JG Electronics

Audio Graphic Tool

Chen Kok has written a Cocoa interface a free and open source Audio Library for Core Audio.

With this library it should be rather easy to write audio apps that uses sound input and / or output.

A Programming Guide comes with the Audio Library as well so it is excellent documented.

Both the library and programming guide you can download from Chen’s website http://www.w7ay.net/chen/

On Chen’s website you also find 3 example XCode projects: Generator, Oscilloscope and Play Through.

I extended Audio Tool with Chen’s graphic display from his Oscilloscope project.

If you like to write an audio wave for Audio Tool you write it first in the Audio_ToolController class and send 512 samples to the Display class to see the wave form in the graphic view. If the wave form is correct and stays correct during frequency and amplitude variations then you write the same code for the audio wave in the Audio_ToolModel class.

I developed the triangle wave form this way and developed an unusual formula for the triangle wave form.

Audio Tool with Graphic Display is full Cocoa and that means all classes end on .m.

The MVC design pattern is followed in Audio Tool with Graphic Display, there is a Controller, Model and Display class.

The build requirements for this project are Mac OSX10.7 and XCode4.1

The runtime requirements are Mac OSX10.6 or later.

The display class is from Chen Kok W7AY. See HAM Radio Projects for other projects from Chen.


The application icon is from Vincent Garnier.


If you have questions about programming topics please ask these questions on a developer mailing list from Apple. There you find people with far more knowledge then I.

For questions concerning Core Audio goto: coreaudio-api@lists.apple.com

For books about the foundation of Cocoa Programming visit: www.bignerdranch.com

Other useful books:

C++ From the Beginning, author Jan Skansholm.

Cocoa Programming Developer’s Handbook, author David Chisnall.

Core Audio, authors Kevin Avila and Chris Adamson.

If you have remarks or if you find bugs please send me an email: jgelectronics@icloud.com

Click on the picture to download the application and the source code.

Happy Coding!


© JG Electronics