Real-Time Analysis of Sensory Dissonance

We describe a tool for real-time musical analysis based on a measure of roughness, the principal element of sensory dissonance. While most historical musical analysis is based on the notated score, our tool permits analysis of a recorded or live audio signal in its full complexity. We proceed from the work of Richard Parncutt and Ernst Terhardt, extending their algorithms for the psychoacoustic analysis of harmony to be used for the live analysis of spectral data. This allows for the study of a wider variety of timbrally-rich acoustic or electronic sounds which was not possible with previous algorithms. Further, the direct treatment of audio signal facilitates a wide range of analytical applications, from the comparison of multiple recordings of the same musical work to the real-time analysis of a live performance. Our algorithm is programmed in C as an external object for the program Max/MSP. Taking musical examples by Arnold Schoenberg, Gérard Grisey and Iannis Xenakis, our algorithm yields varying roughness estimates depending on instrumental orchestration or electronic texture, confirming our intuitive understanding that timbre affects sensory dissonance. This is one of the many possibilities this tool presents for analysis and composition of music that is timbrally-dynamic and microtonally-complex.