Making a bass patch with Rob Papen’s Go2 virtual synth

Making a bass patch with Rob Papen’s Go2 virtual synth

Computer Music writer and reviewer Ronan Macdonald is taking a look at Rob Papen Go2 – the virtual synth offering from a synthesis supremo. (Download the free demo from the Go2 product page here). Over to Ronan…

“Packing the vast majority of its functionality and controls into a single window, Rob Papen’s Go2 is a powerful, professional soft synth with an interesting and endlessly versatile architecture that comes in at a deceptively low price.

While that busy, knob-laden interface might at first appear intimidating to the beginner, the layout is sensible, logical and easily learnt. And the experienced synthesist will have no trouble at all getting to grips with its retro-conceptual styling, once they’ve got their head around the intricacies of the amazing single oscillator that generates its raw tones.

Rob Papen Go2

A simplified version of that from stablemate Predator 2, Go2’s oscillator outputs two waveforms simultaneously, each selected from a list of 128. These take in the expected analogue essentials – Sine, Saw, Square and Triangle – as well as the unorthodox Rez, HalfSine, SineRez et al; White and Pink Noise; a variety of resampled additive constructs including vocals and organs; and 73 custom-designed Spectral waves.

This huge panoply of base signals becomes effectively infinite as the two waves are blended to create hybrid shapes, with the LFO-modulated Symmetry parameter skewing the resulting waveform, and the Sub oscillator underpinning it with a sine or square an octave down.

Beyond the simple volume-based ‘Mix’ blending option, Waves A and B can be brought together additively or via wavetable interpolation, or routed for FM, ring modulation or waveshaping. The whole thing can be doubled and detuned, too, for a pseudo-dual-oscillator setup.

The modulation of the Oscillator Morph control is key to unlocking Go2’s exceptionally acrobatic sonic potential. A full and comprehensive battery of mod sources is available for this and other parameter-animating tasks, including three envelopes, an LFO and a step sequencer; but the jewel in the crown is the awesome XY pad – see below for a tutorial on using it.

Also of note is the superb oscillator stacking system, which allows up to four unison voices to be detuned and panned as usual, or layered across specific pitches as any one of a wide range of preset chords. The same chord selection menu gets its own lane in the 16-step Arpeggiator/sequencer as well, for incredibly creative ‘one-note’ harmonic sequencing.

After the oscillator, Go2 provides two stages of filtering, the first a flexible resonant multimode circuit, the second a two-pole resonant high-pass for thinning out pad, lead and FX patches, and alleviating overbearing low-end in general. As we’ve come to expect from Papen, both sound thoroughly ‘analogue’, and the colourful Comb type is a welcome inclusion alongside the staple low-pass, band-pass and notch options.

From there, it’s on to the effects section, comprising Chorus, Flanger/Phaser and Delay/Reverb, each with a full complement of controls for shaping and polishing your filtered, modulated tones to perfection.

A low-budget synth with a big-budget sound, Go2 has no major shortcomings to speak of; but the best thing about it for me is the almost liquid plasticity of the oscillator, and the ease with which its hybrid waveform can be set in motion using the XY pad. Allow me to demonstrate…”

Walkthrough – Making a bass patch in Rob Papen Go2 with XY Pad oscillator and filter modulation

Why not download the free demo version of Go2 now to try these steps out yourself?


step 1

Here’s Go2 in its initialised state but switched to Mono Play mode and with the Amp Envelope Release lowered. It’s playing a bassline over a drum loop generated by Rob Papen Punch. In the OSC/XY section, top left, both oscillator waveforms – Wave A and Wave B – are set to Saw, and the Oscillator Morph slider, which mixes them, is at the top of its range, so that all we’re hearing is Wave A. Of course, at the moment it wouldn’t make any difference where Oscillator Morph was set, as both Waves are identical. 


