VIRSYNTERA 3.1 (Mac/Win)

With so many great virtual analog synths on the market, finding the one that's right for you is getting harder. The ideal synth would include not only

With so many great virtual analog synths on the market, finding the one that's right for you is getting harder. The ideal synth would include not only multiple analog-style oscillators and a couple of resonant filters, but also other features that can take sound in new directions.

Calling VirSyn TERA 3.1 a virtual analog synth would be selling it short. Yes, it does virtual analog. Also on tap are FM and additive synthesis, rudimentary sample playback, waveshaping, formant filtering, rhythmic multisegment envelopes (four of them), and a couple of arpeggiators. The 16 multitimbral parts can be split and layered for monstrous thick sounds or kept separate to sequence a multitrack song. The effects are basic but useful. And let's not forget the built-in multitrack step sequencer.

TERA was reviewed in the April 2002 issue of EM (when it was known simply as VirSyn) and included in the article “Virtual Workstations” in March 2003. To save you the trouble of digging through back issues, this review will cover the program from top to bottom (though out of necessity I'll skip over some details). The new features in version 3 include simple multisample layouts for the oscillators, a second vowel-formant filter, a basic arpeggiator to supplement the more complex arpeggiation features found in the step sequencer, new envelope modes and stereo routings, new types of synthesis for the spectrum oscillator, an internal voltage-controlled amplifier for amplitude modulation, and numerous other goodies.

Lay of the Land

TERA can run in standalone mode or as a VST, AU, or RTAS plug-in. Installation requires only the code printed on the CD, with no online authorization. Both a printed manual and a PDF version are included. Installation in my PC went smoothly, although I had to copy the TERA DLL file manually into my VST folder.

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FIG. 1: TERA has everything the dedicated synthesizer fanatic could desire: knobs, modules, signal routings, waveforms, filters, complex envelopes, and more.

The user interface sports plenty of knobs and drop-down menus, but it lacks standard menu headers (see Fig. 1). The file menu is tucked away under a floppy-disk icon, and various areas have context-sensitive pop-up menus containing copy and paste functions. There's no undo command, and when you quit the program, TERA won't prompt you to save edited patches or sequences.

Because TERA's voice design is so complex as to be intimidating to the uninitiated, half a dozen simplified front panels are provided. Each of them sets out the necessary controls for a particular type of synthesis — virtual analog, FM, waveshaping, and so on. You can easily port the sounds created in these panels over to the main panel if you want to combine them with the other modules.

The factory sound set shows off everything from delicate harp and glassy piano to massive pads, delicate washes, funky rhythms, frightening special effects, distorted and vintage leads, solid and colorful basses, classic keys, strings, organs, electro percussion, and plenty of presets that defy categorization. It's a bit tricky to get an exact count of the included programs, because they're stored in 27 different bank files, many of which are less than half full. More than 35 MB of sampled waveforms are supplied, some acoustic and some borrowed from VirSyn's other synths, Cube and Cantor.

Still can't find a sound that inspires you? Click on the Slot Machine icon in the upper right corner of the panel, and TERA will generate a random patch. I found a very high percentage of the sounds produced this way to be usable, probably because the program recombines settings from existing presets rather than rolling the dice with each parameter.

TERA can address eight stereo outputs when used as a VSTi within a host sequencer (see Web Clip 1). It also has its own 16-channel step sequencer with numerous features, including the ability to switch patterns during playback from a MIDI keyboard. The sequencer hasn't been upgraded significantly since version 1.0, other than gaining the ability to transmit MIDI to external devices (in Windows only). It's not truly competitive as a composing and recording environment.

Finding Your Voice

TERA has four sound sources: three standard oscillators and a more complex spectrum oscillator. In addition to two resonant multimode filters, it has a peak/notch filter and a morphing vocal-formant filter. Other signal-processing options include a waveshaper with preset and custom shaping functions, a wave delay for physical-modeling effects, and two ring modulators that double as VCAs.

In addition to MIDI control messages, the modulation sources include four standard DADSR envelope generators, four multisegment envelopes with up to 64 breakpoints each, and four LFOs. Up to 20 modulation routings can be programmed in each preset.

