Look at the architecture of the Core Audio API and compare it to the parent article: https://developer.apple.com/library/mac/documentation/MusicAudio/Conceptua

Look at the architecture of the Core Audio API and compare it to the parent article: https://developer.apple.com/library/mac/documentation/MusicAudio/Conceptual/CoreAudioOverview/CoreAudioEssentials/CoreAudioEssentials.html https://developer.apple.com/library/mac/documentation/MusicA... Besides the fact that you are writing in C/Objective C, most heavy lifting is being provided by Audio Units which are specifically designed with common datatypes to be chained, composed and executed in low-latency situations. Furthermore, most common things you would need in your app like mixing, conversion, timing, etc are provided as highly optimized services by the system.