Rob papen go2

First, let’s change Wave A. Clicking the Wave A menu reveals Go2’s extensive list of analogue, additive, noise and spectral waveforms. Select SqrRez for a far more harmonically interesting raw tone. Dragging the Oscillator Morph slider downwards mixes this with Wave B, which is still set to Saw – change it to Spec 31. Play around with the Oscillator Morph slider to get a feel for how the two waveforms blend.


Rob Pen Go2

The Morph Mode menu is currently at its default setting, Mix, which means the two waveforms are being blended based on volume – ie, crossfaded. The Morph, Inter and Range settings offer alternative blending methods, while FM, Ring Mod and WaveShape use Wave B as a modulation source for Wave A. Give each one a try, then return to Mix mode and set the Oscillator Morph slider to 50%.


Rob Papen Go2

Although Go2 is a single-oscillator synth, turning the Spread knob clockwise introduces a second, duplicated oscillator and increasingly detunes it away from the first. This is ideal for quickly thickening up the sound, as setting it to 100% demonstrates.

The second oscillator can be discretely pitched in relation to the first by assigning the Offset Modulation Source to the Osc Up Semi-Spread Destination in the Modulation Matrix, bottom left and setting the pitch in semitones in the Amount field. Here’s what it sounds like set to +12sm. 


Rob Papen Go2

Delete the Offset modulation assignment and return Spread to 0%. Now it’s time to get that oscillator moving with some XY Pad modulation. Start by setting both the X-Morph and Y-Morph knobs to 50%.

Now, moving the dot in the XY Pad offsets the Oscillator Morph parameter on both the horizontal and vertical axes – although the Oscillator Morph slider itself doesn’t move, you can see the morphed waveform change shape in real time in the display. At these settings, we get 100% Wave A with the dot at the bottom left corner, 100% Wave B at the top right, and the manually positioned Oscillator Morph mix (50/50) with the dot at the centre of the XY Pad.


Rob Papen Go2

The movement of the dot in the XY Pad can be recorded and played back. Start playback in your DAW, click the Rec button at the top of the XY Pad, and move the dot around. Click Play to see and hear the travelled path, looping in sync with the host DAW.

For my bassline, with its short notes, I switch XY Play Mode to Free, so that the modulation loops constantly, regardless of note input, rather than retriggering – I’m looking to modulate the whole phrase rather than each individual note. For sustained sounds, where you do want the modulation to be retriggered with each note, Poly or Mono are usually the more appropriate options.


Rob Papen Go2

Clicking the XY Pad Edit button reveals the recorded path as a series of connected points that can be dragged around to reshape the modulation. The Points, Space and Time menus enable adjustment of the number of points in the path, snapping of points to a background grid, and playback quantise. Right-clicking opens a menu of preset path shapes, and transformation functions – Flip, Rotate, Smooth, etc. Here, I’ve pulled a few points around to mess up my previously elliptical path.


Rob Papen Go2

The four mod amount knobs to the right of the XY Pad are assignable to any parameters within the synth, two each for the X and Y axes. Here, I’ve dialled in the low-pass filter, then routed the Y axis to its Cutoff and the X axis to Resonance, and raised the X-axis Volume modulation a little to narrow the variation in loudness between Wave A and Wave B.


Rob Papen Go2

My bass patch is now quite heavily modulated, but I can make it even madder using the Symmetry controls at the bottom left of the oscillator section. The Symmetry parameter shifts the centre of the oscillator waveform left or right, and can be cyclically offset by a dedicated LFO, the rate and depth of which are determined by the SMod and Speed controls. Here, I’ve left Symmetry at the centre point, but modulated it quite heavily at about 3Hz. The resulting movement is clearly audible and visible in the display.


Rob Papen Go2

My bassline now has plenty of harmonic action going on, but it needs to sound and feel a lot bigger. Turning the Sub knob clockwise mixes in a square wave sub-oscillator (anticlockwise produces a sine wave) for low-end solidity, while setting Unison to 3 and raising the Unison Detune and Spread parameters brings the width. The end result is a driving, wobbly ‘off-grid’ bass patch almost entirely defined by the modulation of the oscillator waveform and filter. It already sounds pretty good, and I’ve not even applied any effects yet.