How To Perform Modular Synthesis

Soundtrack: "East River Dawn" - Laurie Spiegel - The Expanding Universe (Philo - 1980)

Are you tired of the sort of synthesis essays which dominate the classroom as of late? Well, I am offering some respite from this form so that you might learn about "modular synthesis." Modular synthesis involves the creation of a unique sound or "patch" by using hardware called modules which can be connected and then played according to some input. These modules offer different ways to transform the sound being created, and the parameters can be altered to alter the results. This is no method of essay writing; it is the classic creation of electronic music in its most pure form.

You must first acquire the means to synthesize. Actual modular synthesizers are hard to find and often expensive, but there do exist digital versions and even software emulators.

The sound of a synthesizer does not simply materialize from nothing; it must be produced. An "oscillator" must be triggered. This oscillator is the basis of all that is to follow. It simply produces a "waveform." A waveform is a sound wave of a particular shape, there being four basic waveforms: the sine-wave, the square-wave, the triangle-wave, and the sawtooth-wave. Each synthesizer has at least one oscillator and hopefully as many as two or three. Simply turn one on and choose a waveform. The sine-wave looks like a sine graph and is the smoothest sounding of all. The square-wave is like a rigid sine-wave, and consequently, it sounds more distorted and rougher. Many classic video-games use square-waves liberally. The triangle wave is a sine-wave that comes to points instead of curves and is somewhere in between the sine and square. Finally, the sawtooth-wave looks exactly like a sawblade and has a grainy quality to it. It is a very common waveform in music, especially since it can be used to reproduce physical instruments.

After choosing a waveform, you can detune the oscillator if you wish for it to sound more natural and dissonant. You can set the octave of the wave, and even change the wave's particular stereo position. Many modular synths include noise generators, and you can use these to add more grain and, well, noise to the sound.

At this point, it is most common to run the waves through a filter. Filters do just as advertised; they filter particular frequencies and output the remaining. The most common type is a LPF or low-pass filter meaning the low frequencies are allowed through. Others include high-pass filters (opposite of low-pass) and band-pass filters which allow a defined range to pass through. The low-pass filter is often used to soften the sound by removing the harsher, higher frequencies. Once a filter is chose, you can set the amount to be filtered.

The sound then passes through the amplifier which boosts the signal allowing for an appropriate volume. This amplifier has an adjustable gain giving the user the opportunity to make the sound even louder.

There are other modules which can be utilized to further alter a sound which is still simple. First is the LFO or low-frequency oscillator. This oscillator does not generate an audible wave; it generates a wave which can alter other parameters. By directing the LFO at a parameter such as the amplifier's pan, one can alter the stereo position of the sound according to the position of the wave. The frequency and shape of the LFO can be set as well as the strength with which it alters the directed parameter.

The other most common modules are "envelopes." These are not paper pockets which can contain letters; the word is meant in the wave science sense of the word where this envelope is used to define the magnitude of the wave at any given time. These envelopes appear in the form of an amplifier envelope and a filter envelope. The envelope has four main parameters: attack, decay, sustain, and release. The attack on an amp envelope sets the amount of time it will take for the sound to reach its maximum volume; the decay sets the amount of time it will take for the sound to reach its final velocity; the sustain decides the volume of the sound once the decay period has finished; the release decides how long it will take for the volume to return to zero after the note has finished triggering. These same functions can be translated to the filter.

After these modules are utilized, you are free to play with any available effects like delay or chorus. Some synths allow for pitch glide or portamento which allows the synth to slide between notes instead of simply triggering the separate notes. Outside of any effects, you are done constructing a simple patch. Go forth and take hold of modular synthesis with your new-found knowledge.