Cube Synth review – additive synthesis for iOS from VirSyn

Download from iTunes App Storecube synth logo

If you have been around computer-based music production for any length of time, VirSyn will be a very familiar name as the company are well-known for their range of plugin virtual instruments and effects for desktop computers. They are also carving out a similar collection of iOS music apps and I have reviewed their Harmony Voice, Addictive Synth and AudioReverb apps previously on the blog.

The latest addition to the VirSyn iOS product line is Cube Synth (UK£6.99). Cube Synth’s synth engine is built around additive synthesis (in fact, VirSyn describe Cube Synth as an example of ‘spectral morphing additive synthesis’) rather than the more commonly used subtractive processes and, as the company also offer a desktop version of Cube, it’s fairly safe to assume that this iOS release is based upon the same basic technology.

With its interesting additive synth engine, Cube Synth is no 'me too!' synth app.

With its interesting additive synth engine, Cube Synth is no ‘me too!’ synth app.

The PDF manual for Cube has a rather useful explanation of the contrast between additive and subtractive synthesis and outlining the strengths of the additive approach (potentially at least) as a means of recreating, via synthesis based upon very simple sine wave-based oscillators, the complexities of any real-world sound. However, the problem with the approach – and the manual states this also – is that additive synthesis can require huge numbers of such simple oscillators (also known as ‘partials’) and this, in turn, requires the programmer to manipulate huge numbers of synthesis parameters to create a sound.

Cube Synth attempts to circumvent this downside by simplifying how users interact with and control this programming process by providing what VirSyn describe as ‘high level’ parameters; essential you tweak these high level parameters and, underneath the hood, they interact with all the lower level stuff so you don’t have to. That said, as shown below, if you want to dig a little deeper into Cube’s workings, then you can; this is not just a preset machine with a few mega-parameters to adjust.

So, with that background by way of introduction, what does Cube Synth actually look like and sound like? Let’s find out….

A basic cube

Cube Synth is supplied with an extensive set of preset sounds.

Cube Synth is supplied with an extensive set of preset sounds.

Cube Synth’s main user interface is divided into three areas; the upper bar providing access to key settings and options, the virtual keyboard at the bottom and, in between these two, the bulk of the display is dominated by an area containing individual controls for various sections of the synth engine. On its right-side, the top bar provides access to the help, record, tempo and ‘random’ (the twin dice icon) options, the last of which essentially randomizes the synth parameters to instantly create a new patch; just keep pressing until you get something that you like (yes, it can be a bit hit or miss but the occasional real gem can also appear).

The patch preset system is accessed via the panel located in the centre of the top bar; just tap and up pops a windows giving accessed to all the supplied presets organised into sensible groups. You can, of course, create your own presets and save these for later recall.

The four labels on the left-side of the top bar – 2D, Env, Arp and FX – are used to toggle the main control panel section of the display between four different views. As described briefly below (and as might be expected), the Env, Arp and FX screens provide access to controls related to envelopes, the arpeggiator and the various effects that Cube Synth includes.

Morphology

The default 2D display contains four sets of identical controls organised into four zones labelled A, B, C and D. Essentially, sounds within Cube Synth can be built from four individual sound sources, each being an independent synth engine and each of the four sound sources can have up to 512 of the ‘partials’ mentioned above. The ‘morph’ bit of VirSyn’s description of Cube Synth comes from the fact that, in various ways, you can combine these four sounds to create your complete sound and this can be done in real-time via the ‘square within an oval’ graphic in the centre of the 2D display.

The central X-Y pad shows the morphing envelope that controls how the sound of individual notes (shown here as green dotes) 'morphs' between the four different sound sources. The pure sound sources are positioned at the four corners of the pad.

The central X-Y pad shows the morphing envelope that controls how the sound of individual notes (shown here as green dotes) ‘morphs’ between the four different sound sources. The pure sound sources are positioned at the four corners of the pad.

This real-time morphing can be controlled via a user-defined envelope within the central X-Y pad (envelope morph mode) or by simply tapping and dragging your finger around (manual morph mode). You switch between these two modes by tapping the label just beneath the oval graphic. Equally, tapping the labels on the X or Y axis of the touch pad allows you to select other parameters that can be linked to the two axis.

