Twelve Under a Hundred

From time to time, EM's editors search out cost-effective solutions for common problems. Most electronic musicians use software instruments to one extent
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From time to time, EM's editors search out cost-effective solutions for common problems. Most electronic musicians use software instruments to one extent or another, and most are on a budget. So we decided to see what's available in low-cost virtual instruments.

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FIG. 1: You use Vocal''s formant-filter editor to construct two sets of five formants.

A quick trip to KVR Audio, the Synth Zone, Harmony Central, or the “What's New” and “Download of the Month” departments in back issues of EM reveals a huge number of software instruments. Prices range from free to stratospheric, and all platforms and formats are well represented. For this roundup, we decided to stick with synthesizers (no sample-based instruments) and limit the price to less than $100. Even at that, the field is huge, and we make no claim to having tried them all or picked only the best. Our goal was to present an interesting and varied collection of instruments, and that proved to be no problem. But many of the inexpensive soft synths we didn't cover are equally worthy.

The Field

Four of these virtual instruments are cross-platform, running under both Mac OS X and Windows. Seven of the remaining eight are Windows only and one is Mac only. That totals 11 Windows and 5 Mac synths. All of the Windows synths support the Steinberg VSTi plug-in format, and KV331 Audio SynthMaster also supports RTAS. All of the Mac instruments support the Apple AU format, and all but U-he Zoyd also support VSTi. SynthMaster also runs as a standalone application.

The synths run the gamut from commercial products with large preset libraries and complete manuals to experimental instruments that require some ingenuity to take full advantage of their features. Many come with little or no documentation, but you'll always find some presets and at least a few helpful hints to get you going.

Various synthesis methods are represented. Subtractive synthesis (sound generators followed by filters) is at the heart of the vast majority of software and hardware synths, and that's also true here. In fact, every synth covered uses filtering at some point in the signal path. LinPlug Alpha 3 and ReFX Vanguard adhere closely to the classic analog subtractive model, although each has features not found on classic synths. Green Oak Crystal, KV331 Audio SynthMaster, and U-he Zoyd are hybrid synths, featuring other methods along with subtractive synthesis. They are also semimodular, meaning you can rearrange their signal paths. Sonic Charge MicroTonic is a drum machine that uses subtractive synthesis for its sounds.

Six of these synths deviate significantly from the subtractive model. Nusofting Modelonia uses physical modeling of plucked-string and blown-bore instruments to generate its sounds. ConcreteFX Vocal combines oscillators with formant filters to create vocal-like sounds. Humanoid Sound Systems Scanned Synth VST uses a relatively new method called scanned synthesis. Mutagene Pocas and Progress Audio Soup are additive synths; Pocas adds a technique it calls chaotic particle modulation, and Soup adds vectored patch morphing. Rick Jelliffe's Neumixturtrautonium employs subharmonic synthesis.


Vocal ($46, Win, VSTi)
Although Vocal is designed to produce vocal sounds, its architecture and modulation routings give it a much broader reach. Vocal's signal path starts with two 3-oscillator sound sources; the oscillators play the same waveform, but you can tune them individually in semitones. You get standard synthesizer waveforms, noise, and two user-definable additive waveforms.

Each oscillator feeds its own 5-band formant filter, and the formant filters together with a separate noise generator feed a resonant multimode filter followed by an effects block. The multimode filter has 12 and 24 dB lowpass, bandpass, highpass, and band-reject modes. The effects block consists of chorus, phaser, stereo delay, and stereo spread in series along with tremolo and vibrato modulators.

The formant filters are the heart of this synth. Each of the six formant-filter presets — Standard, Bass, Tenor, Ctenor, Soprano, and Alto A — consists of separate 5-band configurations for the vowels A, E, I, O, and U. A slider morphs between the vowels for the chosen filter preset, and you can modulate, automate, and remotely control (by means of MIDI) the slider. Two user configurations, which are saved with the preset, can be drawn from scratch or created by modifying one of the factory configurations (see Fig. 1).

