JUCE is an open-source cross-platform C++ application framework for desktop and mobile applications, including VST, VST3, AU, AUv3, LV2 and AAX audio plug-ins.

C++ Audio Plug-in Framework for desktop, mobile and web

AudioKit Synth One: Open-Source iOS Synthesizer App

Physical modelling signal processing for analog tape recording

Full App: iOS Standalone and AUv3 Plugin Example. Work in Progress.

AUv3 MIDI Tape Recorder

A collection of templates for creating Audio Unit V3 in Xcode

Powerful polyphonic synthesizer for iOS that relies on sound fonts for generating audio - https://bradhowes.github.io/SoundFonts/

(WIP) MIDI Sequencer Audio Unit

ML Audio plug-in example using iPlug2 & ONNX Runtime

A great start point for making AUv3 MIDI sequencer apps.

Utilities related to the new version 3 Audio Units

An AUv3 MIDI plugin. See the blog post

Decent Sampler Sounds

Creating Custom Audio Effects - Simple Universal Version (Mac Catalyst)

Routes white keys from midi-input to chosen scale to midi output

Simple example of an AUv3 MIDI app

AUv3 AudioUnit low-pass filter for iOS and macOS

Simple host for a collection of the same AUv3 component

RhythmBud's Editor Code