Call me a synth nerd—I've been called much worse—but I recently found myself browsing Vince Clarke's website. Quite aside from gaping at photos of rack after rack of vintage synthesizers, I was drawn particularly to the videos he's made showcasing the unique sonic characteristics of the synths he owns and knows intimately. If you are looking for a resource to show you the sonic differences between classic synths made by Sequential Circuits, Roland and ARP, to name but three, his site is a great place to start.
Why is this anecdote relevant to a review of XILS-Lab's new "performance synthesizer," Oxium? Well, very much like Vince Clarke, the good people at Xils-Lab are clearly obsessive about synthesizers. I've been hugely impressed by both their VCS3 and PolyKB plug-ins, so the idea of a flexible new software synth that offers a sound path of its very own instead of mimicking a particular piece of analogue history appeals greatly.
Right out of the box, it's clear that Oxium packs an impressive sonic punch. Presets are organized into types (e.g. lead, bass and sequences) and styles, which makes sounds searchable by genre. This makes tracking down a starting point child's play. But any synthesizer with this number of dials, switches and sliders deserves to be played with, and rewards follow quickly for those who dive in.
Oxium's structure will be familiar to anyone who understands analogue synthesis. That's not to say that there aren't some highly useful quirks here. There are two main oscillators and a noise generator, but the fun starts once you realize that the four waveshapes offered in each can be engaged simultaneously as well as separately. Some basic maths reveals that Oxium can therefore produce eight-oscillator sounds when both oscillators are activated, which is a mouth-watering starting point. The oscillators can be synced for harder-edged sounds as well as coarse- and fine-tuned for fatter, richer results. Dials for stereo spread, spread tuning and spread modulation are another unusual touch that let you add detail to the stereo image created by your oscillator sources. The latter of these offers a first glimpse into the extensive modulation options available through Oxium.
Below the oscillators are the next unusual feature—sliders to control interaction between the oscillators and the twin filters. The first three dials control the amount the noise generator and oscillators one and two feed into the main multimode analog filter, which lies further to the right. Between these, there's an assignable filter offering low-pass, band-pass and high-pass options, as well as a formant filter, again with amount sliders per sound source. You can leave this second filter blank if you want to bypass it. There are also buttons to reverse the filter path and a mute switch for the main filter.
This is an incredibly flexible system for chipping away at the harmonics of your massed oscillators. Above the filter cutoff and resonance dials lay three envelopes—one for the amplifier, one for the filter and one freely assignable envelope, all with classic ADSR parameters. There are three LFOs, too, and like the main oscillators, these can sum different waveforms. So rather than the traditional model of choosing a modulation shape and then deciding which parameters to interrupt with LFO movement, the shapes here can be a warped amalgam.
Modulation-wise, there is a dedicated pane for this at the top, which launches a routing page where a raft of assignments can be made. You're initially greeted with controls for tremolo, AutoWah and vibrato effects. You can select which LFO source will control these and use the dials below to adjust amounts. Similarly, there are assignments for mod wheel, pitch bend, velocity and expression, which brings the performance aspect of the Oxium to the fore. On the right-hand side, you can set up a further six source and destination routings, with dials between them to control amounts and the ability to invert assignments.
Oxium also features four of its own effects modules that can also be used together or in any combination. These are chorus, delay, phaser and EQ, with appropriate controls for each module. The EQ is interesting, as it corresponds to the choice made in the freely assignable filter section, so rather than simply finding individual bands with cut/boost and Q (bandwidth) controls here, you'll instead find cutoff frequency and resonance rotaries, which provides tighter control over tone-shaping.
Oxium includes one more significant feature, borrowed from Xils-Lab's own Le Masque delay plug-in: it has a grid, via horizontal and vertical axes, for creating running sequences or dynamic, tempo-synced effects. For example, to make dubstep bass where wobble speeds are clocked to tempo but change in speed from bar one to bar one, simply program the filter cutoff offsets you want with a different rhythm in each bar. Similarly, if you want your first oscillator to step consecutively from a closed filter shape to an open one and back again, independently of the second oscillator, no problem. The grid is powerful and rewards invention, but be warned that you'll need to spend some time getting your head around exactly how it operates.
I'm a big fan of Xils-Lab, partly because I like the quirkiness of their instruments. So when I first loaded Oxium, I wondered if the more conventional parameter set available here was compromising their leftfield ethos. My mind is now more than reassured that there's plenty here to keep serious programmers on their toes. The synth engine sounds great, but the quirks of combining oscillator and LFO waveforms, the incredibly extensive modulation routing and the grid options all combine to produce a hugely flexible, rich-sounding instrument.