Virtual Acoustic Feedback
Virtual Acoustic, aims, among its objectives, at the reproduction of acoustic spaces and sources. Virtual Acoustic Feedback (VAF) research targets the interaction of instruments and devices in a virtual acoustic space, with specific attention to acoustic phenomena including apparati acting as transducer and actuator, connected in feedback loop and including at least one active device able to sustain the feedback. VAF research targets the emulation of acoustic feedback (e.g. guitar howling) and its extension to new synthesis scenarios.
This page summarizes research conducted on this topic and collects open source tools for VAF.
- L. Gabrielli, M. Giobbi, S. Squartini, V. Valimaki "A Nonlinear Second-Order Digital Oscillator for Virtual Acoustic Feedback", to appear in Proc. ICASSP 2014, Florence, IT
- L. Gabrielli, M. Giobbi, S. Squartini, V. Valimaki "Adaptive Digital Oscillator for Virtual Acoustic Feedback", to appear in Proc. AES 134th Convention, Berlin, DE
- A short video demonstrating guitarist A. Ascolani getting to grips with the Puredata patch
- A screenshot of the latest Puredata patch
Tone recorded in an anechoic chamber, with a Peavey amplifier and Fender guitar. The guitar output was sent to a digital recorder and the amplifier. The amplifier sound was recorded with a microphone and sent to the digital recorder.
- A2 - recorded at the amplifier - howling appearing at 5th partial
- A2 - recorded at the guitar output
Matlab simulation with Sullivan's method 
Matlab simulation with the proposed oscillator
PureData real-time synthesis with the proposed oscillator
- The dry + wet signals appearing in the AES paper (Fig.3), howling pitch = 1.5*F0
- Puredata externals and patch for guitar howling emulation (including Triode vacuum tube model). Compiled for Linux and Mac Os X only.
 Charles R Sullivan, “Extending the Karplus-Strong algorithm to synthesize electric guitar timbres with distortion and feedback,” Computer Music Journal, vol. 14, no. 3, pp. 26–37, 1990.