It does take a little time to get your head around exactly what this central panel is doing and how its envelope-based control of the morphing process works. Thankfully, the PDF manual does a decent job of getting you started but it is actually quite instructive just to work your way through a few presets, play some notes, and simply watch the response of the small green balls that appear each time you play a note in the envelope morph mode. Whether you initially understand the details or not, this is an interesting system and clearly has a lot of potential when it comes to generating sounds that evolve though the duration of a note.

Additional parameters can be accessed from the 2D screen where you can configure settings for each of the four sound sources. here, the pan position of different frequencies for sound source A is being configured.

Additional parameters can be accessed from the 2D screen where you can configure settings for each of the four sound sources. here, the pan position of different frequencies for sound source A is being configured.

If you tap one of the letters in the 2D display – A, B, C or D – a further window superimposes itself on the 2D screen. Here you can modify the basic properties of each of your four sound sources. For level, pan, attack and decay you can basically draw in a curve showing the response of any of the possible 512 partials for that sound source as well as applying a filter and noise spectrum. These controls are easy enough to use and you can hear obvious changes in the sound as you experiment. However, while the PDF manual does introduce them well enough, don’t expect to instantly understand how they interact without putting some effort in.

While you can adjust an ‘morphing envelope’ within the 2D screen’s X-Y pad, to make more detailed adjustments, you have to go to the Envelope screen. This allows you to edit the X and Y axis of the envelope separately as well as defining a volume envelope. The latter is quite interesting in itself as you can add as many control points as you like (up to a maximum of 64) and therefore go well beyond the possibilities provided by standard ADSR envelopes. There are some weird and wonderful possibilities available here but don’t expect it all to make instant sense; working out how these various controls interact – and how they link to controls in other sections of the interface – does require some trial and error experimentation. That said, the results are fascinating and there are sound possibilities available here (although not all of them obviously musical) that I’ve not heard from any other iOS synth engine.

The Env screen provides access to further parameters and allows detailed editing of the 'morph' options.

The Env screen provides access to further parameters and allows detailed editing of the ‘morph’ options.

A number of other parameters not linked to the sound modulation options are contained within this screen. For example, you can adjust the number of voices (from monophonic to 8-note polyphonic) and the number of partials used in each of the four main sound sources (a higher number generally results in more harmonically complex sounds but also uses greater CPU resources). This latter setting is useful if you find your iPad beginning to wheeze a little within Cube Synth running alongside other apps.

Life after morph

Compared to the Env screen, the Arp and FX screen are more straightforward affairs. The arpeggiator offers up to 32 step patterns and you can specify the note, accent, octave, key and note ties using the five lanes. Each Cube Synth patch can have an arp pattern saved with it but it is also possible to create individual arp pattern presets. There are some other nice options here for setting the arp pattern, step interval, adding swing, the degree of accent applied and the note lengths used in each step (via the Gate Time knob). This is a neat little arpeggiator.

The Arp screen provides a rather neat arpeggiator.

The Arp screen provides a rather neat arpeggiator.

In terms of effects, the FX screen offers EQ, phaser, delay, overdrive, ensemble, chorus and reverb options. These sound good and, in the main, the app strikes a sensible balance between ease of use and level of control. And while it might have been nice to see a few additional options with the overdrive effect, thankfully, it does offer something rather warm and smooth rather than bit bashed bumble bees. The FX screen also allows you to toggle the virtual keyboard between two key widths; the wider one gives you just over an octave and would suit those with larger fingers. The ‘Q’ button is also useful. When on (lit), the keyboard acts in a conventional fashion. However, if off, you can slide your finger across the keys to get continuous pitch change (rather than stepped as you cross the boundary between keys). This is suitably weird but also a lot of fun.

The A, B, C (& D) of cube

Given the structure of the synth, its programmability and the various arp and FX options, just what exactly does Cube Synth sound like? This is actually quite a difficult question to answer. First, it’s worth saying that the ability to ‘morph’ between the four sound sources does provide plenty of scope for evolving sounds. This does, of course, mean that Cube Synth is particularly good for pads and, if you wanted a source of sounds for a disturbing sci-fi film score, this would be a suitable place to start.

Cube Synth's effects are easy to use and provide plenty of further sound creating options.

Cube Synth’s effects are easy to use and provide plenty of further sound creating options.

Equally, if you are in to sound effects design, Cube Synth provides plenty of scope for that. Indeed, the presets include some excellent examples that transition from harmonic/musical and well over into the weird and unsettling.

There are also some nice keyboard-style sounds amongst the presets; various soft and warm piano or organ sounds plus some with a more metallic or abstract edge and Cube Synth also does a good turn at percussive sounds with some particularly nice bell-like sounds possible.

