| ACE News Archives | ACE News #144 - November 7, 2011 |
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The Solar and Heliospheric Research Group at the University of Michigan is
creating sonic translations of ACE data through a relatively new
technique known as sonification, which allows one to convert data into sound
and hear complex interactions between multiple data parameters. The team was
able to perceive events such as coronal mass ejections, and subtler features
of the solar wind were distinguishable after some training.
Initially, 2-hour averaged solar-wind parameters and charge-state
distributions from SWICS were sonified with a custom algorithm in the Max/MSP
computer-music scripting language. Data points included He++ density and
velocity, average carbon charge state, solar wind type, He/O, and the
prevalence of carbon charge states 4+ 5+ and 6+. In this iteration
http://www.youtube.com/watch?v=n_VyZi0fED4,
the sweeping wind sound is
generated by both He++ density and speed. The speed parameter controls the
cutoff frequency of a band-pass filter, which causes the "whooshing"
noise that sweeps up and down. The use of filtered noise creates a sound
reminiscent of terrestrial wind phenomena. A basic vocal ambience is created
with 3 distinct layers that each correspond to a charge state of carbon. The
prevalence of one charge state over the other, as determined by the
distribution ratio, is used to modulate the loudness of each vocal layer.
Solar wind type is the most readily discernible feature in this sonification.
During a CME, the reverb quickly swells to a much higher volume before slowly
attenuating back to the original volume, which creates the feeling of a sudden
expanse. A Low-Frequency bass tone was generated with a saw-tooth waveform
that traveled algorithmically between a predetermined group of pitches. The
change in pitch happens once every half sidereal Carrington rotation; two
changes in pitch mark one full sidereal Carrington rotation (25.38
days).
Although this sonification effort is still in its early stages, the team has
already successfully utilized auditory data analysis to reveal new insights
into the boundaries between solar wind types. Custom-designed software tools
that enabled researchers to build and vary sonifications in near real time,
much like is currently done with visualizations, could potentially improve
scientific understanding of the data and lead to new ideas for exploration. In
addition to this work, Alexander is currently creating a full orchestral
translation of ACE data as a section of a larger piece entitled The
Quantum Symphony, which will premiere in 2012. This work is in collaboration
with Marty Quinn of the Design Rhythmics Sonification Research Laboratory, and
American Composer Libby Larsen.
This item was contributed by
Robert L. Alexander, Jason A. Gilbert, Enrico
Landi, Susan T. Lepri, Jim M. Raines, and Thomas H. Zurbuchen of the Solar and
Heliospheric Research Group at the University of Michigan.
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Last modified 7 Nov 2011.