For the past four years I’ve been an author on Ray Wenderlich’s website which provides tutorials for iOS developers. I don’t do much native iOS development these days, However, I do like to keep my skills up to date. As part of this team I sometimes find myself being assigned topics that I wouldn’t otherwise look into. And so it was, a couple of months ago, that I received an assignment to write a tutorial on the open source AudioKit project.

AudioKit is a fascinating library for audio synthesis, processing and analysis, that has its roots in Csound, an MIT project from 1985. The library contains a mixture of C, C++, Objective-C and Swift. However, it is with Swift that this project really ‘comes to life’. You can create audio processing pipelines, in near-realtime, directly within Xcode playgrounds. This makes the topics of synthesis and processing very accessible.

Furthermore, some of the concept within AudioKit, oscillators, modulation and ADSR envelopes took me right back to some of my earliest experiences of audio, with the 8-bit BBC Microcomputer. With this in mind I decided to write an article about the history and science of sound synthesis using AudioKit to demonstrate the principles within Xcode playgrounds.

The tutorial takes the reader on a journey from the basic oscillators and the physics of sound, instruments such as the Theremin, through ADSR envelopes and filters, the Novachord and Hammond organs, additive synthesis, polyphony and the Yamaha DX7. It finally finishes up at sound sampling, bit-crushing and mixing.

Unfortunately the 4,000 word limit meant I had to leave out a lot of history, and a lot of AudioKit functionality. However, it was a lot of fun writing it. If you’re interested, why not pop over to Ray Wenderlich’s site and take a look?

Regards, Colin E.