For modulation, Vocal has six AHDSFR envelopes, six LFOs, and six step sequencers. You use a modulation matrix to route any of those sources to oscillator and formant-filter parameters. The step sequencers hold from 1 to 16 steps and can run at rates ranging from ¼ to 4 times the host tempo. You can shape the transition between steps from instant to linear to convex-curved. The latter shapes are more useful for formant modulation.

If you're thinking Vocal is only good for vocal sounds, a spin through its six factory preset banks will disabuse you of that notion. This synth is great for pulsing ambient pads, honking leads, and resonant basses. The presets also illustrate a wide range of vocal effects (see Web Clip 1). Check out the free demo to see what Vocal has to offer.

Green Oak

Crystal (free, Mac/Win, VSTi/AU)
In soft-synth terms, Crystal is a bit long in the tooth, and the pace of updates has slowed recently. But it is actively supported, and up against the new, new thing, it still sounds great. Furthermore, most of the bugs are out, and a significant preset library has evolved over the years.

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FIG. 2: Crystal has six breakpoint envelope generators, six LFOs, and a 12-row modulation matrix to set things in motion.

Crystal layers three identical synths (called voices), each of which you can disable to save CPU cycles (see Fig. 2). Each voice consists of an oscillator and filter, with breakpoint envelopes for filter cutoff frequency and amplitude. The oscillators play standard single-cycle waveforms, multicycle sampled waveforms, and SoundFonts. You can also implement rudimentary forms of FM, ring modulation, hard sync, and granular processing. The oscillators feed resonant multimode filters, a saturation processor, and a waveshaper.

Crystal's mixer is one of its most powerful and unusual features. It incorporates a 4-way crossover and four feedback delay lines. Each voice has sliders for the amount sent to the crossover, each delay line, and the final output. You can use those to set up complex multitap delays, and the delay lines are capable of very short delay times for chorus, flange, and phase effects.

Modulation is another area where Crystal shines. In addition to the dedicated filter and amplitude envelopes, you can route six general-purpose envelopes to virtually any voice or mixer parameter. Each envelope can have as many as nine breakpoints, and each segment comes in a variety of shapes such as curved, pulsed, and spiked. A 12-row modulation matrix routes both the envelopes and six multiwave LFOs.

Programming Crystal is a little daunting, but three autoprogramming features circumvent much of the hard labor. As with many synths, you can randomize all settings, and with Crystal, that produces good-sounding results much of the time. You can also breed new presets that combine settings from two selected presets, which gives you a little more control. Finally, you can assign a modulator or MIDI controller to morph between two presets in real time. The breeding and morphing features, combined with a large collection of factory presets, mean you won't run out of fresh sounds anytime soon (see Web Clip 2).

Humanoid Sound Systems

Scanned Synth VST (free, Win, VSTi)
Scanned synthesis is the conception of Bill Verblank, Rob Shaw, and Max Matthews. You can think of it as a type of dynamic wavetable synthesis in which the performer manipulates the shape of a physical object (shaking a thin metal sheet, for example) while a closed path (say, a circle on the surface of the sheet) is scanned at audio rates. Changes in the shape of the physical object determine the shape of the scanned waveform, and the scanning rate determines the pitch at which that wave is played back. Because the shape is constantly changing, the scanned waveshape and timbre constantly change, but those changes are independent of pitch.

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FIG. 3: Scanned Synth VST offers controls for all elements of its string-scanning model.

Scanned synthesis has been realized both physically and with the aid of music programming languages like Csound. Scanned Synth VST is one of the first attempts to bring scanned synthesis to the desktop. The current version is free. A $99 version with an expanded feature set is planned for the future.

The original mathematics for scanned synthesis modeled a circular string from which masses were hung with springs and dampers. Scanned Synth VST follows that model, with controls for the model's physical parameters (see Fig. 3). You can modulate each of those physical parameters with LFOs or ADSR envelope generators, move the onscreen controls with the mouse, and assign each of them to a MIDI controller. Manipulating the physical parameters corresponds to the actions of the performer in the scanned synthesis model. The output of the model is fed to four familiar synth effects: flange, chorus, filter, and reverb. A Master page has controls for the amplitude envelope, portamento, and pitch modulation.

