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DB Audioware Quantum FX

Modular VST & Direct X Effects [Windows]
By Mike Bryant

A selection of Quantum FX's bundled effects running in Cubase SX.A selection of Quantum FX's bundled effects running in Cubase SX.

As well as a bundle of 50-plus effects plug-ins, Quantum FX provides all the tools you need to design your own.

Since Dave Brown released the freeware Tempo Delay way back in 1997, DB Audioware have quietly built a reputation for designing good-sounding dynamics plug-ins priced somewhat to the south of reasonable. Now the company has moved up a meta-step, releasing a modular system for building your own effects for use in both VST- and Direct X-compatible host programs. Before those of you with no predilection for musically tangential tinkering mutter something about 'geeks' and flip the page, consider that for 300 US dollars Quantum FX comes with three bundles of effects, comprising the Classic, Creative and Studio packs, with more individually downloadable from DB Audioware's web site. That is, to all intents and purposes, over 50 separate plug-ins, covering most of the conventional (and some not-so-conventional) usages. And if you require something wholly different, well, that's the point — you can have a go at building it.

They're not the first company to take this approach. DUY's DSPider TDM plug-in for Pro Tools has been around since 1998, and a host of modular soft synths boast powerful audio processing capabilities, from the shareware Synthedit to Native Instruments' much-lauded Reaktor. Perhaps the product with most in common on the surface is Sounds Logical's Wavewarp, a program that has been providing very advanced modular signal-processing facilities in stand-alone and Direct X plug-in formats for a few years now, albeit with a degree of depth that may intimidate some musicians. Nevertheless, I do think DB Audioware have found something of a niche with the Quantum FX package, available from their web site as a daintily sized 2.3MB download comprising a host plug-in, installed by default in both VST and Direct X formats, and the stand-alone Workbench application for designing and building effects.

Bench Work

The Workbench application provides a simple, sparsely populated interface, with intimidating functions almost conspicuous by their absence — particularly since most of the menu options are duplicated in the 11-button toolbar. One side of the workspace is inhabited by an undockable Explorer-like palette called the Library, which houses the modules and building blocks from which patches are comprised, and, refreshingly, these are presented with simple text names — no inscrutable array of icons here.

In use, Workbench should feel familiar to users of Synthedit or Native Instruments' Reaktor, employing as it does the same virtual-modular design whereby the plug-in's user interface is abstracted from the internal 'nuts and bolts'. Although the 23-page PDF manual is somewhat cursory, it does provide a short tutorial to get you up and running, and I found it very quick and easy to get started building some simple effects. This isn't to say that Quantum FX can't steal the hours in a day like nothing since the last Lord Of The Rings Special Edition box set — trust me, it can (see the Quantum Cookery box for details) — but the learning curve is actually very shallow, aided by the use of tool-tips that describe the functions of parameters and modules when you hover your mouse over them.

The first step to making a patch is to select either a mono or stereo input/output configuration, which opens a new Algorithm window in the main workspace. You can then drag modules from the library into the workspace and link them to the input and output objects with virtual patch cords, after which you should be able to audition your incipient effect by either loading a Wave file or activating a live input from your soundcard. One drawback to the latter option is that the Workbench program does not currently support the ASIO protocol (only Direct X and MME), so you might not be able to achieve a latency low enough to make the live input feel particularly 'real-time'. You can change the number and size of the audio buffers in the preferences panel, but low settings will inevitably tend to make the output signal less stable. I was able to use 16 buffers of 128 samples each with my Echo Layla24, which did provide a relatively unslothly feel, albeit with the odd glitch on the more heavyweight patches. I'm informed, however, that ASIO support in Workbench is planned for a future update.

Verbs & Modifiers

The reverbs are one particularly intriguing element of Quantum FX, and provide an education in reverberation for those uncertain about the basics of this notoriously tricky-to-design effect. The three reverbs provided in the Classic Pack all share the same fundamental 'basic-verb' core, comprising two arrays of four comb-filters mixed down through a single arrangement of four all-pass filters. On top of this template, Simpleverb adds a high- and low-pass shelving EQ, and Roomverb a pre-delay section. Gateverb is a little more complicated, using an envelope follower to tie the reverb time to the volume of the input signal, for all those cheesy drum sounds that'll probably have come back into fashion by the time you read this.

