FIG. 1: Deceptively designed to resemble a stompbox, the MF-102 gives you instant control over a number of useful modulation parameters.
For more than four decades, venerable and quirky ring modulators have been purveyors of blessed angularity to electronic, jazz, and pop music. Valued for their ability to transform ordinary source signals into wilder, inharmonic timbres, ring modulators were considered an essential part of the earliest electronic-music studios. Popularized in the 1960s and 1970s by jazz artists such as Don Ellis, they've shown up on numerous recordings, from early releases by Can to remixes of Brazilian artist Tom Ze. Voltage-controlled synthesizers featured them prominently, and manufacturers such as ARP, EMS, Moog, Oberheim, and Roland included them integrally or as an option.
Though stand-alone units are nothing new (PAIA continues to sell a ring-modulator kit that Craig Anderton popularized years ago), the Big Briar Moogerfooger MF-102 and DACS FREQue represent inventive twists that, respectively, refine the basic design and try to stretch its application. I'll look at each in succession and explore their sonic weirdness. But first, some quick basics for the uninitiated.
A ring modulator, or balanced amplitude modulator, is a circuit that modulates two separate input signals, the carrier (c) and the program (p), generating sideband frequencies at a single output. (Some implementations call the signals the carrier and the modulator. For this article, however, we're adopting the terms used by both manufacturers.) The catch is that neither of the input frequencies appears at the output. Rather, the sideband frequencies generated are the sum (c+p) and the difference (c-p) of the input frequencies. If we were to introduce two sine waves with respective frequencies of 500 Hz and 200 Hz, for example, the ring modulator would generate sine waves of 700 Hz and 300 Hz at the output. The input frequencies would be suppressed; they would not appear at the output. (In the past, poorly designed ring modulators often allowed the carrier to leak through, thus ruining the effect.)
Most ring modulators use AC coupling to get rid of any DC component in the incoming signal, thus balancing the signal. Also, ring is an old electronic-music term referring to how the circuit is configured around a diode ring. (For more on modulation synthesis, see "Square One: Modulation Synthesis Methods" in the March 1999 issue of EM.)
As many readers know from my review of the MF-101 Lowpass Filter in the June 1999 issue of EM, I'm a fan of the Filter's Minimoog knobs and overall style. The same goes for the MF-102. In fact, the two chassis share the same configuration of knobs and switches.
The controls on top are distinct and divided into two sections: a low-frequency oscillator (LFO) section on the left and the Modulator section on the right (see Fig. 1). Between them are a Drive knob and three LEDs that indicate the level of signal being driven, the rate of the LFO, and bypass state.
The Modulator section features a Mix knob that crossfades smoothly between a clean signal at the audio input and a fully modulated one when turned completely clockwise. A Frequency knob lets you adjust the pitch of the built-in carrier oscillator. The Frequency knob has two ranges, 0.5 Hz to 80 Hz and 30 Hz to 4 kHz. A blue Lo/Hi switch above the knob selects between the ranges.
The LFO section is a mirror of the Modulator half. The top knob controls the LFO amount, and the bottom controls the rate at which the LFO oscillates. The action of the LFO is to frequency-modulate the carrier oscillator-a cool addition that increases the range of modulation options. The amount of LFO oscillation covers a range of 0 to 3 octaves. A switch between the Amount and Rate knobs selects whether the LFO produces a square wave or sinelike wave. Square LFO waves will typically introduce trill effects, and sine waves give a vibrato character to the sound.
The back panel provides input and output on 11/44-inch unbalanced connectors; four expression-pedal inputs to control Rate, Amount, Mix, and Frequency; an external carrier input; and LFO and carrier outputs to control other analog synths or another Moogerfooger. There's also a wall-wart power-supply jack to feed juice into the unit.
FIG. 2: The MF-102 flowchart
The block diagram of the MF-102 shown in Figure 2 gives a good overview of the unit's layout. Note that the external carrier input defeats the signal path from the MF-102's built-in carrier oscillator. This means that the action of the LFO is limited to the internal carrier and won't influence external carrier signals you might plug in, such as a synth or a sampler. No big deal, but worth noticing.
