Music and science, an unlikely match

CNU’s Dr. Tfirn begins research surrounding the science of sonification

For centuries, scientists have used visual mediums in order to transform sets of data into bar graphs, line graphs, chart graphs, etc. More recently, scientists have been using a different method called sonification to represent numerical data. Sonification is the process of turning numerical data into sound. This is done by using special software that assigns data values a pitch, rhythm, dynamics (amplitude) and a tone (type of sound). For example, Brian Foo, a data artist from New York City, coded a piece of music which showed the median income inequality in the neighborhoods of New York along a major metro path. As the median income of each area is increased, the dynamics of the piece increased with it. Turning this data into music makes it easier for people to understand what the data signifies. 

Here at CNU, Director of Composition and Creative Studies, Dr. Maxwell Tfirn, is working alongside Dr. Rosanne Ford and her assistant, Rhea Braun from UVA, in sonification research. They have been using colonies of HCB1 E. coli and exposing them to chemicals to observe their chemotaxis, that is, the movement of the cells as a result of chemical stimuli, by exposing the cultures to certain chemoattractants. They use microscopes to record the movements of the bacteria under a microscope and use special software for the sonification of the data. The videos of the bacteria are created at UVA, but the sonification occurs at CNU. Dr. Tfirn has written a special program for this research that handles the sonification. 

The camera records the movement of the bacteria along the focal point of the microscope. The focal point is the place where the lenses focus. When a cell passes the focal point, the cell becomes out of focus and cannot be seen under the microscope. 

As the bacteria move towards the chemical, they move their flagella. Flagella are tail like structures that allow cells to propel themselves forward. As they move, they cross the focal point in a circular motion, causing them to appear and disappear under the microscope. These actions are recorded and fed to the sonification software.

Basically, the software looks at how many times the bacteria cycle through the focal point over time. As the bacteria move faster, they cycle more frequently, while when they move slower, they cycle less frequently. The frequency of the audio gets higher as the density of cells cycling increases. 

These cycles of movement are heard as a grain of sound. Using sonification to observe the chemotaxis of the E.coli allows scientists to listen to how they move, which cannot be done with visuals alone. The sonification of the data makes their movements audible. 

However, studying the E.coli cultures is not the main purpose of this research. Dr. Tfirn’s goal is to create the auditory representation of the data live as the cultures are being recorded. This process requires a lot of computing power which is why he has ordered a powerful computer that will be able to conduct the sonification live. Being able to turn the data to sound as the experiment is occurring would open a new world of possibilities in regard to sonification. Currently, many experiments require the data to be obtained before the software can convert the it to sound; however, there are many instances in which having the auditory data instantaneously would be beneficial.

~Cesar Gonzales-Engelhard, Staff Writer~


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