When Yamaha introduced the DX7 in 1983, its crisp, detailed, and sometimes clangorous timbres provided stark relief to the cloudy, warm tones of analog synths. The DX7 and its ensuing frequency-modulation (FM) synthesis counterparts had a few drawbacks, however; compared with the capabilities of analog synthesizers, real-time control was minimal. The DX7 couldn't even come close to delivering the timbral warmth and thickness typical of analog synthesizers. By the time I sold my DX7 in the late '80s, the demand for FM synthesis was largely overshadowed by the clean, detailed timbres of sample-playback synthesizers.
During the past decade, that appears to have come full circle. Real-time control is again part of the musical toolbox. Analog synths (authentic and modeled) are again in favor in the electronic-music marketplace. Still, Yamaha has continued to champion FM synthesizers with a new wrinkle here and a new feature there.
Enter Yamaha's DX200, a groove box that derives its sounds from an FM synthesizer and a sample-playback engine. Don't be fooled into associating the unit with your old FM sound cards or even your antiquated DX7; the DX200 is a synth of a different stripe. In the DX200, the once cold, brittle sounds of FM synthesis have undergone a truly impressive transformation.
The DX200's work surface is divided into several functions, many of which overlap (see Fig. 1). The Control section in the lower left corner contains transport controls and buttons to enable the keyboard, shift octaves, tap in tempo, add swing, and perform additional chores. The Shift button accesses secondary functions, which are stenciled in raised letters below the buttons or indicated by a slash next to a knob's main function. Hold the Shift button and turn the filter's Cutoff knob to select a different filter type, for instance.
Directly above the Control section, nine backlit indicators that denote the mode in which you're working accompany a four-character LED display. The Store button saves your edited Voices, Patterns, and Songs. The Show Value button interacts with the synth voicing section by “freezing” your most recently edited synth parameter values.
The DX200 offers many thoughtful programming conveniences. If tweaking has taken you far astray of where you started, hold the Shift and the Show Value buttons simultaneously to display a parameter's original value. The Exit button unfreezes the synth parameter controls, and the Data knob changes values in conjunction with other controls.
To the right of the DX200's Control section is a 16-button keypad that serves as a single-octave keyboard for entering notes. Keys 1, 4, 8, and 10 don't transmit notes, which can be somewhat confusing in the midst of pecking out a pattern, but fortunately, the active keys light up. The Shift key engages the bottom row of keys in various Pattern- and Song-editing functions.
The Voice section dedicates 16 knobs and 16 buttons to controlling various sound parameters. Voice-editing capabilities make the DX200 really shine, so perhaps it's best to take a take a closer look at the synthesis functions before I describe the controls in greater detail.
Yamaha based the DX200's FM sound engine on the same 16-note polyphonic, 6-operator synthesis as the DX7. The DX200 arranges its FM Operators into the same 32 algorithms as its predecessor, and using System Exclusive (SysEx) messages, you can access the DX7's voicing parameters.
Overlaid on the FM synth is a host of subtractive-synthesis features that most significantly provide a powerful multimode filter. Its responses range from 24, 18, and 12 dB lowpass to bandpass, highpass, and band eliminate (see Fig.2). All filter types are resonant, and the 24 dB model can be driven into whistling self-oscillation.
In addition to the six envelope generators (EGs) provided by the FM operators, the DX200 has ADSR envelopes for the filter and amplifier sections. An LFO (again, in addition to the one embedded in the FM engine) provides a choice of triangle, sawtooth (up and down), square, and sample-and-hold waveforms. You can assign the LFO to modulate amplitude, filter frequency, or pitch.
The DX200's sample-playback engine offers 32 notes of polyphony. Instead of multiprogram Performances, the DX200 provides a single keymap that consists of three bass sounds occupying the greater part of the bottom three octaves and an assortment of drums and other sounds from MIDI Note Number 36 through 120. Unfortunately, each bass extends only 11 semitones before the next sound kicks in; that is definitely not the sound set for Jaco Pastorius devotees. The drum sounds run the gamut from synthetic snares, kicks, and hats to processed- and natural-sounding acoustic drums and cymbals to udu and tabla variations. Higher on the keymap are thwacks, claps, smacks, and chordal instrument hits; some sound natural, and others, blatantly synthetic.
The drum and bass sounds are gated by the DX200's keypads or through MIDI. The inability to mute one sound with another (such as a closed hi-hat muting an open one) is doubly unfortunate, because you can't easily create realistic hi-hat parts. Cymbals cut short immediately after you release their triggers, making realistic cymbal parts difficult, if not impossible, to achieve.
