Synth Secrets

This time, Gordon Reid explains how various analogue synth manufacturers attempted to create workable polyphonic synths by employing digital technology.

Having explored the way monophonic and duophonic analogue keyboards work, Gordon Reid puts away his Minimoog and Odyssey and descends into the complex world of polyphonic synths to a flourish of complex jazz chords.

Gordon Reid discovers that two's company, as he investigates how manufacturers stretched the capabilities of analogue monosynths to offer the magnificent total of two notes at a time...

In these days of 64-note polyphony and 32-part multitimbrality, it's easy to forget the importance of note-priority systems in analogue monosynths — yet they can have a drastic effect on what you hear when you play or trigger an old synth. Gordon Reid provides a refresher course.

Sample & Hold modules, as explained last month, convert a continuously varying signal into a stepped series of fixed pitches. And this, as we shall see, is the basis of what we know as 'digital audio'...

Gordon Reid introduces the synthesis modules that allow you to create a number of commonly used 'random' effects, and their close relatives — analogue sequencers.

We turn our attention to the effects that can be achieved when subtractive synthesis components are applied not to the output from oscillators, but to real-world sounds — such as human speech.

Every pitched sound can be thought of as a collection of individual sine waves at frequencies related to the fundamental. Gordon Reid introduces a powerful method of synthesis that works by manipulating these individual harmonics.

Last month, we examined the frankly scary maths allowing you to predict the audible effects of Frequency Modulation. This time, although the maths gets even tougher, Gordon Reid relates the theory to the practical implementation of FM synthesis on Yamaha's digital synths, as well as modular and non-modular analogues.

As explained last month, audio-frequency modulation of the amplitude of a signal can be a powerful synthesis tool. The possibilities expand still further when we consider what happens when you use one audio-frequency signal to modulate the frequency of another...

Last time, we examined the concept of modulation at low frequencies. This month, we speed things up a bit. The result is not just faster versions of the same modulation effects, but a new type of synthesis...

In this month's instalment of his series on the basics of subtractive synthesis, Gordon Reid considers the magic ingredient that makes all the other elements sound interesting...

Having laid bare the inner workings of oscillators, contour generators and filters, Gordon Reid turns his attention to something which at first sight seems entirely self-evident. Can the humble voltage-controlled amplifier really hold any Synth Secrets?

Gordon Reid reveals some of the limitations of the 'classic' ADSR envelope with reference to a practical synthesis example, and explains some of the different types of envelopes found on 'classic' analogue synths, from AR envelopes right up to highly flexible digitally controlled EGs.

You press a key on your synth. It plays a note. That's it, right? Wrong. We explain the role of envelopes, gates, and triggers in this deceptively simple process.

As Parts 4 & 5 of Gordon Reid's series showed, even the simplest analogue filters mess with your sound in complicated ways. In this Part, he considers what happens when you make the design more sophisticated...

Gordon Reid continues his series on the theory of subtractive synthesis by delving deeper into the amazingly complex world of the analogue audio filter.

Having dealt last month with the concepts of envelopes, oscillators and LFOs, Gordon Reid moves on to the subject of filters, and the havoc they wreak on the signals that pass through them.

We move on from discussing the harmonic components of sound to explaining how they change over time, and some of the tools subtractive synths give you to emulate this process.

In Part 1 we explained how the tones of most real instruments can be reduced to patterns of harmonics, which can be generated using sine, saw, square or pulse waveforms. This month, we consider the sonic raw materials needed to imitate unpitched percussion.

How to find this classic multi-part 'synthesis explained' tutorial series on the current Sound On Sound site.