Elysia mpressor software plugin

by 96kHz.de & Klangfabrique
96kHz.de (Germany) – December 2009

Just about two years ago, elysia caused a sensation with their analog 'creative' compressor. Now they are aiming at transporting this success into the virtual studio world... the mpressor plugin is presented as the true-to-original emulation of its hardware counterpart.

Companies like Neumann and Brauner have proved that German engineering art set international standards and can be looked upon as a 'seal of quality'. elysia still belongs to the younger generation of companies, but in spite of a rather small product portfolio they have been able to convince a large number of professionals with their high audio quality and innovative concepts. By cooperating with Brainworx for the software emulation of their mpressor, elysia could count on the expertise of another young and successful company. The software specialists took care to not only recreate the complex compression processes of the original, but also its signature sound (including the generic noise floor). During this test we will figure out if the mpressor can enthuse us as a universal dynamics tool, mastering compressor and creative effects processor also in its software version.

Hosts – formats – installation – copy protection:
At the moment, the mpressor plugin is only available in the native Formats (TDM coming in December 2009), but you should be able to integrate it into any virtual studio surrounding. There is a version both for Windows and Mac, and you have the most important formats VST (2 and 3!), RTAS and AU. The download version can be directly attained from the elysia website, and its installation is fast and easy. You have to use an iLok as copy protection, though.

Engine:
If lower project sample rates are used, the engine of the plugin will use a higher resolution than the host in order to live up to the high quality standards of the original. For example, in a Nuendo session at 48 kHz the signals will be processed at 192 kHz by the use of 4x oversampling. At sample rates between 50 kHz and 100 kHz the mpressor still uses 2x oversampling. Because of these high sample rates, the plugin can react faster to changes in the source signal, and there are also more reading points that generate a more precise virtual control voltage, resulting in a more accurate compression process.

Design and handling:
'True emulation', this is what the manufacturer calls the process which is responsible for recreating the compression and sound characteristics as close to the hardware as possible. Even the graphical user interface follows this directive; it looks like an almost photo-realistic representation of the original. The plugin shows only one single control panel, whereas the hardware has two of them and can therefore be used as a dual mono compressor with completely independent settings. This should not be a disadvantage for software users, though, as unlike a hardware a plugin can be opened in multiple instances and used as many times as needed. A small drawback of the nice design is the relatively small lettering that sometimes calls for reading glasses. All controllers can be operated with the mouse, a hardware controller or even with the mouse wheel without having to click the controller first (there is also a fine tune mode). 

Functions explained:
The plugin offers the complete functionality of the hardware model. The Link button lets the user chose between stereo and dual mono mode. If the Link button is active, the virtual control voltage will be generated from a mix of the left and right input signals, which will be the standard setting for most stereo and sum applications. If the compressor runs unlinked, left and right channel will have their own virtual control voltage generated from their specific input signals (but with the same controller settings).

The Threshold controller of the compressor offers a range between -18 dB and +18 dB.

Next we find the Sidechain button that makes it possible to control the compression process by an additional external audio signal. Of course, the host software must support this functionality. In ProTools 8 and Cubase 5.1 this proved to be very easy. Owners of older VST hosts can use the common workaround of assigning a quadro bus, as the mpressor pops up in the routing window of Cubase/Nuendo (just drop us an email if you want to learn how this works: redaktion@96khz.de).

As mentioned earlier while talking about the oversampling technique, the mpressor has very fast control characteristics and offers attack times between 0.01 and 150 ms. The attack parameter is extended by the Auto Fast function, a special circuitry originally developed for elysia's alpha compressor. This semi automation helps to catch unsuspected fast impulses even when a longer attack time has been set. It recognizes fast and loud transients and automatically shortens the attack parameter for a moment and then returns to the original value set by the user. This way the compressor is only fast when you really need it. We found this very useful especially when compressing complex sum material, where a fixed short attack time would help to catch the impulses, but only at the risk of audible distortion in the sustain phase of the signal.

The release time can be set between 5 ms and 1.2 seconds. With the so called Anti Log function you have a very nice added specialty that clearly belongs into the creative categorie. This button switches the release curve from a linear mode to an antilogarithmic progress. Most compressors usually work with linear or logarithmic release characteristics to achieve subtle and gentle compression results. With Anti Log, however, the release time remains longer at the beginning once the threshold has been passed to become strongly accelerated when the input level starts to fall. This process works independently from the total amount of gain reduction and is therefore available even for lighter compression. In terms of sound, this effect can be described as a mixture of reverse sounds and compressor pumping action.