Because Scanned Synth VST's controls affect a mathematical model of a physical process, their aural effect is not easy to grasp. Tweaking a slider or knob may have no effect or may produce a surprise akin to stepping on a cat's tail (see Web Clip 3). Most of the 70 or so factory presets are the edgy, evolving ambiences that you would expect from a physical model run amok, but some (Harpsidron, Fretless, and Slow String 2, for example) show that you can also get delicate, playable sounds. Electronic ambience is clearly the name of the game here.

Scanned Synth VST has a clever and useful randomize feature for which you can specify the degree of randomization for different sections of the model. For instance, you can turn randomization off for the effects, modulator, and output sections and randomize only the scanning parameters. If you don't have a firm grasp of each control's function, that's probably as good a way as any to create new sounds. Scanned Synth VST is definitely worth a listen — it's different.

KV331 Audio

SynthMaster ($99, Win, standalone/VSTi/RTAS)
SynthMaster is the most modular of these synths. It has three oscillators and an audio input. They can be combined or split in various ways before being processed by three multimode filters, which can operate in series or parallel (see Fig. 4). Because of the audio input, you can use SynthMaster as an effects processor. The effects bus is unusually robust and includes a vocoder, 8-band parametric EQ, echo, tremolo, chorus, and reverb.

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FIG. 4: You can configure which eight parameters are accessed on SynthMaster''s Easy page.

Each oscillator's output is the sum of eight user-configurable waves. For each wave, you select a waveform — sine, triangle, square, sawtooth, or white noise (first operator only) — a harmonic number, a frequency offset, and a mode — add, subtract, or multiply. For example, subtracting sawtooth waves with different phases produces variable-width pulse waves, and multiplying waves results in ring modulation. The combined output feeds a waveshaper and a 20-band EQ. Finally, each oscillator has its own amplitude and frequency envelope.

The filters' 23 modes include lowpass, highpass, bandpass, and band reject with various slopes and characteristics, including a fat-sounding analog-saturation emulation. The filters feed distortion units, which you can bypass. Each oscillator can feed its own filter, or a mix of the oscillators can feed all filters arranged in series or parallel.

You can apply four general-purpose modulators either singly or in combination to most oscillator, filter, and effects parameters. Each modulator is an enveloped oscillator with DC offset. The oscillators can run at low-frequency or audio rates and offer a variety of waveforms including random and user-defined step sequences. Two additional tempo-synced MIDI LFOs generate MIDI controller data that you can route simultaneously to 16 different destinations. A highly programmable arpeggiator rounds out the complement of modulators.

SynthMaster presents a programming challenge; its eight tabbed views reveal dozens of sliders, knobs, and buttons. But the detailed manual and 148 tutorial presets will get you as deeply into this synth as you want to go. You can also mix and match settings from the hundreds of factory presets by copying and pasting complete tabs or subsections of a tab (see Web Clip 4).


Alpha 3 ($79, Mac/Win, VSTi/AU)
Alpha 3 is about as classic as it gets. Two oscillators and a noise generator feed a multimode filter followed by an amp. The filter and amp have dedicated ADSR envelope generators. For effects you get chorus. A little ring modulation, three LFOs, and a 7-row modulation matrix are thrown in for good measure (see Fig. 5). But if you're thinking ho-hum, think again. Alpha 3 is one of the best-sounding and easiest-to-program synths covered here, and it comes with a huge collection of presets to prove the point (see Web Clip 5).

Each of Alpha's two oscillators is actually a dual-waveform generator with a control for interpolating between the waveforms, and each waveform has its own octave-range setting. Thirty single-cycle waveforms provide a rich variety of starting timbres, and morphing expands on those enormously. Beyond that, you can modulate waveform symmetry and amplitude. You can use the ring modulator to ring- or amplitude-modulate the second oscillator with the first.

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FIG. 5: Alpha 3 is a classic analog-modeled subtractive synth with a huge preset library.

Alpha's resonant filter has four modes: 12 and 24 dB lowpass, 12 dB bandpass, and 12 dB highpass. You can overdrive the filter as well as modulate its cutoff at audio rates from either oscillator or the noise source. The effect is similar to FM, and when combined with Alpha's ring modulation, it produces many of the rich, evolving timbres found in Alpha's ambient and pad presets. You can apply the filter envelope positively or negatively with an optional timed fade-out during the sustain period.

