SPITFIRE AUDIO BT PHOBOS
With EDM don BT onboard, top-notch sounds are a given, but how does this previously-Kontakt-only developer’s first plugin fare in use?
Dreamt up by electronica legend Brian Transeau and developed by Spitfire Audio, BT Phobos is “the world’s first polyconvolution synthesiser”, aimed specifically at cinematic composers and sound designers. It also has the distinction of being Spitfire’s first selfcontained plugin (VST/AU/AAX), marking a departure from the Kontakt libraries for which they’re known. Congrats, Spitfire!
Phobos is all about cross-processing samples pulled from a spectacular 20GB library (see BT’s grand repository), using the so-called ‘polyconvolution’. While regular convolution involves applying, say, a static impulse response captured from a hardware reverb effect to a signal in order to place it in that reverberant space, polyconvolution makes the convolver samples playable up and down the keyboard, polyphonically, each one generating a discrete, pitched impulse response for every note in real time that’s then used to convolve the source samples, which are, of course, also pitched.
Main Source
The convolution itself is controlled in the Convolution Triangle, each apex of which routes to one of the three Convolvers, with the four movable ‘pucks’ representing corresponding Sources. With a puck in the middle of the triangle, that Source is convolved by all three Convolvers, and by dragging it towards a corner, the ‘send’ amount to that Convolver is progressively raised. Send, for example, a pad Source to a drum loop Convolver and the pad increasingly takes on both the rhythmic feel and sonic characteristics of the loop, until the two become symbiotically intertwined, melding into a whole new sound. The keyboard ranges for all seven Sources and Convolvers are defined by dragging the ends of the range bars in the graph display at the bottom.
Each Source panel gives direct access to ADSR envelope and high-pass filter controls, and separate knobs for balancing the dry and convolved signals, while the Convolver panels enable tweaking of volume, pitch and HPF. Clicking a Source’s number (1-4) or Convolver’s letter (W, X,Y) opens its Controls page, housing further synthesis and playback parameters
“Send a pad Source to a drum loop Convolver and the pad takes on its rhythmic feel and sonic characteristics”
“Four LFOs are assignable to any and all parameters, along with the full list of MIDI messages and CCs”
(and repeats of the panel controls), including extremely high-quality timestretching and pitchshifting, Start Offset (with or without quantise), resonant high- and low-pass filtering and two gates – a normal one, and a ‘reversed’ one that passes the signal below the threshold.
Mapping and more
With its cinematic remit, modulation is a key part of Phobos’ architecture. Four LFOs are onboard, assignable to any and all parameters, along with the full list of MIDI messages and CCs; but each module only has a single envelope – we hope a few independent mod envelopes will be added at some point. Assignments are made in each Source or Convolver’s Mappings pop-out, where modulators can be set to scale their target parameters or set them absolutely, and ranges and response curves are edited. As you’d hope, the sends to each Convolver can be modulated and automated, although the Source pucks only animate with the latter.
It’s a solid setup, but really, we’d prefer a global modulation matrix showing all our mods in one place.
Visually, Phobos certainly comes across as cool and ‘serious’, but the sheer number of identical controls in the Mapping and Controls windows, the grey-on-black legending and the lack of ‘anchoring’ colours make it harder than it needs to be to navigate. It’s also only just on the right side of too small for comfortable use on a retina display – our ageing eyes can’t wait for the GUI scaling that Spitfire assure us is on the way in an imminent update. All that aside, ultimately Phobos is a straightforward, easy-to-use synth with an obvious and intuitive workflow.
Back on a critical tip, we’re mildly astonished at the total absence of effects – Phobos is positively screaming for at least a distortion module and master filter, if not also reverb, delay, chorus, phasing, flanging, etc. There’s also huge variance in the volume levels of the presets, which can lead to the odd speaker- -bothering surprise; and the CPU usage on our -top-spec test iMac was all over the place at times. Those last two issues will also be addressed in future patches, say Spitfire.
Mars attacks
The sounds yielded by the polyconvolution process at the heart of Phobos are very much along the same lines as what you get by loading an ‘inappropriate’ sample into a convolution reverb, but made musically meaningfully by the polyphony and per-note IR generation – it’s certainly a successful approach. Equally importantly, BT’s stellar soundbank gives the engine plenty of quality material to chew on, and playing around with combinations of Sources and Convolvers never gets boring or repetitive.
What Phobos isn’t really for are big basses, tearing leads and other upfront sounds of that ilk. No, this is an instrument wholly focused on producing complex pads, atmospheres, drones, ’scapes, textures, ambiences, rhythm beds and the like. From hyper-kinetic to slow and sinuous, sub-heavy to delicate, sparkling and pretty to stark and terrifying, clean and cutting to f**kedup and filthy, it’s an inspirational instrument that rewards experimentation and adventure.