Twelve Under a Hundred

Mar 1, 2007 12:00 PM, By Len Sasso

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.

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.

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).

LinPlug

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.

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.

Mutagene

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.

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.