GFORCE ImpOSCar 1.0.1 (Mac/Win)

Performance worthy of an Oscar.
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FIG. 1: The impOSCar''s main screen with keyboard and Harmonic Editor display at bottom left.

Some very convincing analog-synth emulations have been created, but until recently nobody had attempted to capture the sonic territory of the Oxford Synthesizer Company's OSCar. It was a quirky, utterly unique instrument that could sound like any synth from a PPG to a Minimoog or something totally unidentifiable, depending on how it was programmed. The OSCar's combination of additive synthesis capability, digital oscillators, dual analog filters, and somewhat bizarre aesthetics made for a unique user experience.

On hearing about the GForce impOSCar virtual instrument, I was intrigued by the prospect of multiple OSCars running concurrently with conveniences like computer control, LFOs locked to host tempo, full MIDI control, and polyphony. (The original OSCar was a 2-voice instrument. Designer Chris Huggett built one polyphonic unit with eight OSCar cards for eight voices near the end of the company's life. The prototype was later dismantled for parts.)


I installed the impOSCar on two Macs, a dual 1 GHz G4 running OS 9.2.2, and a 1.25 GHz G4 PowerBook running OS X (version10.3.4). I ran the VSTi version on the desktop machine and the Audio Units version on the PowerBook. (I also installed the impOSCar as a VST instrument on my 2 GHz Pentium 4 desktop PC and verified that it worked. This review, however, is based on the program's performance on the two Macs.) I tried the impOSCar in two hosts, Emagic Logic Pro 6 and Plogue Bidule, a free-ware, cross-platform VST/VSTi host.

Visually, the impOSCar is a mostly faithful re-creation of the distinctive black rubber and cream metal surface of the OSCar. The software version features two oscillators; two multimode filters; up to 16-voice polyphony; the ability to create additive synthesis waveforms; a monophonic, duophonic, or polyphonic arpeggiator; an LFO with six waveshapes; and an effects section with programmable chorus and delay. The delay (along with the impOSCar's LFO and arpeggiator) can be synced to host tempo.

The most obvious difference between the work surfaces of the impOSCar and its predecessor is the addition of graphic icons above the Osc 1 and Osc 2 Waveform, LFO Waveshape, and Filter Type controls. These help greatly when programming the instrument, because the control labels are fairly tiny on the somewhat small front panel graphic, which is not resizable.

When you first load the impOSCar into your host, its panel comes up without a visible keyboard. The Edit Mode knob determines whether or not the keyboard is visible directly below the control panel, whether the Harmonic Editor is displayed (in place of the Pitch Bend and Mod wheels), and if so, whether that display shows User Waveform 1 or 2. The knob also offers a fifth choice called CC, which causes numerical labels to appear above every knob on the impOSCar's panel. These are freely editable, and determine the MIDI Continuous Controller to which each knob will respond.


One of the OSCar's coolest features was its onboard additive synthesis capability. In short, you could build your own digital waveforms by adding up to 24 harmonics at various amplitudes. You could store these in the OSCar's internal RAM, and freely assign any of them to either Osc 1 or 2. However, when creating the waveforms you were flying blind. No LCD or computer interface was available to show you the current harmonic structure — there was only a tiny row of five LEDs, which didn't make for an intuitive experience.

With the impOSCar, the Harmonic Editor shows the relative amplitude of the 24 harmonics. You can conveniently edit each by simply dragging the mouse over the row of LEDs corresponding to the harmonic you want to edit (see Fig. 1). You can create any number of waveforms, which are saved as .hrm files and can be exchanged, along with the .sup setup file, with other impOSCar users.

The impOSCar also includes more filter modes than the OSCar. You can select LoPass 24db, BandPass 24db, HiPass 24db, LoPass 2 pole, BandPass 2 pole, HiPass 2 pole, LoPass//HiPass, LoPass//BandPass, or BandPass//HiPass. (The last three are parallel configurations of the two filters.) That offers considerably more flexibility than the original OSCar, and programming the impOSCar using the additional filter modes greatly increases the variety of sounds it can produce. (On the OSCar, the two onboard 12 dB/octave filters could be HPF, LPF or BPF, with an additional “no track” option that disabled filter keyboard tracking. A Keyboard Track control on the impOSCar can achieve the same result.)