The extended functionality of the ratio parameter is perhaps not so easy to comprehend at first sight. This controller does not only provide continuous settings from 1:1 to 1:10, but also a range of negative values which goes up to 1:-4. If a negative ratio is employed, the characteristic curve will bend and go back down again. This means: the louder the input signal, the stronger its reduction. Depending on the source material as well as the chosen attack and release settings, the results go from pumping to reverse-reverb-like effects.

The Gain Reduction Limiter is another specialty of the plugin and should not be misunderstood as the well-known peak limiter. It does not limit the audio signal, but the control signal of the compressor instead. The result is that signals will not be compressed any further once a fixed value which has been set with the controller is reached – loud passages exceeding this value can retain their original dynamics!

Let's get more specific for a better understanding: the threshold of the mpressor is at 0 dB and the ratio at 1:2. The signal passes the threshold and is reduced at a ratio of 1:2. This means 2 dB at the input will be reduced by 1 dB at the output, 4 dB reduced by 2 dB, 10 dB by 5 dB and so on. Now the Gain Reduction Limiter is activated at + 4dB. This time the compressor treats every signal passing 4 dB mark as if it was exactly 4 dB only, so even the 10 dB signal would only be reduced by 2 dB.

Finally, the mpressor also offers a sound shaping facility with its Niveau Filter. This is a little bit different than the usual equalizers, as it is a combination of a high shelf and a low shelf filter which always work contrary to each other. The EQ Freq controller sets the center frequency (between 26 Hz and 22 kHz). If the frequency range above this center is boosted, the frequencies below will be cut at the same time. You can easily imagine this by imagining a pair of scales. Alternatively, this filter can be used as a high or low cut in the extreme positions of the EQ Freq controller.

Ergonomics:
It is easy to start working with the mpressor because of the logical layout of its control panel, especially if one sticks to the standard and known parameters at the beginning: you get what you would expect from a high grade compressor without any troubles. But also the special functions can be used effectively after only a short introduction phase (something which is not always the case with every competitor). Of course it is always a good idea to have a look into the very well done manual. Instead of just including some presets in the plugin menu, the manual describes how and why they work in detail. On top of this there are a lot of audio samples available at the elysia website. 

Sound:
The first listening impressions already reveal the accuracy of the software developers: not only did they transfer the elaborate functionality of the hardware into the virtual world, but they also nailed its sound character. The mpressor plugin satisfies with a very transparent sound and a convincing, analog-like and unobtrusive warmth. Even subtle processing shows this classy character, reminding  of expensive analog mastering equipment.

The possibilities in terms of dynamics processing are really very broad. The mpressor easily masters any task from slightly compacting signals to emphasizing transients – everything you would expect from a modern compressor. It also does a remarkable job as a sum compressor. Drums groups can be compressed effortless without the danger of unexpected signal peaks causing the compressor to pump by engaging the Gain Reduction Limiter.

As if this would not be enough in its own place, the special features of the mpressor invite to perform sound experiments that are somehow difficult to explain in writing. Usually it would take long chains of effects and parallel compression to come anywhere near this. It is really worth listening to the mentioned demo sounds and giving the 14 days demo version a try to find it out for yourself.

Value for money and competitors:
The mpressor is in the higher price category of software dynamics plugins. On the other hand, it gives you quite some long-term benefits. Adding it to your arsenal of plugins could make lots of other dynamics plugins obsolete. It would be great if there were bundle prices in case elysia decide to emulate their mastering EQ in the future, too.

Conclusion:
The competition among the plugin companies is very hard, therefore a newcomer will naturally have a hard time finding a space between the well-tried top dogs. Especially when it comes to dynamics processing, there are a lot of great emulations of successful analog processors as well virtual-only variants with trendsetting functions. However, the mpressor by elysia has all the potential to stand out of its competitors. On the one hand, it shines because of its sonic qualities, its accurate and solid dynamics processing, its flexibility and its intuitive operation. On the other, its functionality outranges normal compressors by offering new and and almost playful ways to create unimagined soundscapes. The title 'creative compressor' is justified by all means. 

The mpressor does a fantastic job at processing all different kinds of different single sources as well as sum signals. Its very good sound is as convincing as its new concepts like the Gain Reduction Limiter, even when it is used as a mastering compressor. Only its fairly high demand on processor power could prevent users to insert the mpressor on every single track of their mixes...