Audio routing is handled by a 5-input mixer that produces both a full mix of inputs 1 through 5 and submix outputs of 1 through 3 and 4 and 5. With so many audio inputs to choose from (the oscillators, the filters, the waveshaper and ring modulator, and so on), having a larger mixer might seem useful, but in practice I found that I never ran out of mixer channels before I achieved the sound I was aiming for.

Each preset includes distortion, delay, and chorus and flange effects, which are all fairly basic. In addition, TERA has a global chorus and reverb, which are shared by all of the multitimbral parts. Given how much RAM most computers have these days, it's unfortunate that TERA's delay lines are capable of no more than a single quarter note of synced delay at a tempo of 81 bpm or greater. The maximum delay time is 749 ms.


The three standard oscillators give you a choice of 64 preset waveforms, as well as custom wave and multisample options. The custom wave is designed in a window where you can specify the amplitudes of more than 200 partials, though only partials 1 through 32 can be edited individually (the others are grouped). TERA antialiases the composite waveform, so playing up the keyboard after choosing lots of high partials produces no artifacts. You can generate six detuned copies of any wave except the user samples using the 6x button and its associated Spread knob. All of the single-cycle waves, even those you design yourself, can be made more colorful with wave modulation (equivalent to pulse-width modulation, for old-school analog aficionados).

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FIG. 2: Multisample playback has been added to the oscillators in TERA 3.

The multisample setup is bare-bones but functional (see Fig. 2). Though creating a realistic multisampled electric piano is beyond TERA's reach, sampled drum kits work well, with the added advantage that you can process the samples through TERA's filters, waveshaper, and other processors. You can use up to 16 keyboard zones, each of which can hold two stereo samples. The two samples in a zone can be crossfaded using Velocity, the mod wheel, or Aftertouch. You can switch looping on or off (globally, not per sample), and a loop crossfade parameter (also global) will help smooth out the loops. Loop start and end points can be adjusted by a percentage; the same settings will be used for both samples in a given zone. Because of the limitations of the looping parameters, TERA shouldn't be thought of as a substitute for a full-featured sampler. When you create a multisample, TERA conveniently copies the audio files to a new directory so that they'll always be available with the preset.

The spectacular-sounding spectrum oscillator is TERA's additive-synthesis engine. Its features are not too well documented in the rather terse manual, to the point where I thought one of the knobs wasn't working until I poked around for a while. You can draw two different additive spectra, called Osc A and Osc B, with the mouse. The Morph knob, which can be modulated, blends the two. Each of these virtual oscillators passes through its own filter, which can have up to 128 peaks and notches across the frequency spectrum. Filter contours are also edited graphically. The result: individual partials can change amplitude as you play up or down the keyboard, depending on whether they happen to hit a filter peak or a filter notch (or something in between). In addition, you can use the Spectrum knob, which itself can be modulated, to sweep the filter contours up and down. The effect can be both complex and beautiful in a shimmering electronic way, though it's hard to describe in words (see Web Clip 2).

The spectrum oscillator can produce up to six detuned signals for a truly broad sound. Here's where it gets tricky, though: there are two Spectrum knobs, and the second does nothing unless you choose one of the modes that output multiple signals from the spectrum oscillator. At this point, the spectrum of signals 2, 4, and 6 can be swept separately from 1, 3, and 5. The outputs of signals 1 through 3 and 4 through 6 can be used as inputs for any module that has an audio input (a filter, for example). This is a bit confusing because the signals are labeled Spectrum A and Spectrum B, which has nothing to do with Osc A and Osc B mentioned earlier. What's cool about having three detuned signals in each of the two outputs is that they can be assigned separately to the new aux left and aux right inputs in TERA's final amplifier stage, thus producing a very rich detuned stereo image.

A new feature in version 3 is the addition of Walsh, Wavelet, and Operator modes to the spectrum oscillator. The manual doesn't explain these, but they have distinctive colors. Not new, but welcome, is TERA's ability to play in any tuning by loading Scala tuning files when it's launched (see for more on Scala).


The two multimode filters in TERA are fairly standard and can run either in series or parallel, depending on what input you select and where you send the output. There are eight different filter modes and an input overdrive knob for soft distortion. Each filter is built internally of two subfilters in series, and a Shift knob changes the filter response by moving the cutoff of one of the two subfilters.

