Nuts & Volts - March 2006

Analog music synthesizers — the kind with all the knobs and patch cords — were extremely popular 10 to 15 years ago. In those days, the name Moog (pronounced like vogue) was a household name.

Digital music synthesizers eventually overshadowed the popularity of the analog ones and a steady stream of ever-improving computer-driven instruments continues to line the shelves of music stores.

Today, however, whether due to nostalgia or the same thing that drives old clothes back into style, analog synthesizers are seeing a resurgence of popularity.

■ FIGURE 1. Sound Lab Mini-Synth Block Diagram.

BUILD THE SOUND LAB MINI-SYNTH SOUND SYNTHESIZER

This article will show you how to build a very cool analog sound synthesizer. You will learn about analog sound generation, have a great project building experience, and have hours of sound synthesizing fun. I would say that the difficulty of this project is somewhere between an intermediate and advanced level. It involves making a printed circuit board, fabricating a front panel and case, and a good bit of wiring and soldering. I think you will find it well worth the effort. I am making PC boards available for sale from my website, if you would rather not etch one yourself. I invite you to visit my website at www.musicfromouterspace.com and hear the Sound Lab Mini-Synth for yourself.

Introduction

Refer to Figure 1. The Sound Lab Mini-Synth is a battery-powered analog sound synthesizer complete with two voltage controlled oscillators (VCOs), a white noise source (Noise), a mixer (MIX), one voltage controlled state variable filter (VCF), one voltage controlled amplifier (VCA), an attack release envelope generator (AR), and one low frequency oscillator (LFO). Together, these modules provide sound sources, sound modifiers, and modulators — the tools to create a wide range of electronic sounds. Let’s take a look at each module in detail.

Attack Release Envelope Generator

The Attack Release Envelope Generator (AR) is one of the Sound Lab’s modulators (see Figure 2). It produces a voltage which rises and falls at a rate set by the attack and decay pot settings, respectively. The higher the knob setting, the longer the rise (attack) or fall (decay) time of the voltage produced by this module.