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Sonimus TuCo

Compressor Plug-in By Dennis J Wilkins
Published October 2017

The latest vintage-styled plug-in from Sonimus is a neat compressor with a vari-mu flavour.

Plug-in developers Sonimus are already well known for excellent emulations of analogue EQs and consoles, but although their first compressor is based on a variable-mu tube circuit as used in the Fairchild 660 and 670, it’s not an emulation of those venerable units. Rather, TuCo shares some of their ‘analogue’ sonic characteristics and adds a few useful features. It’s available on Windows and Mac OS, in AAX, AU, VST 2.4 and VST 3 versions.

Sonimus TuCo compressor plug-in.TuCo has a clean-looking front panel, with Amount, Output level, Release time and Drive controls, plus a Mode switch. Drive adjusts the ‘tube’ saturation level of the output stage, while Mode engages combinations of attack times and compression ratios. Modes 1 and 2 are compressor modes with slow and fast attacks, respectively. Modes 3 and 4 are limiter modes, again with slow and fast attack times. My testing found that the ratio values in the compressor modes vary from about 1.5:1 to 4:1, while in the limiter modes, ratios run from about 4:1 to 8:1. The actual ratios vary with the Amount setting and signal levels.

Attack times are affected by the incoming signal level, and by Mode, Amount and Release settings. Modes 1 and 3 offer attack times from approximately 15ms up to 200ms, while modes 2 and 4 yield attack times from under 5ms to about 50ms. Attack times vary significantly with the Release setting, roughly doubling when Release is increased from 0 to 10. Release times in all modes run from about 50ms up to approximately 1 to 1.5 seconds as the Release setting is varied from 0 to 10. As you can probably tell, this is a ‘set by ear’ compressor, not one offering mathematical precision!

The Drive control runs from essentially inaudible distortion up to very crunchy. I liked what it added to some drum and bass sounds, helping them cut through a mix. Other useful features include a side-chain high-pass filter (10 to 350 Hz) to reduce ‘pumping’ caused by low-frequency instruments such as kick drums, and an A/B switch to allow the user to compare two sets of settings. In addition, there is a new feature for Sonimus: a handy built-in preset system. Of course, when used in a DAW project, TuCo will remember all its settings as any well-behaved plug-in should!

Both Sides Now

A more unusual feature is the ability to change the way the side-chain detector and signal processing respond to stereo input signals. The Mono setting combines the left and right input channels, generating a mono output, while the Dual Mono setting makes the actions of the left and right channels independent, which is useful for techniques such as ‘rear bus’ parallel compression. Vintage mode sums both channels for signal detection, and applies the same gain reduction to both channels. If one channel has a level change, up or down, the same gain reduction will be applied to both channels. In Modern mode, by contrast, each channel is processed separately, but a ‘diode’ scheme ensures the louder channel dominates gain reduction.

Testing these two detection schemes on a range of sounds, I found the difference was subtle, but with some drum mixes, the vintage mode seemed to add something appealing. However, as we should always be aware, louder sounds better, and even though I had used exactly the same settings in the vintage and modern modes, Nugen’s MasterCheck showed the output as being between 0.5 and 2 dB louder in vintage mode, while PLR (peak to loudness ratio) was typically higher in the modern mode. While Sonimus indicate the modern scheme is more applicable to mastering, I found both to be useful on full mixes depending on the musical style. Definitely let your ears make the decision!

A week after the initial release, Sonimus released a minor update adding Automatic Makeup Gain and a Mix control option that enables the dry signal to be added before or after the output gain control. I found AMG to be an incredibly useful (and not really minor!) addition. Without AMG enabled, the output level drops 25 to 30 dB as the Amount is increased from minimum to maximum. This can be compensated for manually using the Output control, which provides up to 40dB of boost, but AMG does the job automatically, and in my tests, matched the gain to within ±1dB over the full Amount range with a variety of signals. A very welcome addition!

Tu Good To Be True?

Whether I ‘shaved off’ just a few dB from peak levels or crunched a signal severely, TuCo always delivered musical results. Vocals and instrument sounds could be transparently controlled with gentle settings, or ‘pumped’ using the limiter modes and higher settings. I found no other compressor emulation in my studio that handled a full mix as well. And TuCo also seems to help ‘glue’ a mix better than most plug-ins I have heard.

TuCo is not the only compressor you’ll ever need — it has no external side-chain input, and only one set of controls, so that in dual-mono mode both channels have the same settings — but for compressing tracks or mixes, it’s a fine evolution of a classic tube compressor, and excels in its sound and performance.


  • Simple controls that yield excellent compression results and a sonically pleasing ‘tube’ sound.
  • Reasonably priced.


  • No external side-chain input.


TuCo is a fine-sounding and effective compressor, with some useful additional features.