Roomverb consumed around twice as much processing power as TC's Native Reverb Plus — around 14 percent on my PC — and sounded rather more metallic and less smooth overall; I wouldn't recommend anyone pin their hopes on being able to use it as their main reverb. If you want to try improving the sound of the reverbs, building blocks comprising six, eight, and 12 comb-filter arrays have been provided, and various other techniques could be employed to increase the complexity of the reverberant sound. You might, however, end up with something rather too CPU-intensive to have much of a practical purpose if you take the 'more of everything' approach.

The Smallest Unit...

A good portion of Workbench's modules comprise 'Meccano'-type routers, switches, mixers, delays and sundry other tools to fashion your virtual signal path. Beyond these, there's a variable-wave-shape oscillator, a white-noise generator, and assorted controllers producing fixed or floating-point numbers, tempo, frequency and note signals. You can also use one- or two-operation math modules to transform control signals with simple arithmetic functions, which is useful for inverting controllers or linking them to multiple parameters, and much else besides.

Editing parameter values can either be done with direct mouse input or by opening the Properties panel and entering a numerical value. The Properties panel also lets you set the minimum and maximum movement range allowed for the parameter, and provides the option of making it visible in the effect's user interface by ticking the 'Show in plug-in' box. There also a Smoothing slider, which facilitates volume-spike-free preset changes by morphing one value into another over a definable period, though it's handy to be able to overcome this behaviour when manually editing values by holding down the Shift key.

The real 'sound' of the effects is defined in large part by the algorithmic modules, which consist of 12 varieties of filter, EQs, dynamics processors, and a dual-mode distortion saturator. Obviously it wouldn't be practical (or particularly desirable) for DB Audioware to allow you to choose from a range of virtual capacitors, diodes and resistors in configuring these modules, but there is a certain amount of fiddling that can be done to tailor them to specific functions. The compressor, for example, allows you to vary the softness of the the knee characteristic and the time period used to calculate the RMS peak level. Similarly, the limiter module lets you set the look-ahead and release times, and enable or disable auto make-up gain. There is also a side-chain compressor which adds a lot of potential for experimentation, though it's a shame that this can't currently be used to add proper side-chain capability to the plug-in from within your host program — a facility which DB Audioware's conventional Direct X DB-D dynamics processor, for example, does enjoy.

Quantum Cookery

I found that Quantum FX illustrated the difference between something that's easy to use and something that's used for something that's easy. To rephrase that, whilst the Quantum FX Workbench is streamlined and simple, building good-sounding and usable effects can be a complicated process. Because the program affords the user a tremendous amount of control in designing the signal path, linking parameters, setting parameter adjustment ranges, and so on, there are inevitably a fair few decisions to be made, and even a smallish effect built from scratch often presents several tens of parameters that impact the sound in greater or lesser ways. As a consequence, when attempting to stray from the beaten path I invariably worked through a number of iterations of whatever I was trying to build that were decidedly rubbish before stumbling across something good (and sometimes I never got that far!).

I certainly regard this as a positive testimony to the program's relative expansiveness rather than an indictment of it, and you always have the alternative approach of basing your own creations on the templates provided in the form of the bundled effects, which is in many cases easier and more practical.

One real bonus when going through the process of tuning and improving your modular creations is that you can use your VST or Direct X host alongside Workbench and dynamically reload your algorithms into the Quantum FX plug-in after having made changes to them. This makes it very easy to tweak your effects as you go along and audition them in a working context.

Building Blocks

In much the same way that Reaktor uses 'macros', Quantum FX is capable of embedding multiple layers of ready-made modular configurations — here termed 'building blocks' — into one main Algorithm, a technique which greatly simplifies the construction of complex effects. In the Algorithm workspace, a building block is distinguished from 'flat' modules by four little squares on its title bar, and a double-click reveals its own internal components for editing in a separate window. In this context, making parameters visible means they'll appear in its abstracted form (see screen shot, right), so you can control them from a 'higher' layer, or ultimately from the plug-in itself.

