university of southern california viterbi school of engineering

music computation and cognition laboratory


MuSA.RT - music on the spiral array . real-time

project co-leaders: profs. elaine chew, alex françois


MuSA.RT -- Music on the Spiral Array . Real-Time -- explores the use of Elaine Chew's Spiral Array model in real-time analysis and scientific visualization of tonal structures in music. MuSA.RT allows listeners to see tonal structures as they hear them. MIDI information is mapped to pitch names in real time, and the closest triads and keys are computed and shown as the music unfolds in a performance. Two trackers, each a Centers of Effect (CE), one for longterm and one for shortterm information, show the history of the tonal trajectories. The 3D model dances to the rhythm of the music, spinning smoothly so that the current triad forms the background for the CE trails. Real-time tracking of tonal patterns in music also has widespread applications in music analysis, information retrieval, performance analysis, and expression synthesis.

MuSA.RT was designed using Alexandre François' Software Architecture for Immersipresence, a general formalism for the design, analysis and implementation of complex and interactive software systems.

Photo (left): Composer Lisa Bielawa tries out the MuSA.RT system at the Radcliffe Gymnasium, January 16, 2008.
Photo by E. Chew.



MuSA.RT 2.6 analyzes P.D.Q. Bach




Elaine Chew speaks on the Ties Between Engineering and Music in a Viterbi News video.


Elaine Chew's performance on the piano with MuSA.RT's interactive tonal analysis and visualization is highlighted in Tom Avril's article on Computers have exquisite ears: Analyzing music the digital way in the Philadelphia Enquirer.


Elaine Chew's lecture-concert on The Mathematics in Music at MIT is featured in Larry Hardesty's article in the Technology Review, The Geometry of Sound.


Inaugural presentation of The Mathematics in Music receives coverage in the LA Times by August Brown: Her solution to Sudoku?


An early MuSA.RT system is featured in Rick Keir's IMSC Newsletter article on 'Seeing' the music as you hear it.

peer-reviewed publications

Chew, E. and A. R. J. François (2009). Visible Humour - Seeing P.D.Q. Bach's Musical Humour Devices in The Short-Tempered Clavier on the Spiral Array Space. In T. Noll, T. Klouche (eds.), Mathematics and Computation in Music - First International Conference, MCM 2007, Berlin, Germany, May 18-20, 2007. Springer: Berlin, Heidelberg, Communications in Computer and Information Science (CCIS) Volume 37, 2009. [ PUB | ANN FIGS ]

Chew, Elaine and Alexandre R. J. François (2008). MuSA.RT and the Pedal: the Role of the Sustain Pedal in Clarifying Tonal Structure. In Proceedings of the Tenth International Conference on Music Perception and Cognition, Sapporo, Japan, August 25-29. [ ABS | PDF | REF ]

Chew, E. and A. R. J. François (2007). Visible Humour - Seeing P.D.Q. Bach's Musical Humour Devices in The Short-Tempered Clavier on the Spiral Array Space. In Proceedings of Mathematics and Computation in Music (MCM2007), Berlin, Germany May 18-20, 2007. [ ABS | PUB | PDF | REF ]

François, Alexandre R. J., Elaine Chew (2006). An Architectural Framework for Interactive Music Systems. In Proceedings of the 6th International Conference on New Interfaces for Musical Expression, IRCAM, Paris , June 5-7, 2006. [ ABS | PDF | REF ]

Chew, Elaine and François, A.R.J. (2005). Interactive multi-scale visualizations of tonal evolution in MuSA.RT Opus 2. Newton Lee (ed.): Special Issue on Music Visualization and Education, ACM Computers in Entertainment, Vol 3 Issue 4 (October), article 3E, 16 pages [ PUB | ABS ]

Chew, Elaine & François, Alexandre R. J. (2003). MuSA.RT - Music on the Spiral Array . Real-Time. In Proceedings of the ACM Multimedia '03 Conference, MM'03, Berkeley, CA, Nov 2-8, 2003. [ ABS | PDF | REF ]

François, A. R. J., Chew, E. (2003). Design for Real-Time Systems. In proceedings for the invited cluster on "OR in the Arts: Applications in Music" at the Institute for Operations Research and the Management Sciences (INFORMS) meeting, Atlanta, GA, October, 2003. [ ABS ]

Chew, Elaine & Alexandre François (2003). Real-Time Music Information Processing. In Proceedings of the 31st International Conference for Computers and Industrial Engineering, ICCIE2003, San Francisco, CA, February 2-4, 2003. [ ABS | PDF | REF ]

reports / posters

IMSC NSF Site Visit 2005: MuSA.RT [ report, poster ] 2004: MuSA.RT [ report, poster ] 2003: MuSA [ report ]

updated July 6, 2010.