The OSCar's Filter Drive control, which required a combination of buttons and knobs to access, is given its own panel space on the impOSCar. It determines how hard the impOSCar's oscillators drive its filter, which has a huge effect on the sound of any patch. The more Filter Drive, the harsher the sound gets.

As mentioned earlier, the Separation control from the original OSCar is present here. The impOSCar's two filters, though they can't be modulated separately, can have their cutoff frequencies spaced by the Separation knob to create the distinctive formant effects that have come to be associated with the original OSCar. With the inclusion of the additional filter modes, this control takes on even more programming power. I had a lot of fun discovering the effect of the Separation knob on the new filter modes, and a number of interesting new patches were the result.

I created a dual-oscillator patch with a shimmer effect and changing tone using a short, percussive amplitude envelope and subtle filter modulation (see Web Clip 1); re-created a classic OSCar bass patch with a medium high filter Q (see Web Clip 2); and programmed a punchy sweep patch, again using both oscillators, high filter EQ, and LFO filter modulation (see Web Clip 3).


The most valuable advantages of the impOSCar over its hardware ancestor are polyphony, interface improvements, and sync capabilities. I was amazed to hear polyphonic OSCar patches and take creative advantage of the impOSCar's programming abilities. Onboard delay and arpeggiator sync made things even more interesting. I found myself creating all sorts of evolving drone textures that locked to the music I was working on. The user-created waveforms take on an entirely different character when played polyphonically, approaching PPG territory in sonic character. And of course it's great to have the ability to name patches and waveforms. I also appreciate the impOSCar's drag-and-drop functionality for .sup and .hrm files as well as for loading patches individually or in banks,

The impOSCar allows its controls to be addressed via user-assignable MIDI Continuous Controllers. These assignments can be stored to the .sup file and interchanged when using the impOSCar with various hardware control surfaces. The impOSCar also responds to MIDI Program Changes. If you already own an original OSCar with MIDI, GForce Music has a program that lets you to dump OSCar patches to your computer and load them into the impOSCar.

I had no problems with MIDI response on the impOSCar. A fun part of the process was sequencing parameter changes for many of its controls in Logic, something that had not been possible on the original. That is a powerful tool for creating shifting, animated sounds.


I A/B'd the impOSCar's sound with the OSCar's using the original factory patches. I also re-created some of my user waveforms from the OSCar manually on the impOSCar to see if I could hear a difference.

After a lot of scrutiny, I can report that while the two are not completely indistinguishable, to my ears the impOSCar's sound comes extremely close to that of the original. I found the original OSCar sounds somehow weirder, more digital, and quirkier than the impOSCar, which actually seemed fatter and slightly more modern sounding to me. Overall, however, it did an excellent job of emulation (particularly in the filter department).

The impOSCar captures the overall character of the original in virtually every way. I may only have noticed differences because I've had the original instrument for so many years that I'm very tuned in to its particular character. Overall, I very much liked the sound quality and character of the impOSCar and found that its musicality and power quickly made it indispensable.

The impOSCar comes with a printed manual and an Extras .pdf file as well as a tutorial video, which is helpful and clear, providing step-by-step instructions for using the most important impOSCar functions.


The impOSCar largely succeeds in its mission of faithfully re-creating a true classic synth. It also is a musical and extremely flexible instrument in its own right and can easily find a home in a wide variety of contexts. I had no stability problems whatsoever, and found it to be an extremely pleasant synth to program and play. I highly recommend it for anyone looking to add a powerful and unique synth to their virtual-synth collection.

Peter Freemanis a bassist, composer, producer, and mixer living in Los Angeles. He's worked with John Cale, Seal, Shawn Colvin, Jon Hassell, and L. Shankar, among many others.

Minimum System Requirements

impOSCar 1.0.1

MAC: G4; 64 MB RAM; Mac OS 9 or OS X 10.1

PC: Pentium II; 64 MB RAM; Windows 98 SE, 2000, ME, or XP



impOSCar 1.0.1 (Mac/Win)
software synthesizer



PROS: Excellent-sounding plug-in faithful to original OSCar. Cross-platform. Various sync capabilities. Convenient patch and waveform storage.

CONS: Documentation could be more detailed.


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