Big Briar MF-102/DACS FREQue

Nov 1, 1999 12:00 PM, By Alex Artaud

UNLEASH A RIOT OF SONIC CUBISM

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.)

MOOGULATED MUZIK

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.

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.

STOMPING IN

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.