Mpressive!

by Hagen Fin
Amazona.de (Germany) – December 2007

The newest product from elysia is a completely analog compressor which is a true eye-catcher. But as nowadays the pro audio community praises digital compressors which have been trimmed to sound as accurate as possible, big screen computer monitors tend to obstruct the view on the analog world that certainly has not lost its importance.

elysia was founded by Dominik Klaßen, an experienced communications person, and Ruben Tilgner, who had been an important developer at SPL before, being responsible for the development for the well-known Transient Designer amongst others.

The mpressor is a very special compressor that can be used not only for ‚standard’ applications, but also for extreme sound design purposes. The sound of the mpressor is affected by the long lasting experience of the developer who has gained great expertise in level detection, VCAs and envelope technologies. But even more important is the competence to turn this knowledge into real-world products…

The housing somehow looks as if it was made of granite. Of course it is not made of stone, but of aluminum with a solid powder coating. The material thickness is amazing – at the most important places it's no less than 8 mm! The workmanship of the housing is terrific. Even the potentiometer knobs have been manufactured from solid metal; this is really something not to break easily. It might sound a little fussy here, but even the mpressor cannot keep up with the elysia alpha that actually utilizes bush bearings for its knobs.

In general the design of the mpressor can keep up with any award-winning plugin, but on the mpressor, everything is real and not just a virtual rendering. However, the optical and mechanical opulence is not used to plaster but to support the actual functions of the compressor. In order not to create any wrong impressions, we will listen to the unit later before coming up with any conclusions.

The technology of the mpressor is completely based on discrete designs, and I am not talking about those freely wired transistor balls, but a neat PCB layout without any IC opamps placed in a housing with an excellent mechanical build.

The complete circuitry emerged from specially chosen components, so that the idealistic sound philosophy could be put into practice in an optimal way. Taking a look at the mpressor’s guts makes it very clear that there has been no place for compromise. I have to admit that a unit like this – far from thinking pragmatically – really impresses me. If you are interested in reading more well-written information about the mpressor, I would suggest a visit of the elysia homepage as a bedtime reading by all means.

Well, I guess that our interested readers certainly know the basic structure of a compressor. What makes the mpressor especially interesting, to begin with, is the range of its parameters hardly to be found on any other compressor. While the threshold and the make up gain with its 16 dB of headroom appear to be quite normal, the fastest attack time of only 0.01 ms and a ratio controller going from 1:1.2 via 1:1 even into a negative area of up to 1:-4 are very striking.

Let us start with the attack controller. It features a switchable Auto Fast mode that activates a semi-automatic control of the attack parameter – something that reminds of the release function of some other compressors. Depending on the structure of the input signal, the mpressor will add a certain sound character to the audio material when the Auto Fast mode is engaged. Especially with attack times of less than 6 ms the result sounds very experimental pretty quickly. In many cases, only the clicking sounds of transient fragments remain, opening the door to playing and experimenting with your sounds in many ways.

Now we approach the release function which does not have the Auto Fast feature, but an Anti Log mode instead. This makes a release characteristic with an anti-logarithmic return line possible; resulting in extreme pumping effects that a standard compressor usually tries to avoid by all means. The manifested motto of the mpressor is: “Why just be normal?”

The range of ratio settings is also extended. After crossing the 1:1 point, you can even make 1:-X settings with the mpressor. But you should not mistake the effect for what an expander/gate does: While the expander features a negative ratio below the threshold, the mpressor employs its negative ratios above the threshold. As a true sound shaping device the mpressor works in hardknee mode.

But now let us proceed to the real delicacies. First of all, we find a function called Gain Reduction Limiter. The according controller determines the absolute amount of gain reduction the mpressor is allowed to make. Below this value, the audio signal will not be compressed any further, while it is possible to let the mpressor work extremely wild above this threshold by all means . Thus, nothing gets in the way of reshaping the transients on purpose.

Also out of the ordinary for a compressor is the equalizer section that is already exceptional in its own way: It works as both a high pass and a low pass filter around a selectable center frequency at the same time. If you turn the EQ Gain controller clockwise from its middle position, the frequencies above the center will be boosted while the lower frequencies will simultaneously be attenuated. The quality of the filter changes with the amount of gain, resulting in a high/low pass filter in the extreme positions of the controller. Sounds interesting? Well, this IS interesting!

