RECORDING November 2024 - 42

-Review by Bill Stunt
Black Rooster Audio
OmniTec-436C & VTC-2
A pair of Mojo-infused vintagestyle
compression plugins
Founded in Germany in 2016, the 23-strong Black Rooster
Audio plugin roster includes eight dynamics processors made
up of vintage emulations and in-house-designed compressor
offerings. The two latest additions come from each category.
The OmniTec-436C is a take on the famed Altec 436C
variable-mu compressor, while the VTC-2 is a Black Rooster
original inspired by vintage tube-based compressor designs.
From the 1950s to You
Released in the 1950s, the Altec 436 tube compressor has a
storied history. Initially designed for use in PA systems of the day,
it quickly found its way into the recording studio. It was widely
employed to tame dynamics on recordings by artists like Frank
Sinatra, Herb Alpert and others. The heavily EMI-modified Altec
436C was arguably central to the sound of the Beatles.
Tubes and Variable-Mu
The 436C is a variable-mu (often shortened to vari-mu) type
circuit where the current sent to the tube's grid decreases when
more gain is fed to the input, resulting in attenuation of the output
signal. The ratio is input level dependent, rising as you drive the
circuit. It's a simple but effective design.
OmniTec-436C
The original hardware 436C featured a minimal control set
consisting of an input level knob and two set screws for adjusting
release time and threshold. The plugin expands this into a more
robust toolset that includes toggles for setting Mode (limit/compress)
and Link (dual mono or stereo signal processing). There are
Hi and Lo side-chain pass filters with a " listen " function for delta
monitoring. You also get controls for Attack, Makeup Gain and
Mix. The plugin's aesthetic nods to the original with its distinctive
" Altec " green color scheme, distressed face plate and central, circular
gain reduction VU Meter.
A Mojo Filter
Black Rooster set out to capture the warmth and analog goodness
of the hardware by accurately emulating the circuit and
characteristics of the vari-mu style compression. They've done
that effectively. Just running a signal through the plugin with no
compression ever so slightly flatters the sound with a subtle but
effective warmth and girth.
42 RECORDING November 2024
Smooth, firm, natural-sounding compression kicks in as you push up
the (input) gain knob. You can nuance the blend of tube saturation by
playing off the input gain and the threshold setting. Significant, pillowy
attenuation is available if you want or need it, but I found the plugin
sounded best in the 2 to 5 dB attenuation range. Using multiple serially
inserted instances worked well when I wanted more control.
I tried it on drums, bass and vocals, and it was effective on all
three. The blend of natural attenuation and warm saturation especially
complements bass beautifully-even more so when using multiple
instances. It's also a natural on vocals, where it adds a nice special
" something " to a ballad vocal. The attack and release range isn't
stated, but the quickest settings are adequate for busy tracks. Finally,
it's darn effective on drums, where you can get a range of results from
subtle control to vibey " aggro " depending on the settings.
On a stereo bus, modest compression in dual mono mode can
give a real vintage vibe. The slight push and pull between the sides
results in a perceived wider sound field with added warmth. I'm
certain I could dial in a setting that would work on any source that
would benefit from added vintage-flavored warmth and effective
level management with this plugin. One last thing to note is
that while the Black Rooster OmniTec-436C is clearly " modified "
thanks to the expanded feature set, there is no indication that it
seeks to ape or be an emulation of the classic " EMI/Beatles " units.
I like that it retains a touch more of its Altec heritage as a result.
Black Rooster VTC-2
The Black Rooster VTC-2 (VTC stands for vintage tube compressor)
is also modeled after popular tube leveling amplifier circuits
from the '50s, '60s and '70s. Though not stated in the manual,
to my ears, the VTC-2 functions and sounds more like an Opto
compressor than a vari-mu type.
Visually, it does exhibit a certain blue " Tube Tech-ish " appearance,
and its expanded feature set is certainly more aligned with
that of a Tube Tech CL-1B, which was itself a " take " on earlier
classic Opto designs.
Controls
The interface features an on/off bypass switch and a Link mode toggle
(dual mono/stereo, just like the OmniTec-436C). There are four
ratio choices: 1:2, 1:40, 1:10 and 1:20 and continuously variable
attack and release controls. Modern plugin additions include Drive
and Threshold controls plus dry/wet Mix and output Trim controls. The
meter display simultaneously employs a pair of needles, with the righthand
one indicating the input level and the left gain change.
Good Vibes
The tube emulation is apparent immediately. The virtual circuit
can be driven from subtle to " vibey " second-order harmonic distortion.
Just like a good hardware compressor, you could effectively
use it for that purpose alone.
The compression can be equally subtle or vibey, ranging from
nearly indiscernible to extremely " grabby, " especially with the
fastest attack and release times.
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