A Brief Exploration of Electronic Music and its Theory

By: Zac Changnon

Sound Generation There are two very general techniques for

creating sound electronically: Synthesis Sampling

• Both are widely used today and have undergone many evolutions from their early days.

Synthesis

Electronic synthesis is the fabrication of sound from varying (oscillating) electronic signals, or a simulation of such signals.

Many different kinds of synthesis/synthesizers: Analog

Additive Subtractive FM (frequency modulation)

Digital Granular Wavetable Software Modeling/SoftSynth

…and more

More Classifications

Polyphonic/Monophonic Indicates whether a synthesizer can play multiple

notes at once, or just one.

Modular/Non-modular In modular synths, each piece of the equipment (the

sound generators, filters, amplifiers, and so on) are literally separate blocks that can be wired together in different ways.

How it Works

Basic analog synthesis is based on the manipulation of basic waveforms, like a sine wave:

The horizontal axis is time, while the vertical axis is voltage. This oscillating voltage is applied to a speaker, which turns it into sound. It is probably amplified first.

How it works, cont’d

Higher notes correspond to a higher frequency wave:

•Lower notes correspond to lower frequency waves:

How it works, the end

Most analog synthesizers operate on at least two wave forms simultaneously. These waves are combined in various waves to produce the wave which makes the final sound. In subtractive synthesis, two waves are subtracted to give a final sound wave, like so:

After the generation of the wave, many effects are often applied between the oscillators and the speakers. Frequency filters can dampen or add warmth to sound, amp envelopes can alter the attack and decay rates, and low frequency oscillators and other effects can be applied to add color to the overall sound.

A brief history of synthesizers

The earliest synthesizers used simple oscillating circuits and date as far back as 1876.

Synthesizers in recorded and popular music, however, did not come into play until much later.

One of the most famous early synthesizers to gain some notoriety was Robert Moog’s “Moog” modular synthesizers, which he first built in 1963.

A Moog

History, the end

Synthesizers have changed a great deal in both sound and appearance since the Moog.

Today, analog synthesis is often modeled on a computer by a software synthesizer, or “SoftSynth,” like Propellerheads’ “Rebirth”, shown below:

Sampling

Sampling can refer to many things, but in this case it refers to the use of sampler, a digital device which can play back (usually short) samples of just about anything, at various pitches by speeding up for slowing down the sound (adjusting its frequency).

When connected to a keyboard, a musician can play whatever sounds are loaded into the sampler.

Sampling

Sampling has a variety of applications. Some sophisticated sample libraries exist which allow a musician to obtain, for example, a very realistic orchestral sound with only a keyboard and a sampler.

This is one of the reasons sampling is so widespread today; it allows one musician to accurately simulate a wide variety of non-electronic instruments.

Sampler Example

One of the biggest players in the sampler market for years has been Akai. This is what their S3200 rack sampler looks like:

Modern Samplers Like synthesis, sampling is a practice that has lately been moving more and more

onto computers, away from dedicated hardware like the Akai. An extremely powerful (and expensive!) example is Nemesys’ GigaStudio software sampler:

Sound Samples

Simple Sine Wave Tone:

•Simple sine wave musical phrase:

•The same phrase, with a subtractive sawtooth and some filtering:

•And some simple background instruments and harmony, and we get:

References

http://www.propellerheads.se http://www.udel.edu/idsardi/sinewave/sinewave.html http://www.obsolete.com/120_years/ Propellerheads’ Reason documentation http://www.code404.com/synths/akai.html http://www.soundforge.com/download/freewallpaper.asp http://www.sospubs.co.uk/sos/nov00/images/

gigastudio1.l.gif http://profs.sci.univr.it/~dafx/Final-Papers/pdf/

Chowning.pdf