A good example of a simple but commonplace building block is the three-way crossover filter, which is comprised from two instances of the basic two-way module. Rather than have all these modules and virtual cables obfuscating the signal path of your Multi-band Rezo-Obliterator (or whatnot), it's much more elegant to save the structure separately and drag it into the main algorithm as a discrete element. In fact, you don't even need to do that in this particular case, since DB Audioware have provided the above example in the library, along with many others including delay lines, modelled guitar cabs, and a vocoder channel. You can embed whole effects to your heart's content in the same manner, creating huge, stacked arrangements of delays, filters, or whatever else takes your fancy.

The process of creating and editing effects in Workbench is greatly helped by the numerous 'building block' macros. The guitar amp simulator, for example, makes use of the 'cabinet selector' building block open in the foreground window; in the main effect algorithm, only the 'Cabinet' parameter is presented. The process of creating and editing effects in Workbench is greatly helped by the numerous 'building block' macros. The guitar amp simulator, for example, makes use of the 'cabinet selector' building block open in the foreground window; in the main effect algorithm, only the 'Cabinet' parameter is presented.

Knobs & Stuff

After you've finished designing your algorithm, Quantum FX presents a great deal of control over the visual appearance of its interface — the bit you see when you load your effect into the VST or Direct X plug-in. Opening the plug-in window in Workbench reveals a plain background populated with all the parameters that you have chosen to make accessible to the outside world. Editing it just requires pressing the Unlock button, allowing you to arrange the controls to your liking or choose different visual styles by browsing through the supplied graphics. You can even create your own custom graphics by replicating the layout style naming scheme of the bundled sets — not an easy task for the graphically illiterate like myself, but a satisfying one nonetheless.

Though perhaps frivolous from a musical point of view, I think DB Audioware have been wise to provide this level of customisability, since it adds another aspect to the value-added appeal of modular systems. Since the visual appearance of the bundled packs is quite understated, it wouldn't surprise me if some artistically inclined users step up to the plate to provide more varied eye-candy for everyone else to download (see The Sharing Sort box for details of DB Audioware's effects exchanging scheme).

The Effects

Loading the Quantum FX VST or Direct X plug-in initially presents an empty window bearing an Open button, through which you can browse nested folders of effects. I almost wrote 'presets' there, because with so much choice on offer it's easy to forget that each modular configuration is an entirely separate processor, complete with its own dedicated presets. These can only be created, edited or removed from within the Workbench application, but I encountered no problems loading or saving patches in the host application using the standard host-based preset-management system.

A whizz through the three packs of bundled effects makes for rather impressive listening. The Classic Pack provides several of each of the staples, such as delay, chorus and EQ, along with a few simpler effects like auto-pan and tremolo. There are also three reverbs, Gateverb, Roomverb, and Simpleverb, for more on which see the Verbs & Modifiers box. There's much to like here, in particular the wonderfully biting filtered delays. The real highlights for me, however, were the guitar amps, specifically Two-channel Guitar Combo. I thought this felt extremely playable, with very satisfying clean and overdriven tones. Bass players aren't left out either, with both a dedicated chorus and a good-sounding amp simulator.

The Creative Pack consists of 11 sound-bending effects based predominantly around the modulated filtering theme. These range from the fairly simple Touch-sensitive Flanger to the highly knobular Rez and Loadza-filters. Rez is a terrific sound-transformer, comprising four tuneable filters on a tempo-based feedback delay circuit, each with level and pan controls. Working out how the controls interact tonally is largely a case of fiddling around till pleasing sounds emerge, but emerge they do, in heaps. This is a superb tool for turning percussive material into complex, chiming loops, matched to whatever key you desire. Loadza-filters is a similar design, though bearing LFOs for each of its four untuned, one- or two-pole filters. The presets 'da beatbox' and 'bongo machine' describe its more rhythmic characteristics well, and it makes a perfect counterpoint to the melodic Rez.

Overall, whilst the lack of time-stretching and pitch manipulation may limit the appeal of the Classic Pack to fans of out-and-out sound-destruction, it does score highly on making beautiful, spacey sounds out of even the most unpromising material. Ambient Pads, Doppler, and Snipper are all appropriately named, whilst the sample and hold filter has the familiar synth sweeps and 'R2D2'-type bleeps covered nicely.

