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Rob Papen Blade

Software Synthesizer
By Paul Nagle

Is Rob Papen's Blade the cutting edge of additive synthesis?

The Harmolator parameters are mapped out on the XY pad, each note follows the recorded path of motion.The Harmolator parameters are mapped out on the XY pad, each note follows the recorded path of motion.

In theory, additive synthesis is simple, yet the challenge to put it at the core of a musician‑friendly instrument remains almost completely unanswered. Hoping to do exactly that are the team of Rob Papen and Jon Ayres, with their latest creation, Blade. This incarnation of additive synthesis generates its waveforms using 96 sine waves but remains true to the Papen tradition of being welcoming and easy to use. Might additive finally be ready to come in from the cold?

Sharp‑Dressed Synth

The single-screen interface is divided into nine logical areas, one of which is multi‑purpose and contains the arpeggiator, effects, free modulation connections and an invaluable spectrum display. Otherwise, all the synthesis parameters are laid out before your eyes, and this can be rather a lot to take in. With so much information, some of the knobs have been a bit squeezed, so it's helpful that the panel can be expanded to 150 percent of its normal size. Here's where a large monitor pays dividends, of course.

The result of all this is an interface that, despite being dark and brooding, takes almost no time to learn. I did have one problem with it, though: the glowing blue text. Although this can be turned off for the value fields, it's a permanent fixture on the panel, the fuzzy text indicating whether a particular section is active. While I enjoy seeing the world through a chemical glow as much as the next man, it's an assault on the eyes when you can't turn it off. Hopefully, an alternative skin will appear soon!

Where's The Harmolator?

A sine ripple pattern applied to the additive partials.A sine ripple pattern applied to the additive partials.

By now, most of us will be familiar with subtractive synthesis, in which harmonically‑rich waveforms are combined before being selectively filtered. Additive synthesis turns this idea on its head, creating sonic complexity by manipulating the levels of sine waves, known as partials. (For more information about additive synthesis, I can't think of anywhere better to start than our very own Synth Secrets: /sos/jun00/articles/synthsec.htm) In Blade, this manipulation is done by the Harmolator, a name that conjours up visions of dastardly conveyor belts, possibly with Batman or Robin strapped to them.

Some additive synths have featured more than Blade's 96 partials but if there's any impact on clarity and definition, it's more likely to be an issue for Batman's furry namesakes than for human hearing. The first partial is known as the fundamental and each successive partial is a multiple of the first's frequency. So the second is twice the frequency, the third is three times and so on. Instead of addressing the amplitude of every partial individually, Blade uses a series of controls that act on the entire spectrum. Could this streamlined approach open up additive like never before? Let's take a look at what's involved.

The Base knob is the logical starting point. It sets the frequency of the loudest partial, effectively the pitch of the additive oscillator. Next, the Range control determines how many partials are active. At its lowest setting, there's just one sine wave (the base), while higher values open up the harmonic sluice-gates. The Symmetry knob sets the roll‑off in level of harmonics above or below the base partial. Turned to the left, the effect is similar to a low‑pass filter; to the right, it's like a high‑pass filter. Already, with just these controls, you can produce waveforms such as conventional sawtooth waves and sharp digital ones as yet unnamed.

As I mentioned earlier, the Spectrum display is invaluable. This is because it translates every Harmolator parameter into visual feedback. Instead of searching for meaning in the manual, you simply tweak, look and listen!

The function of the next control, Timbre, varies according to the selection made in the 'Timbre Type' menu. Choose one of 16 preset types and the control alters the balance between harmonic and 'aharmonic' partials. Harmonic partials are the 'nice‑sounding' ones such as octaves and fifths, while aharmonic partials tend to be the weirder, less regular intervals. Audibly, the results lurch from rich and synthetic to hollow and organ‑like. When you opt for one of the large collection of Timbre Waves instead, the control becomes a balance between the current additive spectrum and the spectrum of the wave you picked.

Blade already takes the pain out of additive synthesis, but take the 'Easy' option and its panel is simplified even further.Blade already takes the pain out of additive synthesis, but take the 'Easy' option and its panel is simplified even further.If you're still wrapping your head round that, the following control can be regarded as light relief. The Even/Odd knob balances the mixture of even and odd partials. When it's turned clockwise, the even harmonics are reduced in volume and the sound is hollow and square in character. A turn in the opposite direction reduces the odd harmonics and produces a more saw‑like output, with the balance equal in the middle.

