Feedback control of acoustic musical instruments: collocated control using physical analogs

Area of Science:

• Musical Acoustics
• Control Theory
• Signal Processing

Background:

• Traditional musicians rely on numerous instruments with fixed acoustic properties.
• Modern musicians seek versatile instruments with programmable acoustics.
• Feedback control offers a pathway to dynamic acoustic manipulation.

Purpose of the Study:

• To present a theory for stable feedback control of acoustic musical instruments.
• To make feedback control concepts accessible to the musical acoustics community.
• To explore practical design considerations for programmable musical instruments.

Main Methods:

• Describing a stability-guaranteed control strategy: collocated sensors/actuators and emulation of physical analog systems.
• Presenting fundamental feedback controllers and their corresponding physical analog systems.
• Discussing the effects of these controllers on instrument acoustics.

Main Results:

• Identified collocated sensors and actuators with analog emulation as the only universally stable control strategy.
• Demonstrated how fundamental controllers alter instrument acoustics.
• Provided a theoretical explanation for why manipulating resonance frequency demands more power than decay time.

Conclusions:

• Stable feedback control of acoustic musical instruments is achievable through specific strategies.
• Understanding controller effects and design challenges is crucial for developing programmable instruments.
• The presented theory provides a foundation for future research in electroacoustic music and instrument design.