The photos reveal that the mpressor has two complete channels which can of course be linked for stereo processing. It is a little pity that you cannot switch the EQ into the internal or the external sidechain path with the intention of providing even more possibilities at the push of a button. By the way: The mpressor pushes the second and third harmonics on high input levels in order to produce an extra fat sound. The manual can be downloaded from the elysia web site. It explains all functions very clearly and makes it easy to understand every aspect of the unit.

Dominik Klaßen from elysia on the mpressor:

AMAZONA.de:
Dominik, in times of high quality digital algorithms and – compared to hardware – affordable plugins, it is not necessarily obvious that good old analog technology can still be ahead in certain situations. Could you please explain this to our readers from your perspective?

elysia:
The main reason is that the processes which happen in analog circuitries are so complex that even today they cannot be copied by a hundred per cent. Let us stick to compression, because it is a very good example: The actual compression process goes hand in hand with a great number of non-linear effects, like the generation of additional harmonics. Hardware does this automatically in the highest imaginable resolution, but algorithms have to simulate these effects with an eye on the available CPU power. A simple resistor that you exchange for sound reasons can mess up the programming work of several days, because the effect of this easy swap will occur in many parts of your circuitry. Besides that, we still think that using hardware is much more intuitive than any software available – and then there is the problem that the technical progress of computer technology is so extremely fast that it keeps devaluating itself all the time. But we always point out that the quality of the converters has to match the niveau of the analog hardware; otherwise your analog equipment will not be able to evolve its full potential.

AMAZONA.de:
The mpressor has this exceptional equalizer – why didn’t you offer the possibility to insert this filter into the sidechain path?

elysia:
Here we have the typical problem of the all-in-one-device. When you come up with the concept for a new piece of gear, more or less every feature that could somehow be technically realized comes to your mind. But obviously nobody would want to use such a monster with thousands of knobs and switches. Having that in mind, you start to build the first test circuits with the features that you regard as the most reasonable, and then you let the actual practical benefit decide what is good and what gets the chop. In the beginning of a new project there is always the same tendency: you want too much. In the end, it is especially reducing things to the essential what makes a great product – otherwise you just cannot achieve the long-time effect of enjoying working with a unit. You must be able to perform your work quickly, and the results must be convincing at once. Especially with the mpressor, quite a lot of original ideas have been dropped in the development process. Anyway, we think that with its diverse special features, the mpressor has much more to offer than most other compressors without being impossible to use at all. Talking about frequency-selective compression in particular: this can be easily done by connecting any equalizer to the external sidechain input of the mpressor.

AMAZONA.de:
Please tell us something about your future plans. What can come after an alpha and an mpressor after all?

elysia:
As our basic concept and technology has been fully developed in the meantime, we have quite a lot of options to offer expedient audio hardware. Of course we will not close our minds towards digital technologies which keep getting better constantly, but in the end you have to do one thing after the other if you want to do it right. The most important question is: What do people really need? For us, the answer does not lie in copying units in every single detail that have been in the market for decades. We really do not think it is an analogy to make manufacturing modern audio hardware for contemporary demands on the basis of classic technologies our aim. Far from it! It is discrete circuit technology in particular which gives you the possibilities to directly put the ideas in your head into efficient real-world products. The list of potential ideas for the future is pretty long, but so far none of these ideas is concrete enough to make a product announcement. But one thing is definitively for sure: Whatever might come next, it will not have to hide behind the alpha or the mpressor by all means…

Conclusion
Words can hardly describe the enormous potentials of the mpressor, and in the short time we had it here we were certainly far from tapping its full potential. But we would like to invite you to listen to our sound samples in order to get a first idea. Looking at the mpressor from a straight technical angle, we would describe it as an analog high end compressor with excellent audio values. Its sound is an explicit antipode to clean digital compressors. With the mpressor, the correlations between amplitude modulation and THD virtually seem to jump into your face, with the bottom line that everything simply sounds much more alive than a digital emulation. We would not recommend the mpressor to pragmatists, though, as they can be sedated by a couple of freeware plugins most of the time :-) What accounts for the true flexibility of the mpressor is the fact that it certainly cuts a brilliant figure even when it is used as a ‘simple’ standard analog compressor. Extraordinary! A must-have item…

PLUS
+++++ Great analog sound
+++++ Workmanship
++++ Flexibility

MINUS
- EQ cannot be switched into the sidechain path