The elysia mpressor is a new tool for
creative dynamics processing. On top of the tried and tested standard
features, this creative compressor provides several special functions
that produce fat and freaky sounds by employing a punchy control
behavior, colorations full of character and extreme settings. Besides
classic tracking applications, its favorite domains are groovy effect
compression and creative sound design.
Each of both linkable channels offers a switchable Auto Fast
function that allows very fast yet distortion-free compression without
any artifacts. The Anti Log circuit generates explicit compression
effects such as pumping and breathing. As the mpressor is a true feed
forward design, it also allows negative ratios which result in the most
ex-treme over-compression effects. The Niveau Filters can change the
character of a track from subtle to striking with the possibility of a
continuous frequency shift. The Gain Reduction Limiter is a novel
feature that lets the user choose the maximum amount of Gain Reduction
he wants to draw from the unit, and this at the twist of a knob. The
switchable external sidechain inputs make for further flexibility in
terms of compression behavior.
The circuit design of the mpressor is completely based on discrete
analog technology. The entire signal processing is implemented with
single transistors in permanent class-A mode, and even the sidechain
and power supply are composed of fully discrete circuits. An oversized
power transformer, capsuled conductive plastic potentiometers, internal
temper-ature stabilizers for critical components as well as special
current feedback amplifiers are part of the technical finesse. The
combination of these elements aims at the maximum reachable signal
quality and guarantees clean and powerful sound characteristics even
when extreme settings are used.
The creative compressor
Compressors are absolute standard tools in daily studio work, but
depending on the specific task they need to be used in lots of
different ways. The range goes from mild changes of level during
mastering to limiting the dynamic range in recordings to extreme
compression to shape sounds envelopes.
Hence the various topologies and large range of compressors in the
market today. The mpressor is a typical recording and mixing compressor
that can handle a wide array of jobs because of its premium audio
quality and precise control characteristics. On top of that, it offers
a number of special functions that enable the user to create completely
new and very spacy sounds.
This makes the mpressor a truly creative compressor that
especially convinces with its elaborate and practical innovations.
Reducing options to the essential makes it possible to achieve
outstanding results for any audio material at first go.
The control characteristics of the mpressor offer a great spectrum of
settings without generating any unwanted artifacts or noises. Even very
fast attack and release settings can be used without any problems.
Already known from the alpha compressor, the Auto Fast feature is a
guarantee for very fast but undistorted gain reduction processes: If
this function is activated, the attack time will automatically become
shorter on input signals with fastly rising levels and intense changes
The novel Anti Log function generates an anti-logarithmic
progress of the release curve. The release time will at first become
slower when there is an ample increase of compression. As soon as the
input signal returns to a noticeably lower amount, the release time
will be shortened automatically. Depending on the other settings,
compression will become much more audible than before as a result. This
feature can be used to achieve BPM-dependent dynamic effects,
manipulate the ambience parts of a reverb effect return, or process
single sources such as vocals or bass.
Gain Reduction Limiter
Another specialty of the mpressor is its limiter for the control
voltage. With it, one can set the maximum amount of gain reduction that
will not be exceeded as long as the function is active. Normally the
threshold and ratio parameters determine the amount of gain reduction
which is adapted to the input signal in order to reduce the loudest
parts as desired.
If the limiter is set to a maximum reduction value, threshold and ratio
can have completely different settings without changing the maximum
gain reduction. In this manner, very special variations of control
characteristics can be achieved, e.g. applying a strong amount of
compression while preserving the dynamics of loud passages at the same
Combining the Gain Reduction Limiter with the external
sidechain transforms the mpressor into a true ducker. In this
application, the music will automatically be turned down when a voice
sets in (or just the other way round). Another option is to apply
upward compression that only raises the volume of the quieter parts
without changing the actual dynamics at all.
The mpressor provides a switchable external sidechain input per
channel. Once it is activated, the compressor reacts to the fed in
signals and opens up an enormous variety of additional potentials. A
typical application is frequency-dependent compression, where an
additional equalizer is used to give certain frequencies a stronger or
weaker influence on the overall compression.
True ducking effects are also possible as well as very cool
groovy sounds, e.g. controlling a stable synth pad with a drum beat fed
into the sidechain. The combination of the Anti Log and Gain Reduction
Limiter functions result in very unusual effects that sound like an
inverted gate: the loud signals are reduced intensely while the quieter
parts come in front more obviously.
In order to add flexible sonic stamps to compressed signal, there is a
Niveau Filter placed after the compressor section which has been
designed in the style of the audio EQ of the alpha compressor.
It also boosts the high frequencies beyond a selectable center
frequency and cuts the low frequencies at the same time (or, depending
on the individual setting, just the other way round). But according to
the intended use of the mpressor, we have made the possible settings
more extreme for more striking and dramatic effects. Only two
controllers produce a great variety of different sounds.
These kinds of settings could not be generated by using
standard parametric equalizers. The combination of this filter and the
special control characteristics enable the mpressor to give a totally
new character to the original signal which can vitally enhance a whole
Here is an old elysia saying: If you want to make it right, make it
discrete! Of course this is also true of the mpressor, as the
combination of very extreme control characteristics and an absolutely
convincing quality of sound can only be achieved by using discrete
circuitry. Therefore all signal stages were designed to use single
transistors, resistors and capacitors, so each of the stages could be
perfectly matched to its specific task as an important side effect.
Many parts of the circuitry do without negative feedback, and
the complete unit works in constant class-A mode in order to ensure the
best audio quality in any situation. Even the sidechain and the power
supply are built with the exclusive use of single transistors,
resulting in considerably lower noise compared to conventional ICs.
A look inside
The choice of components for the mpressor did not leave the slightest
room for compromise � a great part of components which are used in the
alpha compressor can also be found in the mpressor. All controllers use
high-grade conductive plastic potentiometers. All switching functions
are coupled via capsuled relays which are placed at the ideal places in
the circuitry in order to keep the signal path reduced to the max.
A special input stage was trimmed to show a similar behavior to that of
an input transformer. Furthermore, this stage distinguishes itself by a
very good common mode rejection and an extra low capacity, preventing
unwanted changes of the input signal effectively. A high-grade class-A
output stage delivers adequate current to drive even long cable lines
The power supply also benefits from the discrete design, as the voltage
regulators produce such a low amount of noise that it can hardly be
measured at all. A generously dimensioned toroidal power transformer
provides enough current to charge the great number of quality
electrolytic capacitors very quickly.
Certain critical components of the discrete circuitry are
surrounded by special heating elements made of copper. This keeps
important parameters constant and makes them independent from changes
in temperature and operating time.