VirSyn Tera soft synth for iPad reviewed

Over the past few years, VirSyn’s iOS apps have put the focus squarely on additive and FFT-centric synthesis tools. All of these apps have been extremely useful and great fun to use, so when Tera—their iPad take on modular synthesis—was announced, I was eager to take it out for a spin.
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Over the past few years, VirSyn’s iOS apps have put the focus squarely on additive and FFT-centric synthesis tools. All of these apps have been extremely useful and great fun to use, so when Tera—their iPad take on modular synthesis—was announced, I was eager to take it out for a spin.

The first thing that caught my eye was Tera’s clean, almost ARP-like design. Unlike their previous forays, Cube and Addictive Synth, Tera doesn’t rely on fancy visualizations of spectral data for its interface. Instead, it relies on familiar modules with sliders and knobs for adjusting parameters. Eschewing multiple pages and sub-menus, most of the parameters are accessed via a horizontally scrolling front panel that would be several feet long in the physical world. This approach is extremely efficient in practice, with the caveat that playing the onscreen keyboard while fiddling with parameters can be a bit awkward—which makes Tera’s extensive MIDI implementation a huge asset. This app virtually begs to be played via a connected keyboard or in the context of an Audiobus or InterApp sequencing environment.

Since the basics of Tera’s architecture are fairly standard (three oscillators, multimode filters, arpeggiator, integrated effects) let’s talk about the features that set it apart from the panoply of subtractive synths for iOS.

First up, there’s a very cool “waveguide” module that relies on a tuned delay configuration that’s great for quickly whipping up Karplus-Strong patches. For those unfamiliar with this approach, it’s one of the earliest forms of physical modeling and excels at emulating plucked strings. In fact, it’s almost impossible to avoid generating Clavinet-like patches with this approach, but having it integrated into Tera’s engine dramatically improves the synth’s sonic range.

Another exotic module in Tera’s arsenal is called a “sub-harmonic oscillator.” This isn’t your father’s sub-oscillator, as it doesn’t generate a square wave an octave or two under the first oscillator. Instead, it produces a “mix of six pulse oscillators with a frequency ratio of 1:2:3:4:5:6,” according to the manual. In practice, this sounds like a harmonic cluster of pulse waves, with the pulse width governed by the phase settings in oscillator 1. In any case, it’s a unique sound that would take a bit of programming to simulate on other synths, so it’s a welcome addition here.

The ring modulation section is also quite flexible, as it allows you to select from a wide variety of tone generators for its inputs, including the sub-harmonic oscillator, waveguide, noise generators, or even submixes of oscillators or the outputs of the filter modules. Modular indeed!

Speaking of the filter modules, in addition to the standard pair of multimode resonant filters, Tera includes a highly customizable formant filter bank with three adjustable bands that can be switched between peak and notch modes. This filter delivers truly exotic effects that transcend the usual vowel sounds, though you can conjure those too, if desired.

Tera’s audio resources would be really cool in themselves, but VirSyn includes some very deep modulation resources that give this synth a lot of authority in the modular synthesis area. Pretty much every parameter—even subtle items like the Q (bandwidth) of individual formant bands—can be modulated by its four envelopes, four LFOs, four multistage tempo-synced envelopes (with up to 64 stages!) and the usual complement of MIDI CC sources. Combined with its insanely flexible audio routing and unusual array of synthesis tools, this app really earns its modular street cred.

Adding its other iOS amenities, like audio recording with copy/paste, SoundCloud integration, Audiobus, InterApp functionality, and the ability to export preset files to iTunes file sharing, and you’ve got a real winner for a mere 20 bucks.

PROS
Highly configurable array of subtractive synthesis tools. Waveguide module delivers easy-to-use Karplus-Strong features. Sub-harmonic oscillator evokes the legendary Ondes Martenot. Formant filter includes three configurable bands. Lots of modulation options.

CONS
Scrolling interface can be awkward when used in conjunction with the on-screen keyboard. Performs best on newer iPads.

Bottom Line

Impressive modular synthesis tools for your iPad.
$19.99 | virsyn.com