Korg Monotron Quick Pick Review

It''s a welcome surprise to see Korg, one of the original names in the synth biz, enter the analog-hardware renaissance with the Monotron ($59.99).
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The Monotron includes a power/LFO-mode switch, five knobs, a ribbon-strip keyboard, and a 1-inch speaker with a volume control on the back panel.

It''s a welcome surprise to see Korg, one of the original names in the synth biz, enter the analog-hardware renaissance with the Monotron ($59.99). This pocket-sized, self-contained instrument has a built-in speaker, runs on two AAA batteries, and is perfect for portable play, as well as introducing kids to the joys of electronic music. But don''t let its size and price fool you: The Monotron has a sound that pros will enjoy.

The Monotron is reminiscent of early single-oscillator monosynths such as the Korg MS-10 and the Moog Micromoog. In this case, the synth voice features a sawtooth oscillator going through a resonant 2-pole lowpass filter (based on the company''s classic MS Series instruments), with a sawtooth LFO for modulating pitch or the filter''s cutoff frequency.

Only slightly bigger than an iPhone, the Monotron is remarkably simple to use. The interface includes a switch, five knobs, a ribbon strip, and a back-panel volume wheel (like you''d find on a transistor radio).

The ribbon strip has an octave and a third of piano keys printed on it, and provides the gate and pitch sources. You can play the ribbon keyboard with a finger or, for greater accuracy, a plastic stylus from a portable game. With the Monotron placed on a grand piano''s music stand, I was able to play pitch-accurate melodies with my right hand while comping chords on the piano with my left hand.

The power switch, labeled Standby in the off position, is also used to select whether the LFO modulates VCO pitch or filter cutoff. The master Pitch control gives you about seven octaves of usable range, with a rear-panel control for adjusting the keyboard''s range. There are separate controls for the LFO speed and depth/intensity. The LFO speed ranges from one cycle about every 12 seconds to well into audio range, and the control knob flashes in time with the LFO rate.

The VCF has controls for the cutoff frequency and resonance (labeled Peak). The filter goes into resonance easily, and the resulting pitch gets into the whistle registers when you have maximum frequency modulation dialed in.

In addition to the stereo 3.5mm headphone jack, the Monotron has a stereo 3.5mm aux input to run audio from external devices through the Monotron''s filter. Plugging into the input jack disables the gate, so you don''t have to play the ribbon strip to hear an external sound go through the filter—a nice touch.

To process external audio using the LFO, switch to Cutoff Mod mode and then adjust the input signal''s volume so there''s no unwanted distortion. Begin with the Intensity and Peak controls dialed down (fully counterclockwise), and Cutoff wide open (fully clockwise). The Monotron''s filter resonance can get pretty hairy, producing a satisfying palette of sidebands when the LFO is running at audio rate. But you can get a nice woody tone from the filter when it''s partially closed.

Pitch the filter resonance down using the Cutoff control and pulse it with the LFO to create a four-on-the-floor bass drum beat (see Web Clip 1). If you want it to repeat without having to play the ribbon keyboard, simply plug one end of a stereo cable into the input jack to open the gate.

Synth geeks will notice a lack of control over the Monotron''s envelopes, and there are no pitchbend or mod wheels, no MIDI I/O, and no effects or patch memory, and you cannot change the core waveforms. Oddly enough, I didn''t miss any of these features, and including them would most certainly have increased the size and cost of the unit.

Yet, like nearly every analog device, the Monotron has its quirks. The main issue I have is that the line output is somewhat noisy. In addition, some sounds overload the built-in speaker, causing the synth''s case to buzz. Fortunately, it does this in ways that are musical. It''s easy to overdrive the entire instrument—crank the volume to the top, put the filter into resonance, modulate the VCO at audio rate, and then dial in a pitch that makes the plastic case rattle. (When it first happened, I thought I had discovered another modulation parameter. Well, I had—the speaker and case.)

And because the speaker is about an inch in diameter, you can aim it into your mouth to simulate formant filtering and talk-box effects (see Web Clip 2). You''ll need a mic to record the results.

It would be easy to view the Monotron as a 21st-century Stylophone—a one-trick pony. But despite its toy-like appearance, the Monotron is a remarkably sophisticated synth, capable of creating some very rich tones. It is also the least-expensive stereo analog filter (with a built-in modulator) that you can buy, and the filter has a lot of character.

The Monotron is small, inexpensive, and fun to play. Best of all, it sounds great and is easily the smartest synth and filter purchase you''ll make this year.

Overall Rating (1 through 5): 5
Korg Monotron Product Page