MuSA_RT animates a visual representation of tonal patterns - pitches, chords, key - in music as it is being performed.

MuSA_RT applies music analysis algorithms rooted in Elaine Chew's Spiral Array model of tonality, which also provides the 3D geometry for the visualization space.

MuSA_RT interprets MIDI information received from any Core MIDI source to determine pitch names, maintain shortterm and longterm tonal context trackers, each a Center of Effect (CE), and compute the closest triads (3-note chords) and keys as the music unfolds in performance.

MuSA_RT presents a graphical representations of these tonal entities in context, smoothly rotating the virtual camera to provide an unobstructed view of the current information.

MuSA_RT 1.0 was commissioned by the MuCoaCo Lab as part of the Music on the Spiral Array . Real Time (MuSA.RT) project, and as companion software to the forthcoming Springer ORMS Series book "Mathematical and Computational Modeling of Tonality: Theory and Applications" by Elaine Chew (2014).

The development of MuSA_RT 1.0 was supported in part by the United States National Science Foundation grant no. 0347988.


MIDI input

How do I connect MuSA_RT to my favorite MIDI input device? Open Preferences, select the Input tab, click in the MIDI Input list and select your device.

What if cannot find my device in the MIDI Input list? Check that your device is connected to your and powered up. If Core MIDI knows about it, it should be in the list. If you have just plugged in or powered up your device, just give it a few seconds to register. If you are getting impatient, click on the Scan MIDI Sources button to force an update. (Note that the update should happen automatically.)

What is MuSA_RT's virtual input? It is a virtual Core MIDI destination that MuSA_RT creates and listens to by default. Other Core MIDI applications that act as MIDI sources can send their output to this destination.

Can I use MuSA_RT if I don't have a MIDI input device? Maybe... if you can find another way to send MIDI messages to MuSA_RT. For example, you can use a sequencer to generate MIDI events from MIDI files (and connect the output of the sequencer to MuSA_RT's input or vice-versa). Another solution is to create a Network MIDI Session in Audio MIDI Setup, select this session as MuSA_RT's MIDI input, and invite a Network MIDI device into the session (for example an iPad or iPhone running a MIDI controller App). In any case, you will need some third party elements to generate the MIDI messages.

Why is MuSA_RT not playing the music? MuSA_RT focuses on analyzing the MIDI messages it receives and presenting a dynamic visualization of the result. You must use a third party element (hardware or software) to sound the MIDI messages.


What is the Spiral Array Model of tonality? A geometric model of tonality invented by Elaine Chew. (search for 'Chew Spiral Array' in your favorite engine.)


How do I make triad detection more responsive? In the Preferences - Analysis pane, decrease the time constant value for Triad CE Adapt.