elysia mpressor plugin

by Martin Keller
Keys (Germany) – February 2010

More or less true-to-original emulations of luxury audio hardware have become quite common in the plug-in market by now. The recent trend is that boutique manufacturers appear in this segment more often than ever before. These companies are known for setting a high value on the software living up to the standards the hardware has set before.

The high end company elysia (located near Düsseldorf) is still a quite young business that has been launched by Ruben Tilgner and Dominik Klaßen in 2005. The central philosophy of the elysians is innovation. They like to leave well-used paths in favor of advanced technologies. Having this in mind, it is not really a big surprise that the mpressor offers feature not to be found on other compressors very often...

The emulation has been programmed by the Brainworx team which is known for their professional plug-ins bx dyn EQ and bx digital, raising hope that the mpressor emulation should convince with superior audio qualities, too.

The physical model of the plug-in costs nearly 5000 USD. It is designed of discrete analog technology and offers lots of technical finesse like an integrated temperature stabilisation system. With its transistor circuitry the mpressor is among the fastest compressors available, with (not only) very fast attack and release times.

The plug-in requires an iLok, its installation runs without problems: install the demo, load the authorization to your iLok, ready. A first glance at the GUI shows that the plug-in has all the functions of the hardware. It is available in the following formats: RTAS, VST, AU and TDM.

Overview on the functions of the mpressor
The link button decides if the channels should be compressed as a stereo mix (more mid focused sound with more punch) or independently from each other (more vivid sound).

The threshold controller goes from -18 to +16 dB. Practice shows that this range is absolutely large enough. Still I kept wondering why the mpressor only starts at -18 dB, while some other compressors have -60 dB as their lowest value. The answer is that the hardware has a dedicated trimmer for adjusting the threshold internally. The software does not have this feature, but here the threshold has been adapted to DAW use by the developers.  

Next to the threshold we find the sidechain button. If the host software supports this feature, the mpressor can be controlled by an external signal (an additional audio channel which is routed into the sidechain input of the mpressor). The VST plugin directory shows a standard and a sidechain variant. On top of this, the 'Dynamics' directory also offers a VST3 variant of the mpressor.

The attack time starts at 0.01 milliseconds and ends at 150 milliseconds. At the fastest value only the very first transient get through – not much more than a click. If the mpressor is used on group channels with a longer attack time, an additional semi-automation called Auto Fast keeps track of the input signal: If a signal with a short, very loud attack appears, the mpressor will react with reducing the attack time only for this critical passage. Complex automations for dynamically demanding source material are no longer necessary.

The release parameters covers a broad range from super fast 5 milliseconds to 1.2 seconds. The Anti Log feature which has its button directly next to the release controller creates unusual compression effects. While the usual logarithmic release circuitry shortens the release time at falling levels in order to work slower on lower levels, the Anti Log mode just turns this on its head: Long release times for signal peaks make for some audible compression effects which are useful for creating backwards sounds, for example. Especially when used on drums this produces an obvious rise in sustain, which pushes the ambience into the foreground.

As a specialty of the mpressor, negative ratios can be set to achieve dramatically pumping compression effects. The ratio scale goes from 1.2 to 10 and from -0.3 to -4. While a positive ratio reduces the signal above the threshold only (divided by 2, 3, 4 … or exactly held at the threshold itself when used as a limiter), negative ratios reduce the output in correlation to the input: the louder the input signal is, the stronger the reduction becomes. Dynamics turned upside down! This renders unusual effects and even sonic destruction possible. The Gain Reduction Limier is a great help in smoothing out warpings which would just be too much. This limiter is not situated in front of the compressor or after it, but it is placed directly in the compressor circuit where it controls the maximum allowed amount of gain reduction. One of the benefit is that it becomes possible to not compress loud passages any further than the set value, which means that the rest of the dynamics of a signal remains intact.

The EQ is not a me-too solution either: the so called Niveau Filter can be imagined as a balance in the frequency spectrum. A clockwise turn of its controller cuts the bass and boosts the treble at the same time, and it behaves just the other way round in the counter-clockwise direction. The center frequency can be shifted from 26 Hz to 2.2 kHz and by pushing the 'x10' button from 260 kHz to 22 kHz.

Finally there is the output gain controller and an LED chain which shows the processing intensity of the compressor and the activity of the Gain Reduction Limiter. The layout of the interface is clearly arranged and logical, one does not have to consult the manual to get started. The labeling of the controllers is just too space-saving, though. If you don't have magnifying glasses as a part of your equipment, maybe you should think about investing in them.

The sound
Although it is not an emulation of a tube compressor, the mpressor delivers a decent and warm sound which is clean and of high resolution. The EQ can spice up the sound or reduce harsh treble frequencies. The mpressor operates at an internal sample rate of around 192 kHz, even if the host operates several steps below. For example, if the project resolution is at 44.1 kHz, the mpressor will work at 176.4 kHz, at 48 kHz and 96 kHz the mpressor will work at 192 kHz. Despite this oversampling technique the system load remains moderate. 

The layout is logical and user friendly. A quick start is possible even without the manual. Because of the extremely fast attack and release times, the integrated limiter and last but not least the EQ, it's hard to think of an application that the mpressor could not cope with – not to mention its potentials as a sound shaper.

Result
elysia has made a great debut into the world of software with the mpressor plug-in. The mpressor can be used on versatile occasions: processing single signals and subgroups, mastering and sidechain applications. The sound is excellent, clear and warm with a high resolution. The special features like Anti Log and negative ratios described above allow deep transformations and manipulations which point out the mpressor's qualities as a unique tool. This is not just another copy, but the completely convincing emulation of the boutique original. Because of the quality and the range of possibilities the price is fair.