The function of the two Ripple controls is to remould the harmonic series into a less predictable shape. This is achieved by applying a number of basic waveforms such as triangle, saw and random, and 10 preset digital waves, to the partial amplitudes. You control the depth of effect and also its width (ie. how far along the spectrum it extends). The Ripple Type field sets the ripple behaviour and is either concentrated around the first or the base partial.

Moving swiftly on, the next pair of parameters, Harm and Harm Vol, introduce a second harmonic series of the same shape as the one you're working on. The difference is that these extra harmonics are shifted up or down from the Base. And, nearing the end of our rapid tour, Spread is provided for those times when the additive oscillator sounds rather thin. This is accomplished by adding two extra Harmolators with gradual detuning, and is one of several techniques for bulking up the pads and atmospheric patches this synthesizer will surely become known for.

Before leaving the Harmolator, I should mention that the additive synth is boosted by a sub-oscillator — either a square or sine wave. Unusually, you get to pick the sub's interval, even putting it an octave above the main pitch if you want. Furthermore, the sub-oscillator's tuning (and, in the case of the square wave, the pulse width) can be modulated in the free modulation section.

Why XY?

So far, the Harmolator has been revealed as a means of creating new waveforms, often of a buzzy, ringing nature. If not tamed, these static waves become wearing, but, fortunately, dynamic interaction with the additive parameters is Blade's forté. Central to this — and, indeed, the whole synth — is the XY pad. Fully deserving its size relative to the rest of the GUI, the pad maps the Harmolator parameters, plus cutoff and resonance, in a 2D space. I discovered that setting these values randomly, then moving the mouse around the pad, rarely failed to turn up a sweet spot.

However, finding a pleasing but stationary position for the mouse is only scratching the surface, because mouse movements can be recorded and played back. Playback direction is either once‑only or can be looped in forwards or alternating directions. You could even record a lengthy tour of sweet spots, because, within reason, recordings aren't restricted in length. They lose a little resolution if you make them minutes long, though! Recorded motions are triggered for each of Blade's 16 notes and may be synchronised to the clock of your DAW in a variety of intervals. Operating like an incredibly versatile LFO, it's no wonder the XY pad and its potential for dubstep wobbles and similar are emphasised by many of the factory patches. Further refinements include smoothing the playback motion or varying its speed using an external controller or LFO.

Instead of mouse‑chasing, you can turn to Blade's external MIDI assignment capabilities. My Kaoss Pad 3 proved great for this, although I occasionally resorted to the easy precision of stored directions such as circular orbits, spirals and squares. I couldn't help thinking that an iPad app similar to Omnisphere's Orb would have been the icing on the cake, but for now that's something you'll have to create yourself with a suitable MIDI control app.

Aside from the XY pad, full modulation of the additive parameters (and filter) is immediately accessible via pre‑defined sources: an LFO, an envelope, and note velocity. This method feels more inviting than the generic face of a modulation matrix (there's one of those too!), as everything is primed and ready to experiment with.

Filters, Effects & More Modulation

The arpeggiator can work like a step sequencer. Click the Key button and a pattern of up to 16 notes can be recorded/played back.The arpeggiator can work like a step sequencer. Click the Key button and a pattern of up to 16 notes can be recorded/played back.

After the Harmolator, Blade's synthesis enters familiar territory, in the form of a filter and distortion section. There are 14 filter types to choose from, including all the usual suspects, plus comb and vocal filters. Factor in 21 pre‑filter distortion types and you can see there's ample scope to rein in those zingy harmonics — or make them nastier!

To travel beyond the fixed modulation connections, there are two free envelopes and LFOs, plus an extra envelope and an LFO for pitch. When you want to paint in broader strokes, there's a small button marked 'Easy', which offers simplifications including replacing all the XY modulations with just two amount sliders and chopping Harmolator controls down to just three.

There are several small but perfectly formed extras worthy of note, beginning with the strum facility and chord recorder. When these two are combined, a single key can generate wild flurries of notes, each with their own dancing XY motion. Speaking of motion, I should also mention the arpeggiator, which, as in Papen's other synths, is a perfect marriage of features and friendliness. As well as rests, velocities and ties for each step, it includes a free modulation lane and can even function as a passable step sequencer.

