Ever since the release of Propellerheads' Rebirth-338 in 1996, soft synths designed around analogue architecture have endured and proliferated. It's not hard to see why. The immediacy of subtractive synthesis controls (especially when operated with a MIDI controller or DAW automation), coupled with their low cost in comparison to vintage or contemporary hardware, has proven irresistible to countless producers.
Soft synths employing virtual oscillators, filters, envelopes and LFOs vary enormously in price, quality and complexity; from the proprietary synths bundled with most DAWs, to freeware models, to "premium" launches from Arturia and Native Instruments amongst many others. One of the latest instruments to be released into this last category is Diva, from German company u-he (the corporate identity of its founder, Urs Heckling), who have a strong track record of great-sounding products, notably their Zebra synth and Filterscape dynamic filterbank.
The major point of contention with software subtractive synths—especially those intended as "authentic" emulations of expensive vintage hardware—has been the long-running debate over whether a piece of digital software can ever fully recreate the sonic nuances of a well-maintained analogue synthesizer. The success of contemporary hardware by the likes of Dave Smith and Moog prove that there is still a solid user base eager for the real thing. With Diva, u-he are attempting to deliver a product which sounds as good as a virtual analogue synth possibly can.
Diva is in fact an acronym: the synth's full name is "Dinosaur-Impersonating Virtual Analogue," which indicates the designers' aim to "capture the spirit of various classic analogue synthesizers"—the Dinosaurs of the title. This synth has been the subject of great anticipation in the weeks leading up to its eventual release, with a (discounted) public beta being made available in mid-November last year, and the final version following a month later.
Diva is installed in VST and/or AU formats, together with an optional—and very extensive—bank of presets. The first thing to note about this instrument is that it places a heavy burden on the host CPU, and so a powerful computer is required. This is down to the uncompromising design of its circuit emulators, specifically with regards to its filters which feature zero-delay feedback, resulting in a much more accurate representation of analogue hardware than the majority of soft-synths. As with other "hungry" synths, the user is most likely to experience problems when using rich, layered, polyphonic timbres with long release times and spatial effects (reverb/delay).
Playing more than a couple of notes with this type of sound on my new(ish) Macbook Pro resulted in horrific glitching and drop-outs; fortunately the designers have taken this into account, and provided four different audio quality options—from "Draft" to "Divine"—which allow the user to balance sonic accuracy against the processing power of their computer. This is a rare feature in software of this type, and an extremely useful inclusion, since one could use Draft mode during production and switch into Divine mode for final bouncing or rendering. It goes without saying that u-he encourage the use of Divine mode as far as possible, since it is here that Diva "shows her true talents and attitude."
The synth is also fairly hungry in terms of screen real-estate, almost filling a 13-inch display by default. Here too, the designers have considered the user's needs, providing seven options for resizing. Despite the wide array of controls and functions available, the interface feels uncluttered and well-laid out, thanks to the use of tabs for viewing different aspects of the synth's functionality (including an oscilloscope!). Diva's controls are extremely well-designed: double-clicking returns a control to its default/flat position, and trackpads or mouse scroll-wheels can be used for click-free adjustment of parameters.
A defining feature of Diva is that it is a semi-modular synth: the oscillator, filter and envelope units can be swapped out, so that "different" synths can be created by using different combinations of components. This functionality has been implemented elegantly and cleanly in a way that is far more intuitive than some other modular designs, which make a point of adhering to their hardware counterparts (for example, Arturia's Moog Modular V). With Diva, clicking the triangular tab at the bottom of each unit reveals a dropdown menu from which alternative components can be selected. In addition, the synth offers extremely flexible modulation routing, from the "front panel" as well as from the Modifications tab.
There are four variants available in the Oscillator, Hi-Pass and Main Filter "slots," and three Envelope units. The most luxurious of the oscillator units is the Triple-VCO, but each variant has its own strengths. The Dual-VCO, for instance, has features not found in the Triple, such as the ability of each oscillator to produce up to four wave types simultaneously. The same is true of the various filters and envelopes: each has different values and characteristics, and there is no sense that one is a "poor relative" of another.
The presets are a great starting point for exploring the synth; they offer huge variety and are organised into logical banks. While auditioning sounds, users can easily assign them "favourite" or "junk" status; it is also a simple matter to create and organise custom folders of sounds. There is a "MIDI Programs" folder, intended to allow users to switch sounds using Program Change messages—and presumably reduce the number of instances of the synth in a project—however during my testing I was unable to get this working satisfactorily.
Diva sounds and handles like a luxury instrument; the highly advanced (and CPU-hungry) circuit emulations responsible for the quality of its "analogue" sound are complemented by a number of sensible, user-friendly operational features which make the instrument a real pleasure to use. It's immensely powerful under the hood, yet can be used effectively by anyone with a basic understanding of subtractive technique. As always, experimentation is the best way to conquer the learning curve, but the manual (newly available with version 1.0.1) is detailed and helpful, and hints at features already in development for future updates. While not cheap, Diva is far from the most expensive virtual analogue synths I've used, and is certainly one of the best sounding and most flexible.