The motion-capture camera tracks a band of pink tape on the player’s index finger. Credit: Jack Long | Special Projects Director

Nick Shea, a doctoral candidate in music theory, asked Jason Buchea to pick up the electric guitar and get comfortable.

As Buchea sat down and started picking at the strings, Shea grabbed a roll of pink tape that was sitting in the corner of the dimly lit soundbooth at the Ohio State Cognitive and Systematic Musicology Lab. 

“This is the motion-capture rig, so there’s a little camera here,” Shea said as he cut off a piece of tape. “It’s going to track the color pink on your index finger.”

Buchea, professional guitarist and a graduate associate in musicology, is a participant in Shea’s research, which focuses on investigating how an instrument influences a player’s performance, how they compose music and their musical phrasing choices. 

Shea said musicians often make small movements on the fretboard while playing a musical phrase, but shift a larger distance when they move in between phrases. 

A musical phrase can be thought of like a grammatical phrase, where a complete thought is stated as part of a larger structure.

His research is also demonstrating that classical music theory cannot entirely explain the characteristics of modern music.

Shea’s research is offering a new way to classify the musical choices performers are making by explaining melody and chord selections through the way the instrument is played, Anna Gawboy, Shea’s dissertation co-adviser and an associate professor of music theory, said.

“They are actually performing a type of knowledge through their instrument that we can study and we can say is absolutely essential to the way that the music sounds,” she said.

The camera device is small — a black action camera bolted to a metal brace, which is attached to a red Squier electric guitar.

Buchea wrapped the tape around his finger so the camera could track his hand as it moved around the fretboard. Shea said a computer program would then estimate the distance his hand travels.

Shea told Buchea he needed to play a series of musical chords four times: two times at a slow tempo in both a rock and pop style, and twice more in each style at a moderate tempo.

Shea handed Buchea headphones so he could hear the synthesized drumbeat, and Shea closed the booth’s door.

Buchea set about constructing an impromptu riff to fit the chords and style.

Part of Shea’s research is looking at how professional players use their instruments to create and understand music. But Shea said he is also looking at players with little or no formal music training.

“Musical theorists talk about musical understanding in terms of chords and chord relationships most often,” Shea said. “Performers who maybe don’t have that kind of training that music theorists have still have a very intuitive and sort of performative understanding of form.”

Growing up in rural Missouri, Shea started teaching himself to play the electric bass. He said he didn’t have consistent access to music education, so through his guitar, he got a grounding in the fundamentals of music.

“My way into music theory was actually through the fretboard of my electric bass,” he said. “I understood intervals as shapes on the bass. I understood chords as shapes on the bass.”

Gawboy said Shea is validating the experience of performing musicians through his research.

Modern styles of music, such as pop and rock, are often analyzed by music theorists through western classical descriptions, she said. But modern styles can’t always be explained that way, just like German can’t be explained using only English grammar.

Shea said the motion-capture experiments are just one piece of his continuing research that started four years ago.

Shea said he started by analyzing the guitar tablatures — a way to write music using diagrams of finger placement instead of a traditional staff of notes — of popular pop and rock songs. 

“You just have to have a pretty decent ear for rhythm, and then you’re given basically the coordinates to play the notes on the fretboard,” he said.

The analysis showed that there is an association between how a player’s hand moves on the guitar and the musical form and harmony of their compositions, Gawboy said.

From the analysis and motion-capture experiments, Shea said he has noticed performers moving around the fretboard very little during a musical phrase. But when the performer moves between two phrases, such as a verse and chorus, they are more likely to move a larger distance.

Gawboy said the performers’ movements are deliberate.

“They’re not necessarily thinking about an abstract realm of chords, where they’re putting chords together because they know it makes sense,” she said. “They’re feeling these chords on their instrument, and they’re playing, and they’re using their own selves as kind of this internal feedback to make compositional decisions.”