Welcome to issue 24 of objc.io. This month is all about audio.

We already featured two issues about photos and video this year, so it follows that this month's issue completes our media series with the missing piece: audio.

Jack Schaedler recently wrote a fantastic introduction to signal processing, and he opens this issue with an article explaining the concepts behind the "Hello World!" of audio processing apps: tracking the pitch of a monophonic musical performance. (The beautiful illustrations are his work too!)

Next up, Chris writes about functional signal processing with Swift, and Aaron looks at the topic of audio from a different perspective: sound design for products. Finally, if you're new to the sometimes confusing multitude of audio frameworks on Apple's platforms, Daniel and Florian provide a high-level API overview.

Best from Berlin,

Chris, Daniel, and Florian.