Recording - April 2017 - 38

Plug-In Outlet
Madrona Labs Virta
By Darwin Grosse

In previous reviews, I've been lucky enough to be allowed
to work with the two Madrona Labs instruments: the Aalto
analog emulator and the Kaivo physical modeling instrument.
In both cases, I described a system that was super-flexible,
allowed for serious exploration, and whose presets only gave
a glimpse of what could be done with the plug-in. So the short
version of the Virta review would be this: "everything I said
before, but times ten, and an effect"!
I don't think I've ever encountered a more astounding-
and sometimes confounding-piece of software in my life! It's
hard to even know what to call Virta: it's an effects processor,
but it can be MIDI- and OSC-controlled, so it is kind of
like a synthesizer-especially since it has oscillators, envelopes and other generators. But it can also get pitch and
envelope information from incoming audio, so it might be
a voice-controlled synthesizer. Except it can also affect the
audio, so it's probably a voice-controlled effect. Except it also
works great with things like drums and pads...
I suppose that in similar fashion to Madrona Labs' Kaivo
(reviewed December 2016), it may be best to think of Virta
as a set of modular tools (like a Eurorack modular synthesizer)
that can take almost anything as input, and produces some
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RECORDING April 2017

form of audio as an output. Not very specific, right? Let's dive
into some of what that can mean.
As I said, Virta has a dual-input system: it can accept MIDI
(or OSC, if you play that game)
as a control system, with support
for note, velocity, gate, aftertouch,
and three MIDI controllers. It will
also bring in audio, and you can
detect the audio envelope and
even attempt to decode the pitch of
the audio. Combining the two systems of external control allows you
to create either highly-controllable
or completely self-managed effects,
or anything in between.
Next up are a series of generators, which provide an LFO,
a pair of oscillators, and an envelope. The oscillator design is
pretty special. In "classic" mode,
it looks like a typical analog-style
oscillator. However, it has a second mode, called "vosim", which
creates vocal-like sounds with formant manipulation. The LFO and
ADSR envelope are typical for synthesizer modules, but are (again)
rather surprising to see inside an
effects unit.
At the bottom of the plug-in interface are the actual effects,
which includes a variable-band vocoder (called "Formants"),
a gate (with lowpass option for Buchla-like woody tones), an
ultra-tweakable delay, and an output module. The Formants
module is the star of the system, featuring a selectable number
of bands with modulation for shifting and spreading them out
or manipulating the filter peaks. Combine this with either the
MIDI or audio controls and you can really start changing up
the sound of the original signal.
The delay is a pretty standard affair, but with a twist-it
includes a pitch shifter as well the normal delay functions.
Literally every parameter can be modulated, which is where
things get interesting: you can start using the contents of the
audio input, or even external MIDI control, to manipulate
parameters like the delay time, feedback, and stereo spread.
Starting to imagine some odd possibilities? Well, they are
there for your picking.
That 'picking' occurs through the use of the patcher, which
is the center section of the plug-in. Practically anything in the
top row-the inputs and the generators-can be used as
modifiers for anything else, by drawing patch cable connections
from modulation output to control input.

Table of Contents for the Digital Edition of Recording - April 2017