In the Noise Oscillator section, a button lets you select from five noise types. You can sweep the noise source's filter frequency, but that's about it. Although the Noise Oscillator doesn't interact with the FM tone generators, FM synthesis can generate plenty of interesting noise on its own.
IN REAL TIME
All of the DX200's 18 knobs (except the Main Volume knob) send MIDI Control Change (CC) messages. The Data knob sends messages based on its context. For example, when you hit the Pattern Select button, the Data knob sends Bank Select and Program Change commands. If you twirl the filter's Cutoff knob, the Data knob duplicates its function but with finer resolution. Both the Data knob and any parameter knob send a CC message beginning with the parameter's current value, preserving smooth timbral changes by preventing the unit from sending discontiguous values. Because the Data knob offers finer resolution, it sends data more fluidly than a parameter knob, which can achieve a stair-stepped effect if that's your goal.
The DX200's control surface provides a tremendous complement of real-time voicing capabilities. Four knobs, one each for Attack, Decay, Sustain, and Release, afford hands-on control of amplitude and timbre changes over time, with a button to switch between amplitude and filter envelopes. I would prefer four knobs for the filter envelope and four more for the amplifier envelope, but considering the small footprint of the box and the number of controls, a toggle button is a reasonable design compromise.
The filter section sports three knobs for cutoff, resonance, and envelope depth. By adjusting cutoff and resonance settings, I was able to make the filter oscillate. When I applied the EG to modulate the filter, I created a melody that followed the pitches in a Pattern I was playing.
With the Shift key, the Cutoff knob selects among filter types. You can invert the filter's envelope with the Filter Envelope Generator (FEG) Depth knob — a nice touch. Depending on cutoff and resonance values, settings at either extreme of the envelope depth can overdrive the filter, creating short bursts of howling feedback that sound great.
The DX200's effects section is rather spartan, but that's a minor quibble, considering the unit's price. Chorus and reverb supplement a modest assortment of delays, flangers, phasers, and amp simulators. Sparse though they may be, you can sync time-based effects to a song's tempo or MIDI Clock. For the delays, flangers, and phasers, the Parameter knob controls rate, and for overdrive, it controls distortion depth. The effects processor doesn't provide multi-effects, so you can choose only one effect at a time. The selected effect applies to FM and sample-playback tones alike.
ON THE FM DIAL
The transformations that occur when you can apply real-time controls to an FM synth are a revelation; the DX200's Harmonic and FM Depth knobs are especially effective. The Harmonic knob changes the waveform by continuously varying the frequency of the FM modulators. For example, I selected a rich sawtooth pad and adjusted the Harmonic knob to smoothly change the sound from a muted, brassy character to a bright and bell-like timbre rich with inharmonic overtones.
The FM Depth knob controls the amplitude of the modulators, which allowed me to change a bland sine wave to a harsh, metallic, distorted timbre with overtones that an analog synth could never produce. Using the second Decay knob, which controls only the FM modulators, you can vary the sound from sustained tones with overlapping tails to short, clicking tones. Like the filter envelope, you can invert the modulation values of the Harmonic, FM Depth, and Decay knobs.
Judicious use of the Modulator button paints your sounds with a finer brush by controlling all the modulators or any one of three. By choosing a single modulator, you can make subtle changes to a single element using the Harmonic and FM Depth knobs. A 6-operator FM patch can contain more than three modulators, but given the wealth of timbral modifiers versus the available surface area, I can accept a few design compromises; I don't want to be greedy.
The Algorithm Type button toggles through all 32 FM algorithms on the fly, drastically altering timbre. Repeated button presses call up the next algorithm in line, from high to low, and then loop back to your initial selection. Pressing the button rhythmically gives the sound a Korg Wavestation — like motion. To scroll through a limited range of algorithms, you can use the Data knob, but for creating rhythmic effects, a button works better. I was disheartened to discover that I could not record algorithm changes into the DX200's sequencer, but I easily obtained the effect I wanted by recording to my computer's sequencer.
Most of the DX200's sequencer controls are simple and mainstream. As with most pattern-based sequencers (and most drum machines), you create Patterns and link them together into a Song. Patterns are limited to single measures of 8, 12, or 16 steps.
The DX200's song-assembly style leaves much to be desired; constructing music one measure at a time is counterintuitive. Even modern hardware sequencers let you assemble parts of a composition from start to finish without the need to link patterns. Furthermore, the keyboard sends a fixed Velocity message, which you can adjust only by pressing and holding a combination of buttons. Nonetheless, the DX200's sequencer offers a bunch of cool tricks all its own, including a continuously variable Swing function and a button that instantly reverses the pattern.
