profound impact on the articulation of a drum groove.

The results are exciting, impressive and very usable in mix conditions, bringing the kit forward, upping the energy and exposing the subtleties of the performance. The spread of toms and kick drum can be amazing, and the detail of the room (and control over its level) is a joy to behold.

One effective technique is to select an extreme compressor setting - so that it's sucking and blowing like crazy - and then raise the high-pass filter to keep the weight of the kick drum, before winding it back with a low wet/dry balance. This will provide a hint of madness behind the impact of the uncompressed drums.

The Density parameter, though subtle, is like the difference between good and bad gravy. Adding density to the kit bus (especially at the top end)adds a level of substance that helps the readability within a mix.

Its weight in gold

So, is this boutique processor worth the asking price? Absolutely.

The UBK-1 has clearly been designed by someone who possesses a very musical ear, resulting in a device that brings the sort of colour you'd naturally get in the analogue domain to a mix. Generally, it's very warm and very fat, and it particularly excels when deployed for heavy drum mishandling or, alternatively, used lightly on spacious productions.

It takes a while to tune your ear into everything that UBK-1 can do, but gradually you get a feel for its sonic characteristics. After that, using it is much like playing a musical instrument as you work to shape the sound.

It's an 'engineer's secret weapon' if ever there was one.

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.