Much of Alpha's charm comes from its simplicity. Everything is well organized on a single panel, and except for a few of the finer points, you can almost dispense with the manual. If you have any experience with classic analog-synth programming, you'll have Alpha 3 speaking your language in no time.


Pocas (free, Win, VSTi)
Pocas ranks with Scanned Synth VST as one of the most unusual synths here. It is based on additive synthesis, but its implementation differs from that of any additive synth you may have encountered. Once you've chosen the number and spacing of the harmonics, the fun begins.

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FIG. 6: In Pocas, each additive harmonic is represented by a moving dot in the two-dimensional Global display.

Each harmonic is represented by a particle floating in a two-dimensional window (see Fig. 6). You set each particle's mass, charge, and speed, and a variety of enigmatically named variables that determine how the particle's motion affects the sound. For example, a particle's position might modulate its pitch, its volume, or the cutoff frequency of a global lowpass filter, among other things (see Web Clip 6).

Global controls affect the pattern, speed, and overall pitch variation as well as ADSR envelope parameters for the resonant lowpass filter and output amplifier. Context menus offer preset harmonic patterns (sawtooth, square wave, and so on); 5, 20, and 100 percent randomization; and the mode of motion — particles orbiting or chasing each other.

This synth has no documentation and few presets. It's definitely for the experimentalist, but a little perseverance will produce lush, evolving, additive ambiences.


Modelonia ($79, Win, VSTi)
Modelonia starts with mathematical models of sound generation in acoustic instruments. The models involve a vibrating resonator to produce the sound and some form of stimulus to start the resonator vibrating. For resonators, Modelonia gives you string and horn models. For stimulators, you get a pick (applied to the string), vibrating lips (applied to the horn's mouthpiece), and noise, which you can apply to either resonator. The string and horn models differ in that the horn resonator is fed back to its stimulator to produce sustained sounds, whereas once plucked, the string resonator dies out over time.

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FIG. 7: Modelonia combines plucked-string and blown-horn physical models to create intriguing hybrid instruments.

The essential part of programming Modelonia is setting the characteristics of the stimulators and resonators (see Fig. 7). For example, you can control the shape and amount of the pick's effect on the string; the rate and amplitude of the lip vibration; the brightness and pitch of the horn resonator; and the stiffness, pitch, and EQ of the string resonator. In an unnatural touch, you can also feed the output of either resonator as a stimulus to the other, and simultaneously doing both produces many interesting cross-feedback effects. You can also adjust the mix of the string and horn resonators to model hybrid instruments not found in nature.

Although effects and modulation are not the name of the game, Modelonia does have two LFOs and an ADSR envelope generator, each of which can be routed to various sound-generating parameters. The output stage contains an EQ designed to simulate resonating bodies and a basic reverb geared toward emulating small rooms. Finally, there are individual tuning adjustments for each note between A3 and G#6 for each resonator. Those are sometimes needed to compensate when the resonator's characteristics force it slightly out of tune for specific notes.

Modelonia ships with a bank of 128 factory presets along with 10 Sound wizards, which serve as good starting points for creating your own sounds. But tweaking the factory presets is probably the best way to get up and running on this synth. The best thing about physical modeling is that the sound is almost always organic, even if not precisely like an acoustic instrument (see Web Clip 7).

Progress Audio

Soup ($85, Win, VSTi)
Soup is an additive synth with an unusual approach that takes much of the tedium out of creating additive waveforms. It also implements robust, vectored sound morphing. You amass presets around the perimeter of Soup's Morph Bowl, then use the mouse, built-in automation, or MIDI to morph among the sounds (see Fig. 8 and Web Clip 8).

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FIG. 8: Soup morphs among any number of presets placed around the Morph Bowl in the center.

Soup gives you three ways to create additive waveforms. With the standard method, common to most additive synths, you use a bar graph to set the level, tuning, and pan position of each of the up to 64 partials. You then use breakpoint envelopes to change those parameters over time. The second option is to resynthesize an additive waveform, including its evolution over time, from any WAV file at your disposal. The third option, unique to Soup, is called the Elements Editor. It incorporates five Bowls to shape characteristics of the sound: Tone, Tone Shift, Pan, Tuning, and Volume Envelope. As with the Morph Bowl, you add preset waveforms around the perimeter of each bowl, then position a central cursor to define the mix of those waveforms. This provides a very fast way to get complex, evolving waveforms.

