Cardboard drink tray boombox styled by Waterloo audio researcher

Cardboard drink trays from takeout restaurants usually end up in the garbage or recyclingbin.

But acoustical math from a Waterloo audio expertrecently helped create a promotional item that has some sound implications.

At a recent event recentin Toronto, McDonald's restaurants distributed a cardboard cover for the tray, turning it into a smartphoneboombox speaker.

And it was Janelle Resch who fine-tuned the creation to make portable music sound better.

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Resch, a Ph. D candidate at the University of Waterloo and part of the school's Audio Research Group, was brought on by Toronto companyStacklab to help craft the boombox. Itslidesover a drink tray, amplifyingmusic and sound from your smartphone'stiny speakers.

Resch, whose research intobrass instruments such astrombones and trumpetsoften seems abstract and conceptual to people, was able to make complex calculations into the nature of sound and apply them to something portable and practical.

"It was really nice to take the things that I've been studying and learning and apply it to something that I could physically make that other people would use," she said.

Her tweaks included adding a metallic coating inside the cardboard speaker cones to reflect, rather than absorb sound. And her calculationsalso led to the cones being 10 sided, rather thanthan the six originally proposed.

Audible differences

In a field test with CBC K-W, Resch demonstrated how the nature of sound changed when coming from a cellphonealone, compared with one in a drinking glass and one in the drink trayboombox.

When the phone was placed in a glass or mug a trick often used by people to boost thesound the audio is amplified butmuffled by its own reflections.

"It's very echoy:you can hear a lot of the bouncing going around and that's because the cup is cylindrical," Resch explained.

The sound coming from the boombox is clearer.

"The biggest difference is probably the fidelity. This is more clear. You don't hear the same sort of bouncing around of sound [and the mug has] almost a delay," she said.

Resch used an audio spectrogram display to illustrate the difference.

The sound from the glass was louder than the sound from a phone by itself, but not all frequencies were amplified to the same volume. The boombox was louder throughout the entire frequency range.

Way to reach all ages

Resch said she enjoyed partnering up with McDonald's because the boombox would reach many different people.

"It was also really exciting because promoting STEM science, technology, engineering and math for kids, for me, is a very important thing to do. You want to get them interested and everyone, at some point, has heard music," she noted.

"Music, I think, is a great way to get people interested in math especially kids."

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About 1,000 boomboxes were handed out by McDonald's at an event in Toronto in July for the McFlurrydrink anniversary, the company's public relations supervisor Kristen Hunter told CBC News.

"We weren't really sure the type of response it was going to receive, but it was overwhelmingly positive," she said.

The bad news for people hoping to get one: McDonald's Canada has no plans to distribute anymore boomboxes in the near future.

"I don't want to say, 'never say never,' but currently [there are] no plans to distribute any further," Hunter said.