In action, the MF-102 is lovely and warm sounding for a beast that can also warp your most cherished material. Using the internal triangle-wave carrier lightly modulated by the LFO sine wave, I dialed in sweet vibrato to kick back and strum my Strat through. But I also craved a crazed, mechanical weasel sound. So I spun the LFO section fully clockwise, switched it to a square wave, set the carrier frequency to 1 kHz, and cranked the Mix to 10. Bingo-a melody crusher, metallic and harsh. Sure, it's borderline behavior to savagely attack your pickups with an EBow and spend an hour twiddling knobs with your free hand or foot. But that's exactly what this box invites: anarchy with drool on its chin. You might as well run a DAT and record a piece.
What about bass guitars, you ask? If you want to approach the sound of an old gong, look no further. You'll want a sampler nearby, too. I found myself backing up numerous sounds and documenting their settings as I wrote this review.
My first experiments with the MF-102 started with a relatively uncomplex sound at the audio input-a droning, filtered triangle wave off a Minimoog-and tweaks to the internal carrier and LFO. Things got pretty wild when I defeated the internal carrier with a fast, eight-step loop off my old Oberheim's built-in sequencer. Combined with another half-speed loop at the audio input, the effect was wicked. Next, I fed the inputs some industrial sound effects, talk radio, and foreign-language fitness-instruction records. Eventually I lost sleep.
You can hit the MF-102 pretty hard before the distortion starts to bug you. The unit has a three-stage LED, illuminating from green to yellow to red. Around yellow, the sound had pleasant harmonic distortion, and occasionally pegging the red wasn't a problem. Also, I found no leaking through of either the carrier or audio input.
I used the Moogerfooger EP-1 expression pedals ($40) with the MF-102, and they worked well. Since they free up your hands, you should have at least one for studio or live work. However, when pressing down almost all the way, I did seem to have less range of control over the upper registers of the carrier frequency. My style was to use the MF-102 as a tabletop unit, but you'll find your favorite approach.
The manual is excellent. It's wonderfully brief, but detailed enough to teach you about the unit. It also includes a few sample settings to let you get a feel for all the features.
NEXT STOP, NEPTUNE
Okay, what do you do when one ring modulator is not enough? The folks at DACS in England figured they'd stack two of them together in their FREQue, a deliciously insane box. "Chaos through broken horn-rimmed glasses," a friend was inspired to say.
FREQue is the flagship of DACS's FwS series of ring modulators released in 1998. Designed by British engineer Douglas Doherty, the family of ring modulators ranges from the stripped-down Module8 ($735) and ColOscil ($875) to the tricked-out FREQue. With two ring modulators, two built-in oscillators, CV inputs, internal frequency modulation, and a frequency shifter, the FREQue provides an excellent hybrid instrument for the analog synthesist. It also sports a chassis built of heavy-duty plastic, making it very portable.
KNOBS ON ACID
You can't miss the front panel of the FREQue: it's an inescapable fractal soup of color with black knobs and red buttons jutting out. The exact purpose of this unit will initially elude most folks. This mystery factor is a smart ploy by DACS to make the unit stand out in a rack and to hint at its weirdness. The focus is on knobs, tempting the user to come hither and twiddle.
The back panel features the same swirling motif as the front. There is a CV input and oscillator output for each FREQue module, as well as independent carrier (Mod) and program (Music) inputs. Note that the two outputs (Out) are also labeled FS Down and FS Up. We'll cover that feature later.
FIG. 3: The FREQue front panel offers plenty of knobs for the tweakably inclined. Note that we've removed the front panel's psychedelic color in this illustration for clarity.
As you can see in Figure 3, the FREQue stacks two identical modules-ColOscil modules, to be precise-and includes some FREQue-specific features. At the far left are input-level meters labeled Mod and Music. The lower LED registers green for an input above -40 dB, and the upper shines yellow if you're around +2 dB. For better performance, DACS recommends staying between +2 dB to +12 dB at the input. However, there is no input-gain control. Depending on your source, you may need a decent preamp for your material. I had no complaints with introducing material slightly below +2 dB, but below 0 dB, the noise floor became an issue.