Soup has six basic effects: reverb, feedback delay, distortion, chorus, multimode filter, and formant filter. Modulators include two LFOs and a breakpoint envelope generator. Those, along with various MIDI controllers, are routed to parameters using an 8-row modulation matrix. Soup is a very capable additive synth, but it's the patch morphing that makes it stand out from the crowd.


Vanguard ($89.99, Mac/Win, VSTi/AU)
With Vanguard, it's back to familiar territory — a 3-oscillator subtractive synth with two ADSR envelope generators, three LFOs, arpeggiation, gating, delay, and reverb (see Fig. 9). What distinguishes Vanguard is excellent sound quality, ease of use, and what it does with its basic assets. Three banks of 128 presets show that Vanguard covers the bases for classic analog sounds.

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FIG. 9: Combining Vanguard''s Trancegate, arpeggiator, and delay line produces lots of rhythmic variety.

The oscillators have 31 waveforms, including 6 random forms ranging from the sample-and-hold-like R2D2 to white noise. Two of the waveforms, Sine AM and Sine FM, provide basic modulation timbres. Each oscillator has a dedicated triangle-wave LFO that you can route to tuning, pulse-width, and filter cutoff. Using more than one of the LFOs to modulate filter cutoff produces complex filter patterns.

Vanguard's multimode filter has resonant lowpass, highpass, and bandpass modes with 6, 12, and 24 dB per octave slopes along with several multiband configurations. The filter is followed by delay and reverb effects and an output section with overdrive distortion. You can route each of the two ADSR envelope generators to volume, filter cutoff, pulse width, and oscillator tuning.

The Trancegate and arpeggiator provide flexible, tempo-based modulation. The gate has 16 steps, variable attack and decay, separate stereo channels, and an amount control that balances between the gated and ungated signal. The arpeggiator has five modes — up, down, alternating, random, and play-order — and the rate and duration are set separately. You can generate a lot of action using the Trancegate, arpeggiator, and delay together (see Web Clip 9).

Rick Jelliffe

Neumixturtrautonium ($29.95, Win, VSTi)
Neumixturtrautonium is a variation of a variation of an early (possibly the first) electronic musical instrument, the Trautonium, invented by Freidrich Trautwein in the 1930s. German physicist and Trautonium virtuoso Oskar Sala made significant modifications, most notably the introduction of subharmonic synthesis, in the Mixtur-Trautonium. Neumixturtrautonium is a noble attempt to realize the Mixtur-Trautonium as a VSTi plug-in.

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FIG. 10: Neumixturtrautonium has four subharmonic oscillators and uses the MIDI Mod Wheel to select one of three subharmonic configurations.

Subharmonic synthesis uses frequency dividers to create new waves whose frequencies are whole-number divisors of the source wave. The subharmonics have the same waveform as the original, typically a sawtooth. A combination of four subharmonics is called a mixture or bank, and in Neumixturtrautonium you select between three banks with the Mod Wheel. In each mixture, each subharmonic has its own filter, and you can switch the filters between formant and resonant lowpass modes (see Fig. 10).

Depending on the subharmonic levels and frequencies, a note played on Neumixturtrautonium might sound like a single note or a chord. Furthermore, just as with higher harmonics, some of the subharmonics may not be in the equal-tempered scale. Because subharmonics are harmonically complex (not sine waves) and lower in pitch, they dominate. In short, Neumixturtrautonium does not always play nicely with others, but you can, with some effort, retune the subharmonics. A basic reverb and pitch-shifter round out the signal path.

Neumixturtrautonium comes with no manual and only 16 presets, but the presets show that this instrument has an unusual sound palette. Variations range from ethereal string and choral sounds to mechanical-industrial effects (see Web Clip 10). It's worth your time to try it out, and the shareware fee is quite reasonable. You'd be hard-pressed to re-create its sound on another synth.