But that's only the start of the filtering fun. The Formant Filter module provides three peaks or notches, each with its own frequency, depth, and resonance controls. You can modulate all of these parameters, for example, using an LFO to produce slow formant sweeps. The Terrain Filter module is for morphing between your choice of vocal vowel formants (A, E, I, O, and U). It also includes resonance and cutoff knobs.

The Waveshaper module has 15 preset shaping curves and one that you can design yourself using TERA's additive overtone editor. You can set and/or modulate the level of the shaping function. This module can turn an unassuming sine wave into a rich tone.

The Wave Delay module is more mysterious and not as easy to use. It's a fast delay line with feedback and is capable of producing tones that change slightly from note to note. It's also capable of producing unexpected loud peaks on random notes. Noise and custom waveforms with just a few overtones make good inputs, and controlling the input and feedback levels with multisegment envelopes can produce buzzy pulsing rhythms. I'm still not sure what to do with this module, but I like the factory presets that use it.


TERA's modulation options are extensive. The most convenient way to set up modulation is to right-click on a knob and choose a source and amount in the little window that pops up. The routings you create in this manner (up to a maximum of 20) also show up in a matrix-modulation display. The latter has an additional feature: the depths of routings 11 through 20 are available as modulation destinations. This lets you do tricks like changing the depth of one LFO from another. Some standard forms of secondary modulation — LFO depth from mod wheel and Aftertouch, and envelope depth from Velocity — are included as single sources, so you don't need to use two matrix slots for them.

If you switch on sync for the envelope, its time values will vary depending on the tempo of the internal sequencer or a host sequencer, and envelope points will snap to a rhythmic grid when edited. This grid has no triplet values, which is unfortunate. On a positive note, you can save and load envelopes, and ten rhythmic templates are provided as factory presets.

The four LFOs are basic, with no delayed onset, start phase, or complex waveform options. They can sync to an external clock, and each can sample and hold the output of the previous LFO. The ability to smooth the random-waveform LFO is a nice extra.

In addition to providing a global time-multiplier knob that offsets all of the time segments of all four DADSR envelopes, TERA 3 lets you modulate each segment of each envelope. For instance, you can change release time from the mod wheel while changing the decay time in response to Velocity. I found that TERA grabbed the mod-wheel value to apply to release-time modulation at the beginning of each new note rather than when the release time actually began, which is less than ideal. I also wish more MIDI inputs were available in the modulation matrix. Note Number, Velocity, Mod Wheel, Aftertouch, and Pitch Bend just aren't enough.

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FIG. 3: You can find a mousable modulation surface in TERA''s 8D Access window.

TERA's unique 8D Access window provides a mousable control surface that you can use as another source of modulation (see Fig. 3). Each of the four diamonds in this surface has x and y data outputs, and each output can be assigned to a number of different parameters. (New in version 3 is the ability to use these routings in the simplified front panels.) A dot in each diamond shows its current output values, and a glide-time parameter gives the dots in the diamonds “ballistics” — they'll continue to glide after you release the mouse button. According to the manual, you can hold the Control key while clicking-and-dragging to move all four dots at once, but in fact, the keys to hold in Windows are Alt + Shift.

Solid Ground

If the huge variety of tone colors that a good synthesizer can produce sets your pulse racing, you owe it to yourself to take a close look at TERA. I've been a fan of the program since the original release, but I had stopped using it for a while because of a mysterious compatibility problem with my regular sequencer (Steinberg Cubase SX), which VirSyn was never able to duplicate. I was a little nervous when I installed the new release, but the problem has vanished, and I'm thrilled to be able to use this synth again.

The new features in version 3, while not groundbreaking, expand TERA's sound palette and make it easier to use. Very few software synthesizers offer this much sound-shaping power.

Jim Aikin is a synthesizer junkie. He writes regularly for EM, Mix, and other music technology magazines.


TERA 3.1

software synthesizer

PROS: Extremely versatile sound engine includes additive, FM, virtual analog, and other technologies. Highly patchable semimodular design. Syncable multisegment envelopes.

CONS: The documentation could be more informative.

5 = Amazing; as good as it gets with current technology
4 = Clearly above average; very desirable
3 = Good; meets expectations
2 = Somewhat disappointing but usable
1 = Unacceptably flawed