The 15 processors in the Studio Pack represent the more complex mixing and mastering tools bundled with Quantum FX, including a three-band compressor, a five-band maximiser, and a harmonic enhancer, along with many others. Of particular note is Vocal-hype, a combined compressor/de-esser/EQ, which, with a pared-down complement of controls, is a very effective tool for enhancing a dull vocal sound with the minimum of fuss. There's also a 10-band M&S EQ which is very useful for making fine adjustments to the stereo image when mastering tracks.

Given DB Audioware's experience at programming dynamics modules for mastering and broadcast applications, you'd expect those present in Quantum FX to be good, and indeed they are; smooth and pleasantly transparent even at high levels, with a lot of scope for subtle adjustment. These are thirsty processors, however. The four instances of the very CPU-intensive linear-phase crossover filter employed in the five-band mastering limiter contribute to it demanding around 38 percent of my laptop's power, and although this isn't something you'd whack on your sequencer's master output, it does illustrate the need for a reasonably up-to-date PC.

With regard to CPU load in general, the usual rule of thumb for modular systems applies: you get comparatively less mileage in this area than with plug-ins coded and optimised for specific tasks. Then again, you do get to see how your processor cycles get spent, and a peek inside the two-channel guitar combo reveals why it demands over a quarter of my PC's power, using as it does up to 27 assorted filters, two saturators, an expander and a limiter, plus boatloads of other stuff linking everything together. Eliminating the reverb section made it about half as thirsty at no cost to the basic sound — a good example of how you can tailor the Quantum FX plug-ins to suit your needs.

Like many conventional plug-ins, some of Quantum FX's modular effects do introduce a processing delay, usually in the order of 3 milliseconds for those that employ look-ahead limiting to prevent overloads. Version 1.02 debuted an implementation of Plug-in Delay Compensation (PDC), which I gather was not entirely straightforward for the developers due to the fact that the latency varies depending on whatever modular effect is loaded at the time. Since some host programs apparently aren't able to spot this dynamic latency change, DB Audioware also provide an option to fix the latency at a constant value — by default 12ms — to cover most eventualities.

The Sharing Sort

Users of Quantum FX can share new designs via DB Audioware's web site. This Loudness Maximiser is part of the downloadable Mastering Toolkit.Users of Quantum FX can share new designs via DB Audioware's web site. This Loudness Maximiser is part of the downloadable Mastering Toolkit. The modular, open-ended nature of Quantum FX makes it ideal for the kind of user participation that was (and is) such a big bonus for owners of Native Instruments' Reaktor, so I was pleased to see DB Audioware add a section to their web site dedicated to sharing effects and custom graphics. On its debut the site featured four new effects, including a fantastic vintage-style delay with ducking and pitch modulation. This comes closer than any plug-in I've yet heard to emulating the wonderful grunginess of my old DOD Echo Plus sampling delay pedal, though it can also sound good-good as well as bad-good.

Also more than noteworthy is Mastering Toolkit, featuring a five-band EQ and Loudness Maximizer along with an enhancer and stereo-width control. Although the default settings provide a handy one-stop-shop for instant loudness, it's capable of very subtle applications and gentle fine-tuning if required, and stands out as one of the processors that reminds me how good a bargain the whole Quantum FX package is overall.

Of course, the success of the on-line library depends ultimately on the software's users, and something tells me that effects-building might not boast quite as extensive an enthusiast-base as synth-building. Nonetheless, if Quantum FX becomes as popular as I think it deserves to be, we should see some interesting offerings emerge as users explore the potential of Workbench.

Quantum Quirks

Some of the effects exhibit clicks when either manually adjusting or automating parameters, and DB Audioware inform me that this can occur when a lot of recalculation has to be done between settings on certain modules. Certainly, there are some cases in Workbench when using the LFO or envelope generator to control such things as the delay length parameter on the all-pass filter is impractical, due to the glitches it tends to cause, and I suspect this may be why there's no phaser effect present in the bundled packs despite the fact that building one would otherwise be a simple matter. In the broader sense, there are often ways around this problem, and some of the parameters most prone to glitching — such as the bandwidth control on the linear-phase crossover filter — won't usually need to be automated anyway. Nevertheless, since this about the only sound-related complaint I can muster, I hope the programmers can suitably mitigate it in future releases.