The sequencer's star feature, however, is the Free EG section. Free EG captures and plays back knob and switch moves, thereby re-creating whatever motion you impart to the synth in real time. The DX200 has four Free EGs, and their lengths can be set to overlap Patterns. Free EGs can be triggered when you press the Play button, send a MIDI Start message, or send a Note On. Note On triggering animates the DX200's sound, even if you use it as a passive sound module.
Free EG can capture most knob and switch movements, but I was disappointed to find a few movements it doesn't record. I was delighted when I started playing rhythm patterns as I tuned the filter cutoff for a wah-wah effect, but when I tried to overdub my filter tweaks, I quickly discovered that the filter section is disabled when you record the sampled parts. Similarly, Algorithm Type selection is disabled when you record FM synth patterns. The Cutoff knob and the Algorithm Type button send MIDI CCs, so you can record them into an external sequencer, but I'm disappointed that the internal sequencer lacks that capability.
The DX200 also lacks a Pitch Bend control. You can certainly send Pitch Bend from an external source, but because the DX200 is so self-contained, I'm surprised that that basic feature was not assigned to a knob.
Perhaps the strangest limitation is that the sequencer track that records FM sounds is monophonic. Adding a multitimbral FM section would probably have increased the unit's cost, but I can't understand why a 16-note polyphonic synth should be hobbled by a monophonic sequencer part.
The manual is well written and includes 93 detailed tips for using the DX200. If you're new to FM synthesis, the appendix gives you a good, nontechnical introduction to the underlying concepts.
Yamaha bundles a DX200 Editor program for Windows and the Mac OS that allows you to edit and store sound parameters and sequences. You can construct an entire song on your computer and then dump the data to the DX200. The software provides a sequencer section that resembles an analog-style sequencer, with virtual knobs for setting the pitch of each step (see Fig. 3). You can even draw parameter changes into a window that displays the Free EG.
With DX200 Editor's Voice-editing facilities, you can graphically get down to the FM nitty-gritty and then polish your FM sounds with subtractive synthesis parameters. The Voice-editing section features a few parameters that aren't accessible from the hardware, including a 2-band EQ.
A DX7 Simulator window displays a virtual DX7 keyboard for triggering sounds and editing Voices. The simulation is comprehensive, down to its virtual membrane switches and function buttons. Clicking on any button reveals a close-up of the Edit window. Although the simulator lets you edit FM Voices as though it were a DX7, why would anyone want to? Thanks, but I've done that already.
IS IT GROOVY?
The DX200 is a blast to play. The synergy of FM synthesis and subtractive synthesis coupled with real-time control is fresh and powerful. Because the DX200 is compatible with DX7 SysEx, an enormous collection of ready-made sounds is available, and each Voice can seed tons of variations.
I'm not too enthusiastic about the sequencer section, which is a curious mixture of real-time flash and unwieldy button presses. I'd rather sequence a song from beginning to end than arrange single-measure patterns into song form. The sequencer's lack of polyphonic FM playback is a drag, and the keypads aren't Velocity-sensitive. I'm disappointed at the omission of certain real-time recording features, such as changing algorithms on the fly. Devotees of analog-style step sequencing might find a lot to like, but I don't.
On the other hand, strictly as a sound module, the DX200 works well. Clearly, the DX200's designers strove to present an analog, subtractive surface on the DX200, but that's only the tip of the tonal iceberg. The DX200 is quite capable of creating effective analog-type sounds. The fat, resonant filters impart a warm quality to the typically brittle sound of digital FM. The DX200's synthesis capabilities far outweigh its utility as a groove box. Give it a thorough listen and spin some knobs.
Assistant editorMarty Cutleris known for his “outside” approach to bluegrass banjo: his parents always told him to play there.
FM groove box
FEATURES4.5EASE OF USE4.0SOUND QUALITY4.0VALUE4.0
RATING PRODUCTS FROM 1 TO 5
PROS: Real-time FM control. Subtractive synthesis capabilities provide warmth and depth. Free EG feature automates parameter changes. Well-written manual.
CONS: Sequenced FM synth playback is only monophonic. Free EG can't record some FM synth parameters. Rhythm tracks don't record filter tweaks. No onboard Pitch Bend.
Synthesis6-operator digital FM; sample playbackMaximum Polyphony16-note (FM); 32-note (sample playback)Multitimbral Parts1 (FM); 3 (sample playback)Effectsdelay, reverb, chorus, flange, phase, overdrive, 2-band EQSequencer16-step, analog style with Free EG to capture CCsAnalog Outputs(2) unbalanced ¼"; (1) ¼" stereo headphoneMIDI PortsIn; OutDisplay4-character, 7-segment LEDDimensions13.50" (L) × 2.20" (H) × 8.25" (D)Weight3.5 lb.