Science & Technology

Watch a Beatboxer Inside a Real-Time MRI Machine

Plenty of people can mimic sounds with their mouths. Beatboxers, however, take it to a whole other level, realistically producing every bass beat, snare hit, record scratch, and melody line in a single track, all with their voices. They're the "one-man bands" of the 21st century. A research team from the University of Southern California (USC) wanted to know how they do what they do, and in the process, took some jaw-dropping footage of their vocal tracts in action.

The Human Instrument

Beatboxing might sound like an odd thing for scientists to research, but it actually has the potential to solve a lot of deep mysteries. For USC's Speech Production and Articulation Knowledge Group (SPAN), led by Professor Shri Narayanan, it held promise for three questions in particular.

First of all, because beatboxing uses the same toolbox as language — the tongue, the larynx, and so on — but not the same words, it might help us better understand how human communication starts as a mental representation and becomes a produced sound. By looking at multiple beatboxers, the team could also study whether people tend to use different approaches to creating the same sounds. And finally, because beatboxing is so new, researchers can use it to study how people learn to use their vocal equipment. That could one day help people speak again after losing the ability because of injury or disease.

Starting in 2006, the team began putting experienced beatboxers in a real-time MRI machine so they could watch what happens inside the beatboxer's mouth and vocal tract as they perform. They began with one beatboxer and one opera singer, and over the years they've had the chance to look at five different beatboxers of various experience levels.

Real-Time MRI of a Beatboxer From 2013

This was quite a technological feat: The machine scanned the musicians at a whopping 83 frames per second while an audio recording captured the sounds they made. That required some advanced noise cancellation, according to Timothy Greer, a Ph.D. student in computer science and a researcher on the team.

"That was done because the inside of this scanner board sounds like a jackhammer," Greer told Curiosity. "It's really hard to hear what the beatboxer is doing as that sound is going on."

Real-Time MRI of a Beatboxer From 2017

Looking Inside

So, what have they found? It turns out that, perhaps unsurprisingly, beatboxers create a lot of the same sounds you find in human language — but they also create some sounds you won't find anywhere. One sound that's common to both language and beatboxing is what linguists call an "ejective," a sort of popping consonant produced when both the mouth and the vocal folds cut off air flow, and the larynx rises to push air through the vocal closure. These sounds are commonly found in Native American and African languages, and not so much in English (although they pop up from time to time). In beatboxing, ejectives create the sounds of kick drums, hi-hats, and other explosive effects.

"But we also observe that some beatboxers make sounds that you don't find in language at all," said Reed Blaylock, a Ph.D. student in linguistics and researcher on the project. One of those sounds is what's known as the "inward K," which beatboxers produce by breathing in while making a "crisp, percussive sound" (you can hear an example in the clip below). Breathing in to produce certain sounds helps beatboxers keep the beat going without stopping to take a breath.

"That kind of sound doesn't exist in language," Blaylock told Curiosity. "There are a few other ones, too, where the sound that a beatboxer uses uses some pattern of coordination, some breathing style, or some other type of closure that we haven't observed in any language so far."

"Rimshot K" Sound

The team also found that any two beatboxers might make the same sound in different ways, especially if one is more experienced than the other. Here, again, ejectives played a prominent role. "It seemed that the advanced beatboxers had a better, more controlled use of ejectives," said Nimisha Patil, a former undergraduate research assistant on the project and a beatboxer in her own right.

The discoveries the team has already made suggest there's exciting potential in beatboxing as a way to not only answer scientific questions but also to give beatboxers and vocalists a novel glimpse into their art form and give doctors and clinicians new ways to help their patients. To see more of their work, check out their website where you can compare and contrast different beatboxing sounds.

"It kind of takes the mystery out of what people do inside the mouth, which is like amazing," Narayanan told Curiosity. "It's a vocal dance that you can see."

These videos are from a research project being conducted at the Signal Analysis and Interpretation Laboratory (sail.usc.edu/span) at the University of Southern California by Professor Shri Narayanan and his team with support from the NIH and NSF.

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Want to learn to beatbox? Check out "Beatbox Complete," a method book by Andreas Kuch and Indra Tedjasukmana. We handpick reading recommendations we think you may like. If you choose to make a purchase, Curiosity will get a share of the sale.

Written by Ashley Hamer November 20, 2018

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