Here, I've used the Workbench application to customise the bundled Two-channel Guitar Combo effect, removing the reverb section for lower CPU load.Here, I've used the Workbench application to customise the bundled Two-channel Guitar Combo effect, removing the reverb section for lower CPU load.

More generally speaking, I think it's fair to say that — perhaps in part due to the user-configurable nature of its design — Quantum FX appears a little less refined than most ordinary commercial plug-ins. For example, the meters remain frozen at their last positions when the music stops, and the knobs and sliders on tempo-sync'ed parameters often display the wrong value (although the synchronisation itself works fine). There also appear to be a few bugs present in version 1.02 of the software; I found that some effects loaded into the VST plug-in would crash Cubase SX in certain circumstances, though DB Audioware couldn't reproduce this problem, and nor could I on my Intel Celeron-based desktop PC. Moreover, I could work around it simply by using the Direct X plug-in in cases where automation wasn't necessary. I also found that Workbench would crash when I attempted to load algorithms with live input monitoring enabled, though this is most likely related to my specific Echo audio drivers.

Whilst in the grumbling groove, I also feel there are currently a few interface weaknesses in Workbench's Algorithm window that make putting effects together a bit slower, if not more difficult, than it might ideally be. Editing parameter properties is something that has to be done a great deal in the course of creating or altering an effect, and it's a bit cumbersome having to open and close the properties panel all the time. I think it would be a good idea if DB Audioware were to implement some kind of non-modal floating dialogue box, perhaps one which makes it possible to edit multiple parameters simultaneously. It'd also be nice to have a way of duplicating modules or groups of modules, so they didn't each have to be set up from scratch as they do when dragged from the library pane. I am, however, quite confident that this area will greatly benefit from user feedback, with which the developers strike me as quite engaged.


It's hard not to find Quantum FX impressive. The Workbench application is generally well-designed and provides an easy path into the potentially daunting realm of modular effects creation. Even when made easy, signal processing can take a fair bit of head-scratching and/or trial and error to get to grips with, and it's a testament to the designers that you hardly have to worry about actually using their program at all. At the same time it presents a broad blank canvas to those with the inclination to get their hands dirty, albeit one with a rather more conventional bent than the somewhat off-the-wall approach associated with NI's Reaktor.

Ultimately, though, Quantum FX's success is likely to depend on the sound quality of the DSP modules provided, and it does not disappoint. The dynamics modules, EQs and filters are all very good, and allow enough tweaking of obscure functions to please most musicians. Perhaps most importantly, the bundled packs include a good number of really excellent effects, and — the lack of time and pitch-manipulation tools aside — provide a very versatile selection. I'd consider the asking price of about £180 at the time of writing well spent even without taking Workbench into account.

Like just about all 1.0x releases, there is certainly room for improvement with the package as it stands; a few performance issues with some modules need addressing as of version 1.02, and a bit of spit and polish in the general UI department wouldn't go amiss. Ultimately, though, if you're looking for a good-sounding bundle of plug-ins that covers the most common uses and some more besides, you can't go far wrong. Add to that the huge potential of Workbench and the prospect of downloading user patches and graphics, and it's clear that Quantum FX is a program you won't outgrow in a hurry. Highly recommended.

Recommended Spec

  • Pentium III 800MHz, 256MB RAM, running Windows 98, 2000 or XP, with Direct X 8 installed.


  • Effects sound great, and the bundled packs provide a wide-ranging and versatile ready-made selection.
  • Workbench is easy to use and very powerful.
  • Allows for user add-ons and customisation.
  • Provided in both Direct X and VST2 formats.


  • Modular design means effects are generally more CPU-intensive then task-optimised plug-ins.
  • Some module parameters exhibit glitching when automated, which serves as a limiting factor on some potential modular designs as of version 1.02.
  • Workbench doesn't support ASIO for low-latency auditioning of effect algorithms.


Quantum FX is a well designed and implemented system that manages to combine great simplicity with tremendous potential. The quality and versatility of the bundled effects should ensure that its appeal extends well beyond the realm of dedicated effects gurus, whilst the latter are nonetheless very well catered for in the tinkering department.


$299; upgrade from any other DB Audioware product $199.

Published January 2004