The app include preset sections for both lead and bass sounds and, while there is some really good material amongst this lot that demonstrates a broad sonic palette, what it doesn’t really suggest – at least, not within the currently supplied preset selection – is that Cube Synth does outright aggression. Compared with something like Arctic ProSynth that I also reviewed recently, Cube Synth is perhaps less ‘in your face’. The sounds are interesting, engaging and evolving but perhaps more suited to more abstract and subtle musical styles than something like Arctic ProSynth or Thor, both of which would be more at home on the dance floor. This is absolutely not saying that one is good and the other bad – simply that they are different and would suit different musical contexts.

Cube Synth provided Audiobus support and this worked well during testing with Cubasis.

Cube Synth provided Audiobus support and this worked well during testing with Cubasis.

Cube Synth has Audiobus support and sits quite happily in the Audiobus Input slot. I was able to record the audio output from Cube Synth into Cubasis without any difficulty. Equally, I was able to send MIDI data to Cube Synth both from other iOS apps and from an external MIDI keyboard. Rather oddly, Cubasis recognised Cube Synth as Addictive Synth (one of VirSyn’s other iOS synth apps) in its MIDI track Routing panel (as did MIDI Bridge) but it worked fine.

As far as I could see, Cube Synth doesn’t yet support MIDI out. This is not a major issue but it does mean that you can’t record with the benefit of the app’s various keyboard scale modes that can be configured via the Env screen. This is similar to a number of other apps in restricting the notes available within the keyboard to choose in a particular key/scale combination and is a considerable help in reducing unwanted notes. The recording option within the app works well enough and you can share recordings via the audio pasteboard and iTunes file sharing. Presets can also be exchanged via iTunes.

In summary

The sounds Cube Synth generates are rich and detailed and, with the ‘morph’ options, it is possible to create a real sense of movement to the textures. For me, where it really excels is in pads and, in particular, somewhat abstract soundscape-like tones. For musicians into ambient composition or wanting to crossover into sound design territory, Cube Synth would be a very useful sonic tool. However, if you are mainly in to house, techno, dubstep or other full-on dance styles, while Cube Synth might provide some occasional seasoning, I think there are more obvious choices you would turn to for those types of bread and butter sounds.

Cube Synth's keyboard also provides a key/scale option so you can avoid some of the duff notes that virtual keyboards can often be prone to.

Cube Synth’s keyboard also provides a key/scale option so you can avoid some of the duff notes that virtual keyboards can often be prone to.

My only other observation would be about programming. VirSyn have provided an excellent PDF manual for Cube Synth that explains the nuts and bolts of its operation – and the basics of the synth engine – very well. However, despite that, unless you are just happy to start with a preset and tweak or really do just like experimenting to see where it might take you, I suspect most new users will find it takes a considerable time to really feel they understand how Cube Synth’s sound engine works and how the various parameters interact to create the final sound. It’s not that the controls themselves are difficult to use – far from it, the interface is well-designed – but that the additive synthesis approach will be less familiar to many users and the nature of the synth’s parameters will take time to fully appreciate. Cube Synth sounds great from day 1 but don’t expect to feel fully in command from a programming perspective without putting in some effort.

Cube Synth is an interesting app. The additive synth engine undoubtedly gives it a distinct ‘voice’ when compared to many of the subtractive-based synths that dominate the virtual synth world (including iOS). On these grounds alone, many iOS synth heads would probably consider adding Cube Synth to their app collection. And at UK£6.99, the price of accessing this somewhat different take on the world of iOS synthesis means that almost anyone could afford to give it a shot.

Cube Synth


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    Comments

    1. Excellent written review! This is how a review should look like. Going through each part of a synth, explaining what it is and how it works, the interface and so on. And a “section” with the subjective views on how it sounds and all that. A lot of reviewers tend to be more like “you got your oscillators here and there be some filters there, now let’s get to the review, how does it sound?”. Hope that made sense lol. Anyway great read!

      I’ve haven’t spent that much time with it yet. I like the pads, can do some very lush and warm-ish stuff. But (in contrast to the dense pads) with most other type of sounds it got this thin, kinda metallic “shimmery” timbre to it all. Can’t quite put my finger on it, I guess it’s something inherent to additive synthesis. Not sure I like that, but the arp/seq in conjunction with the env settings can obviously take that sound and spit something cool, rhythmic etc stuff on the other end.

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