The cryptically labeled Weight and Edge knobs vary the spectral content at the output of the ring modulator. The two controls act on the music input, providing bass and treble filtering at 80 Hz and 8 kHz. A red button activates and deactivates the effect, but treatment is also bypassed when the knobs are centered. The effect is not as pronounced as you might imagine because it's entirely dependent on material at the Mod input. I tended to get a harsher quality with Edge boosted and more support on low end with Weight cranked.
The FREQue features two built-in sine/cosine wave oscillators as modulation sources. Activating them bypasses signals at the Modulator inputs. Each oscillator has broad and fine-tune controls as well as a four-range switch that selects among 0.1 Hz to 28.5 kHz, 5 Hz to 153 Hz, 30 Hz to 1.3 kHz, and 111 Hz to 16.5 kHz. You get desirable LFO frequencies for gating and tremolo effects, as well as a warm low end, with clean mid and high frequencies in the audible range. In the box that I used, the output of Osc 2 tended to be hotter than Osc 1, but I believe this was an anomaly in my unit.
FREQue includes a front-panel routing switch that disconnects Osc 1 and sends Osc 2 to the Mod inputs of the bottom module. This lovely feature allows Osc 2 to modulate both channels, which is useful for controlling stereo effects from one knob.
Next to the Osc 1 switch is a frequency modulation (FM) switch. When engaged, Osc 1 modulates the frequency of Osc 2. A knob to its right functions as a mix knob, increasing modulation as you turn it clockwise. In general, this setting tends to impart a grittier sound due to the increase in sidebands. A low setting can yield a vibrato or phasing effect.
The last router is the FREQue button, which engages Frequency Shift mode and deactivates the Osc 1 switch. This feature requires both Osc 1 and 2 to be activated and employs both outputs. The treatment shifts frequencies upward at FS Up and downward at FS Down by a fixed number of cycles per second. The degree of modulation is determined by Osc 2, which can be controlled internally or via CV. This makes a great subtle stereo treatment. The only downside is that my unit made an unpleasant click in the monitors when I pressed this button. (The manufacturer is currently addressing this problem.)
As with the MF-102, most of my test source sounds came from a Minimoog, radio, guitar, bass, an Oberheim 2-Voice, and lots of sampled oddities. I punished the FREQue with sound, and it responded well. Generally its quality was less warm and more metallic than the MF-102's, but more radical and unpredictable given the doubling up of modulators and increased routings. Also, having CV inputs to control both modulating oscillators was a smart design choice. Those of you who own MIDI-to-CV converters will be able to finely control both oscillators from your sequencer. This is useful for phrasing (and for freeing up your hands, too).
Items on my wish list include a Mix control to vary the intensity of modulation at the outputs, peak-level meters, and a footswitch. Also, the unit has no power switch, though turning it on from a power strip didn't bother me.
DACS includes a concise manual that reviews all the functions of the FREQue. The company's Web site mentions downloadable application examples, setups, and sound files, but as of this writing none were there. The company has published DACSData, a useful newsletter that includes tips on drum, delay, vocal, and multiple modulation. Perhaps they'll move that information onto the Web.
BACK TO EARTH
Both the MF-102 and the FREQue excel as signal processors, and I would be hard-pressed to choose one box over the other. More than just a throwback to earlier days, both units include enhancements that make them quieter and more flexible instruments than their predecessors. I've also listened to lots of ring-modulator algorithms on synthesizers and computer workstations, and these boxes blow the digital versions out of the studio.
Although the $299 MF-102 costs a mere fraction of the $1,099 FREQue, the latter features two ring modulators with a larger set of modulation features and possibilities for stereo manipulation. Besides the cost factor, the main issues really are the interface and the character of the sound you get. The MF-102 has well-marked, clearly readable controls on a portable chassis. It's a high-class stompbox for guitarists and makes a great addition to any electronic-music studio. The FREQue is just that: a psychedelically clad anomaly that makes sounds which defy description. Markings are scant, however, so you might get a little irritated with the free-form approach that the designer has imposed on you. But you'll probably be the only kid on your block to own one.
If what you want is a warmer sound, you might lean in the direction of the MF-102. If you're looking for more edge, try out the FREQue. My vote is to let your budget point the way. You won't be disappointed with either choice.