Rounding things off, the dual effects section (configured in series) supplies effects for almost any occasion. There are 27 choices, including delay, reverb and chorus, plus yet more filtering and amp simulation, not to mention past favourites such as Gator, EQ and compression. The only significant omission is a rotary speaker effect, which I feel would liven up Blade's organs.

Bank Manager

When you're dealing with dozens of sine waves, organ tones are to be expected, but Blade is capable of far more. Starting at smooth and glassy, it crashes headlong into brash and spiky with only the slightest encouragement. Along the way, you'll hear echoing sequences and arpeggios, as well as atmospheric soundscapes, bells and eerie drones. But best of all is the seemingly endless collection of shimmering, shifting pads.

Following in the footsteps of Papen's other synths, the factory patches are grouped in banks, with no central database to house them. From the top‑line menu, it's possible to select banks and presets directly, or you can enter the Manager page, where all the banks are listed.

The notion of Banks came from hardware synths with their limited memories. Here another limitation is introduced: if you're building a new bank of original patches, it must be constantly saved. If you forget, and accidentally select a different bank, all the unsaved patches you were working on are lost! Can you tell this happened to me?

Blade is a synth that cries out to be programmed. That is not to say the factory banks aren't worthwhile; they contain some decent examples, especially pads and sound effects. However, they don't have that wide‑range of application I've come to associate with Papen's synths. Fortunately, once you strike out on your own, I doubt you'll feel seriously let down.


Blade is like a scalpel: so sharp it's almost painless! Via a dozen knobs and a few menus and buttons, the Harmolator could be the gateway to widespread additive addiction. The spectrum display plays a big part in this, giving real‑time insight into what each parameter does. I'd go so far as to say that Blade's synthesis is easier to understand than FM and almost as fast to program as subtractive synthesis — no mean feat!

Putting the complicated stuff out of reach doesn't automatically mean a lack of detail, either; it simply means you're not bogged down with decisions about the amplitudes of every individual partial. Still, it would have been nice to occasionally dig a little deeper (and, who knows, that might come one day). For now, I think the balance is about right.

Admittedly, the inclusion of an XY pad is not radically new but this version is audibly different, due to the additive parameters and the synchronised pad motion. Other than the lack of a central patch database, there's really only one aspect of operation to complain about: the glowing text.

Blade is quietly innovative, fairly‑priced and a real palate‑cleansing alternative to other synths. If you're still unconvinced, why not download the demo version and give those partials a spin?  


Camel Audio Alchemy offers a powerful blend of additive synthesis, resynthesis, granular synthesis and virtual analogue, amongst other synthesis types. However, it is more expensive and doesn't really compare for speed and ease of use. Of the limited number of other options that spring to mind, you could do a lot worse than dig around for a second-hand Kawai K5000S keyboard or K5000R module.

System Requirements

Blade runs as either a 32‑ or 64‑bit program for Mac or PC (good news for we Logic users keen to avoid the shaky 32‑bit bridge). It doesn't run stand‑alone, but in Blade's case, I think I'd be more interested in a stand‑alone version in hardware!

The supported plug‑in formats are VST and RTAS for Windows XP, Vista and Windows 7, while the Mac (OS 10.5 or higher) gets AU, VST and 32‑bit RTAS. The review system, on which Blade was pleasantly undemanding, was a Mac Pro running OS 10.6.8 with 12GB RAM and a 2 x 2.66GHz quad‑core Intel Xeon processor running in 64‑bit mode. The DAW Host was Logic 9.1.7.


  • Additive synthesis feels intuitive — at last!
  • Ideal for deep, evolving pads and rich, digital soundscapes.
  • Inexpensive.


  • User interface is a bit gloomy, and text way too fuzzy.
  • Bank method of patch storage feels rather dated.
  • Some precision is sacrificed, inevitably, for ease of use.


It's fair to say that additive synthesis has yet to take the world by storm, being typically viewed as lifeless and static or complex and difficult. Blade cuts through all the guff and establishes itself as an approachable synthesizer with that all‑too‑rare quality: a distinct identity.


£78.95 including VAT.

Time+Space +44(0)1837 55200.

Published July 2012