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The Incredible Realism of the Moog Multimode Filter

If UA were able to conceive a Moog product, what would it be? The answer is revealed in the Moog Multimode Filter, which delivers the first truly analog-sounding VCF (Voltage Controlled Filter) digital emulation made for mixing, performing, creating, or destroying. How can we claim this? The devil is in the details … read on-and then listen! Created in conjunction with the foremost pioneers in synthesis, the Moog Multimode Filter is a virtual tabletop filter set that combines the best of Bob Moog’s classic designs with select features from his final Voyager instrument. It is an amalgam of the best new and classic Moog designs, with a few innovations thrown in!

Go Ahead, Judge a Book by its Cover

I have to say, I think the Moog Multimode Filter’s GUI is beautiful. And it wouldn’t be a mistake to assume it sounds as good as it looks-in this case it really does. But where did this design come from? This really represents a dream product for Universal Audio: A chance for the guys at UA to become Moog designers for a period of time. We literally asked ourselves, "What product would we want Moog to make that was somewhere between the MF products and a full-blown instrument?" A tabletop filter set is what we really wanted to see: A little more feature-rich than Moogerfooger, but without the oscillators and keyboard, and something that the masses could afford. Cosmetically, it should be a combination of the Moogerfooger’s stomp-box toughness and the elegant panel backlighting and color scheme of the Voyager, of course with the trademark wood sides. If this exact box was available in the analog domain, I'd buy it in an instant!

UAD Moog Multimode Filter screenshot
UA and Moog bring the DAW dream machine to filter freaks: The Moog Multimode Filter

First, Let’s Drive

The signal path begins with the critical distortion qualities of the Moog lineage. As one would expect, the input’s Drive control allows the user creatively to distort the incoming signal. A broad 40dB range offers a wide array of distortion characteristics, mild to mean. However, for the extremist, the Moog Multimode Filter incorporates a 0/+20dB gain switch, giving an option for the extreme distortion capabilities found at the Minimoog’s external input. The sound of this switch is not for the faint of heart--the external input on the Minimoog provides some SERIOUS distortion, and the Moog Multimode matches the distortion qualities and levels of the original very accurately. On a side note, the SE version of this plug may be just the ticket for the "distortion-free" filter camp, of which I know there is a large contingency. The primary difference between the full and SE (besides the obvious DSP savings) version is that the latter is totally devoid of distortion qualities. So the SE may be preferable for some filter freaks!

Next, Filter …

UA modeled the analog behavior of the historic 4-pole ladder filter conceived by the world’s most recognizable electronic-instrument maker, right down to the self-oscillation and nonlinearities of its analog counterpart. As the name suggests, the heart of the Moog Multimode Filter is the switchable lowpass, highpass, and bandpass filter which allows Moog’s signature self-oscillation and extreme resonance in any of the three modes, bringing a new level of sophistication to Moog filter designs of the past. How is this something different or new? Typically, the self-oscillation made famous by Moog is only found in the lowpass filter. Universal Audio has achieved a circuit design that allows the highpass (and bandpass) to oscillate to the same degree of beautiful ferocity. And this is not "digital-only" magic-this design is provable in the analog domain as well!

"This really represents a dream product for Universal Audio: A chance for the guys at UA to become Moog designers for a period of time."

Beyond this welcome enhancement, the Moog Multimode gives the sonic and tactile experience one would expect from a real analog circuit-the same beautiful "liquid" quality of the Cuttoff, the same chatter to the resonance that occurs on heavily driven transient-rich material. Add in the amazingly accurate model of the Moogerfooger MF-101 Envelope controls and you have a recipe for pure analog follower satisfaction, with all kinds of beautifully unpredictable sonic results depending on the source material and settings. To up the ante, we decided to enhance the creative license of our users by adding a negative value range to the Envelope parameter!

A truly digital-only feature also found in the Filter section is the Step/Track switch, which allows the user to bypass Cutoff “tracking” (AKA smoothing) in cases where extreme automation moves might make a stepped (non-smoothed) response more desirable; of course, users are free to use this control in other creative ways, too.

Then, Modulate …

How should we mangle the signal next? The LFO section of our little dream filter set incorporates the basics of what a user should expect from a Moog modulator: Rate, Amount, and a Wave table. The Moog Multimode offers all the classics: Sine, Triangle, up and down Sawtooth, Square and Random. Another digital-only enhancement is manifested in the choice between Free and Sync, which is our UAD Tempo Sync feature--still somewhat new for the UAD platform. When synchronized, the red LCD displays musical note values in the same way the RE-201 Space Echo plug-in does. Do you want to set the LFO rate so that it is the same each session? Click on the LFO meter LED-it is a “hidden” (and automate-able) control that allows the user to reset the LFO wave. Feel free to use it in any other creative manner too!

Now, Stereo!

Borrowing from the Moog Voyager, the Moog Multimode Filter is really two filters running simultaneously--with ganged controls for most everything. Like with the Voyager, the Spacing and Offset controls allow you to shift tonality between the filters. Spacing “spaces” the cutoff point between two separate, hard-panned filters by up to three octaves. This is an amazing feature that creates subtle beating between the filters at its most conservative settings, or goes all the way to wide stereo image/tonal shifting. Positive and negative values are available, which allows the user to reverse the image of the higher- and lower-pitched filters. Offset is found in the LFO section of our tool, which creates a phase difference between the two LFO-affected filters by up to -180º/+180º. This Rate- and Amount-dependent control can create that slightly disorienting, out-of-phase feeling--or dramatically increase stereo width, or even function as an audible delay effect. Again, reversing the stereo image is easy with the Offset negative value range.

UAD Moog Multimode Filter SE screenshot
The SE version of the Moog Multmode Filter is a distortion-free version with no Drive capabilities

Mix Options and the SE

Mix blends wet and dry signal, while Output controls the final volume of the instrument. In addition, a Mono/Stereo switch enables the mono summing of any stereo effect, plus Effect/Bypass turns off all effects but leaves the Drive and Output controls enabled. As mentioned earlier, we also offer the SE low-DSP version. Cosmetically, the unit uses the Luna backlighting and maplewood sides available from the Voyager Select Series (you owe it to yourself to check out Moog’s custom Voyager shop) to differentiate it from the electric blue/mahogany (!) full version. The two versions are functionally identical, except the SE version removes the 0/+20dB switch and Drive is renamed “Gain” for better technical accuracy under the SE. Again, this is because no distortion capabilities are included in the SE. Despite this, the user can freely copy/paste and save/load presets between the two versions with the upcoming 5.0 feature enhancements! Yes, it is true-UAD v5.0 adds the ability to copy and paste settings and presets between full and SE versions of the same plug-in. (Among many other great surprises!)

— Will Shanks

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