It was easy to find Janice Haworth’s World Music class on Friday morning.

The hum of more than 40 student-made didgeridoos — the centuries-old indigenous Australian wind instrument — filled the music professor’s classroom at Bemidji State University and spilled out into Bangsberg Hall.

Haworth’s students made their didgeridoos out of PVC pipe that they sanded and painted to look like traditional wooden ones. They have no internal mechanisms — the students buzzed their lips against one end of their didgeridoo to produce the instrument’s unmistakable droning sound, punctuated with dingo-like yawps or shifting “e-o-e-o” warbles.

“It’s like a trumpet with no valves,” Haworth said. She brought in a saxophone teacher to help students learn their didgeridoos, which they put together for a broader lesson on the music of the Eastern Hemisphere. Fall semester students made Peruvian pan pipes as they studied Western Hemisphere music.

“This is the first instrument I’ve ever been able to play,” Trevor Poxleitner, a freshman business major at BSU, said with a laugh.

The most participants in a didgeridoo ensemble is 238, according to the Guiness Book of World Records — Haworth joked that her ensemble was only about 200 people short of that mark.