Moogerfooger pedal with unique analog synthesis capabilities.
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Web Clips: Listen to audio examples of pitch change, hard sync off, and more from the Moog Music MF-107 FreqBox effects processor

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The Moog MF-107 FreqBox brings unique analog synthesis capabilities to your guitar pedalboard or effects arsenal.

Over the past few months, pictures showing Red Hot Chili Peppers guitarist John Frusciante's pedalboard have made the rounds online and in print. The photos confirm that he's a fan of Moog Music's boutique stompbox effects, with no fewer than six Moogerfooger pedals in his rig. Moog has capitalized on the resulting swell of interest in Moogerfoogers with the release of the MF-107 FreqBox ($359).

The FreqBox is an analog synth module in a box, with an input that accepts audio signals from instruments and line-level sources. The device looks like a large effects pedal, but it works in a fashion unfamiliar to most guitarists. Instead of simply processing the input signal, it routes the signal to modulate an internal voltage-controlled oscillator (VCO), essentially replacing sounds from your guitar or other source with FreqBox tones.

Inside Job

Depending on the mode of operation you choose, the FreqBox uses the input signal as the master waveform for hard sync, the modulator for FM synthesis, or the source for an envelope follower that alters the VCO's pitch in response to your playing dynamics (see Web Clip 1). The Env Amount and FM Amount knobs on the unit's right-hand side determine the degree to which the FreqBox uses each mode. Knobs on the left determine VCO characteristics such as waveform shape and frequency. You can toggle hard sync with a switch, and there are additional controls for level and drive as well as a bypass footswitch.

The FreqBox's all-analog design has two major implications. First, it's easy to add control voltage inputs, because no A/D conversion is necessary to plug an external device into the circuit. Indeed, the back of the unit is festooned with ¼-inch TRS jacks that let you control almost all the front-panel functions with expression pedals or other gizmos. The only glaring omission is a footswitch input for toggling sync mode.

Second, and more problematically, being all analog rules out presets, which would require A/D conversion of the control signals and the dreaded quantization of parameters. That makes the FreqBox a bit of a one-trick pony for live applications if it's sitting on the floor — that is, unless you connect expression pedals for real-time control, and you can connect as many as five. And it does balance quite nicely on the edge of a keyboard, as long as you have enough extra space next to your modulation wheel.


If you're in a situation that allows for twiddling, the FreqBox is a pretty potent device. Aside from the lack of stereo input, it is quite well suited to the studio; Moog even sells a three-Fooger rackmount kit ($59). A quick survey of the user forums turns up intrepid adventurers stringing them up alongside the CP-251 control voltage generator ($369) to create quasimodular beasts (see the CP-251 review at

The hard-sync modes are by far the most useful, because they're the only way to match the output pitch to the input; with sync turned off, the frequency knob or CV input determines pitch. The FreqBox can be interesting even with sync turned off, though. Carefully tuning the VCO frequency for a harmonically simple song can continually emphasize an important note (see Web Clip 2), and driving the pitch with an expression pedal inevitably leads to dramatic Tom-Morello-like whammy freak-outs (see Web Clip 3).

When you aren't using the Frequency knob to modulate pitch, you use it to change the filter cutoff, switching between the Moog equivalents of whammy and wah as the sync mode changes. It's possible to mangle your sounds pretty aggressively (see Web Clip 4), but with a sufficiently subtle setting on the Mix knob, you can blend in even the most outlandish configuration as an agreeable sonic backdrop.

Freq Out

For anyone on a musician's budget, the FreqBox isn't inexpensive enough to be an impulse buy, and it definitely exists outside the normal realm of most guitar effects users. Given that diminutive sub-$200 DSP boxes with nowhere near the FreqBox's level of ingenuity dominate the market, though, it's hard to quibble about any of its quirks.

With a bevy of expression pedals and a quick right foot, you can use the FreqBox to deliver an infinite variety of sounds — literally, because the values aren't quantized — that you just can't find elsewhere. It isn't for everybody, but if you do use one, you certainly won't sound like anybody else.

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Moog Music

Web Clips: Listen to audio examples of pitch change, hard sync off, and more from the Moog Music MF-107 FreqBox effects processor