its relative obscurity, the Sequential Prophet-VS was one of the most
innovative synths of the mid-’80s. Released just a year before the
company was sold to Yamaha (and products discontinued), the
Prophet-VS unleashed an entirely new form of waveform manipulation
for synthesists. Called “Vector Synthesis,” this method of tone
generation was based on four digital oscillators, each with its own
waveform and tuning, that could be blended in real time or via a set
of automation tools that blurred the line between envelopes and LFOs.
The results were similar to the PPG Wave’s ability to scan through
a wavetable and shifting timbres, but far more flexible, since the VS
was able to smoothly transition between a much wider variety of
newest iOS app iProphet is an impressive recreation of the VS sound,
incorporating nearly all of the original’s features into a much
more intuitive interface, and adding a few essential effects that
thicken the sound nicely.
The original Prophet-VS
oscillator topology is reproduced faithfully here. Each of the four
oscillators includes coarse and fine tuning for an array of 95 single
cycle digital waves that cover a lot of sonic ground and have a
distinctly vintage ’80s vibe. Once you’ve adjusted these options
for each oscillator, you can then mix and blend them via a virtual
joystick to create really deep textures or (with a little advance
Things get a lot more interesting
when you apply Arturia's visual implementation of the VS’
envelope-based mixer for the oscillator blending. Here, you can
specify five different joystick positions and then set the transition
times between each point, allowing you to shift smoothly between
waveforms and tunings. What’s more, this envelope can be set to
loop between a variety of positions, allowing for LFO effects. The
end results can range from shimmering animated pads to percussive
patches that quickly whip through timbre shifts in clever ways. While
there are other modern iOS synths that perform similar tricks, the VS
interface distinguishes iProphet from the competition.
From there, the rest of the
iProphet’s synthesis engine covers the classic analog/subtractive
territory, but with a few improvements and modern Arturia
enhancements. For example, iProphet retains the original’s
innovative five-stage envelopes for the filter and amp—each with
separate parameters for level and time--but with the enhancement of
being graphically editable. As for the filter, it’s got the
standard complement of cutoff, resonance, and envelope amount, but
Arturia also gave it modern multi-mode options. The tempo-synced dual
LFOs cover familiar territory, with controls for rate and the five
essential waveforms: triangle, square, saw up or down, and random.
Another enhancement is a
pin-based modulation matrix, evocative of the legendary EMS VCS3.
Here you can route the LFOs, envelopes, keyboard tracking, modulation
wheel, and iPad accelerometers to a variety of iProphet’s synthesis
functions. Interestingly, the depth of modulation is governed in a
semi-global way for each modulation source. For example, you can
route the filter envelope to the frequency of oscillators A and D,
but the amount will be the same for both. This isn’t a drawback, as
this “limitation” gives iProphet some extra character.
While iProphet doesn’t include
the original’s unusual arpeggiator, it does include its chorus,
along with an overdrive stage and a stereo delay. As for iOS
communication, there’s Audiobus, Core MIDI, Apple Inter-App audio,
and even Tabletop if that’s your preferred standard.
All in all, iProphet is a
knockout classic synth emulation for the iPad, and for a mere five
bucks, an obvious Key Buy.
recreation of the Prophet-VS vector synthesis engine. Intuitive
interface design makes managing oscillators and blending a breeze.
Multimode filters. Integrated chorus, overdrive and delay.
user-designable waveform tools of the Prophet-VS are not included,
nor is its innovative arpeggiator.
classic in your backpack.
$4.99 | arturia.com