Sonic Charge

MicroTonic ($89, Mac/Win, VSTi/AU)
No plug-in library is complete without a drum machine. With the availability of excellent sampled drum libraries of every stripe, a high percentage of drum machine plug-ins are specialized sample players with built-in step sequencers. Synthesized drum machines are harder to find, and despite its modest price, MicroTonic is one of the most versatile. It also comes with a huge collection of drum patches and programs (patches for each pad with accompanying sequences).

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FIG. 11: MicroTonic is a classic synthesized drum machine featuring a 12-pattern 16-step pattern sequencer to play its oscillator and noise sound generators.

MicroTonic is an 8-pad drum synthesizer with a built-in pattern sequencer capable of holding 12 patterns (see Fig. 11). Patterns have from 1 to 16 steps, and you can chain adjacent patterns together to create longer patterns (see Web Clip 11). Step size ranges from eighth to 32nd notes, triples are included, and you can use the Swing slider to shift even-numbered steps. Each step has accent and fill buttons; the fill button creates a flam at from one-half to one-eighth the step size. A context menu allows patterns to be copied, pasted, and automatically altered in various ways. You can export pattern chains as either MIDI or audio files. Exporting MIDI is especially handy for dequantizing your drum patterns.

MicroTonic's drum synth has eight pads, which can be triggered by MIDI with or without the pattern sequencer. You can, for example, create basic drum parts in the pattern sequencer, then spice them up with long, nonlooping MIDI parts. With the multioutput version of the plug-in, you can route each pad to its own output for individual processing.

Each of MicroTonic's drum pads has an identical synthesis engine consisting of an oscillator section, a noise section, and a mixer for balance, EQ, and distortion. The oscillator section has a 3-mode oscillator (sine, triangle, or sawtooth), a bipolar pitch modulator with random, sine-wave LFO, or decay envelope as sources, and an AD volume envelope. The modulator is the key here, providing everything from naturally falling drum pitch to rattle- and shaker-style percussion. The noise section feeds white noise through a multimode resonant filter. The level is controlled by an AD envelope with exponential, linear, and retriggering decay modes. Retriggering is useful for stuttering sounds like handclaps.


Zoyd (free, Mac, AU)
Zoyd is a prototype for the commercial (not free) plug-in synths subsequently released by U-he. Consequently, it suffers a few limitations such as no further development, monophonic operation, minimal documentation and preset library, limited optimization, and occasional unexpected clicks and pops. So why include it? Because it sounds different, is different, and offers a lot to play with.

Zoyd's sound generators are two oscillators and a noise generator. The oscillators have three waveforms and unique Morphology and Variance controls whose effect depends on the selected waveform. Waveform Saw o/e is the most interesting; Variance detunes the odd versus the even harmonics, and Morphology adjusts their volume (amplitude) ratio.

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FIG. 12: Zoyd''s two oscillators are followed by filters, waveshapers, and a mixer whose signal routing can be reconfigured.

Zoyd's signal path splits after the sound generators and thereafter is somewhat configurable — you can choose from nine configurations. These arrange a pair of filters, a pair of waveshapers, and a mixer in various ways. For example, each oscillator can feed its own filter, after which the signal is mixed and sent through the waveshapers in series, or oscillator 1 can feed a waveshaper and filter in series, then be mixed with oscillator 2 to feed the second waveshaper and filter in series. The signals appearing at the mixer can be added, subtracted, or ring-modulated. Along the way, you can modulate most parameters with any of three ADSR envelope generators and two LFOs (see Fig. 12).

Being monophonic and aggressive-sounding, Zoyd is best for leads and basses. It can also have a decidedly vocal quality, which is evident in many of the factory presets (see Web Clip 12). You may not use this synth in every piece, but when you do you'll get the listener's attention.

More Is More

It's tempting to say that this roundup covers the Alpha to Zoyd of budget virtual synths, but in truth it barely scratches the surface. A little exploration will turn up dozens of picks in every category, and most of them have something unique to offer. Beyond that, they're usually underexposed and therefore not overused. A little time on the Web instead of leafing through your existing preset library might just turn up that perfect sound.

Len Sasso is an associate editor of EM. For an earful, visit his Web site



Humanoid Sound





Rick Jelliffe