High-Resolution Linear-Phase Split Compressor for VST-Compatible Audio
LP SplitComp is a creative dynamic tool with unparalleled
transparency and sound purity combining the best of both the analog
and digital worlds.
The split function allows dynamic processing only in the band of
interest. Unlike many other split or multiband compressors the frequency
crossover is made with low-noise linear-phase filters. They allow
perfect band recombination after processing. The character of the
PlugIn can be continuously adjusted between being more compressor
or rather limiter. It provides a lot of psychoacoustically optimized
features like automatic dynamic characteristics, soft knee, and
parameterized soft clipper. To reduce the problem of alias frequencies
being often a hidden problem in digital non-linear processors, a
reference-quality oversampling has been implemented.
LP SplitComp is the second one in the new Algorithmix CHROMIUM
SERIES, a set of reference mastering PlugIns. The current release
is implemented as a stereo version, however it is intended to make
it VST 3.0 compatible as soon as the major audio editing systems
have switched to the new VST version. The compatibility to VST 3.0
will induce a multichannel version of the LP SplitComp.
Most fundamental but least understood
Dynamic processors, particularly compressors belong to the most
fundamental tools in every recording, mixing or mastering studio.
Despite the popularity and broadening of compressors they are probably
the least understood and most misused processors in daily routine
of the studio engineer. One reason might be that sonic changes of
a good compressor are very subtle and hardly perceptible for an
unexperienced listener. Another reason is the variety of parameters
which differ from one unit to the other and even for the same parameter
name exhibit a deviant behavior. The parameters are mostly interacting
in some way and need a lot of experiments and understanding to learn
how to use them in a purposeful manner.
A digitally implemented, well-designed mastering compressor has
not necessarily less parameters, but they are precisely defined
and de-coupled. In addition, due to novel, extraordinary possibilities
of the digital signal processing, supported by psychoacoustic findings,
digital compressors open a new quality window for mastering engineers.
Digital architecture with analog sound
The LP SplitComp arose from many years of experience of the
Algorithmix audio algorithm architects, countless experiments, and
critical sonic analysis of analog compressor legends. A serious,
often unrecognized problem of nonlinear digital processors is a
quite high amount of alias frequencies. They can ruin the best intentions
spent for a good functionality. Therefore the audio path in our
compressor has been equipped with a reference-quality oversampling
to reduce unwanted alias frequencies.
Parallel compressing is known already for many years. It is accomplished
by mixing the compressed signal with the direct signal in a mixing
console. In digital technology it is extremely important to provide
an exact delay alignment in the direct channel to avoid any unwanted
signal cancellation because of phase differences. Therefore we implemented
a properly time-aligned direct signal path. The Selective
mode the LP SplitComp provides a new unique derivative of
Of course, the LP SplitComp can cut a good figure as a
Full-Band compressor, but its true distinctiveness arises in
the Split-Band mode. The signal is divided in two complementary
parts: the first one is compressed and the second one is just passed
through without dynamic changes. Due to the high-resolution linear-phase
technology used for the implementation of the split filter, the
reconstruction of the compressed and complementary band is performed
completely without phase distortion contrary to some other split
or multiband compressors. The concept of the LP SplitComp
allow for very precise frequency-conscious dynamic processing. Especially
if you need to “repair” specific spectral parts in dense mixes you
will appreciate the surgical capabilities of this tool. Because
of a noise-free design you can use this compressor repeatedly on
the same material, each time concentrating on a particular dynamic
task or problem.
Looking into the future
Because of using look-ahead delay in the signal path, the overs
can be caught very precisely. Together with a respectively chosen
attack time, numerous methods of transient treatment are possible.
Using the Com/Lim feature you can make the processor more
acting as a limiter or compressor. You can even use two instances
of the LP SplitComp, the first one as a compressor and the
second one as a limiter.
The side chain of the compressor includes a range of filters to
make signal detection frequency dependent. The filters can be adjusted
identical to the split filter bank to perfectly master frequency-selective
tasks like de-essing or proximity effect removal. The static characteristic
allows adjusting different grades of knee rounding (soft-knee) in
order to make compression smoother, less obtrusive. A sophisticated
release computer provides program-dependent reaction to any complex
A lot of helpful features
At the end of the signal path a soft clipper takes care that the
output signal does not exceed the level adjusted in the Ceiling
field. In addition it allows introducing some controlled distortions.
To make the understanding and operation of the LP SplitComp
as easy as possible we have implemented some additional features.
The signal Monitoring is very comprehensive but yet intuitive.
You can click on different nodes in the block diagram and thus listen
to the relevant audio signals within the compressor architecture.
An additional feature, offered in a compressor only by Algorithmix,
is the Differ function. It allows listening to the difference
between input and output signal. So you can listen to the changes
you’ve done to the signal in the PlugIn. This difference is possible
solely because the whole path in the LP SplitComp is linear-phase.
You can also open a compact auxiliary Metering panel showing
all level meters and indicators simultaneously and place it to any
position of the screen.
You will love it
We believe, we have created a reference-quality compressor for mastering
engineers that opens new ways in efficient, transparent and surgical
dynamic processing. This compressor, however, is also intended as
a creative tool for any other kind of computer audio processing
in recording and mixing as well as in post-production, broadcast
and TV studios.