audioGraph universal arrives

Another slightly more experimental looking synth arrives for the iOS.

iOS Audio Processing Graph Demonstration

“An audio processing graph is a Core Foundation opaque type, AUGraph, that you use to construct and manage an audio unit processing chain. A graph can leverage the capabilities of multiple audio units and multiple render callback functions, allowing you to create nearly any audio processing solution you can imagine.” – From Apple’s “Audio Unit Hosting Guide For iOS”

AudioGraph is a superset of Apple’s MixerHost application.

Features include:

  • Mono and stereo mic/line input
  • Audio effects including:
  • Ring modulator
  • FFT passthrough using Accelerate vDSP framework
  • Real-time pitch shifting and detection using STFT
  • Simple variable speed delay with using a ring buffer
  • Recursive moving average filter with variable number of points
  • Convolution example with variable filter cutoff frequency
  • Stereo level meter
  • Synthesizer example – sine wave with an envelope generator
  • iOS 5 features (from Chris Adamson) including:
  • MIDI sampler audio unit
  • file player audio unit
  • audio unit effects
  • Runs on iPad, iPhone, and iPod-Touch
  • Open source
  • Music by Van Lawton
  • Everything from MixerHost


  • A device that runs iOS 5.x
  • Headphones.

Launch the app and press Play.

Source code, documentation, support:

This project is derived from work by:

  • Chris Adamson
  • Stefan Bernsee
  • Michael Tyson
  • Stephen Smith
  • Contributors to the Core-Audio mailing list
  • Contributors to stack
  • Apple’s iOS developer program,

The app is free.
audioGraph - Tom Zicarelli Clip to Evernote

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