A guitarist strums alone. Across the city, a drummer keeps time, while across the country, a singer croons. These aren’t lonely soloists. They’re a band, and this is a recording session.

A new web app called Nebulus lets musicians collaboratively record and mix their own tracks, all online, simultaneously, for free. “It’s not been done before,” says Robert Kotcher, co-founder and CEO of Nebulus Audio. Kotcher, a strings player and computer science graduate student at Carnegie Mellon University, gathered four musical friends and founded the company in March 2014. With help from the AlphaLab startup accelerator, they launched the Nebulus cloud-based app in late August.

Nebulus users upload sound files, or record new ones through their computer’s microphone, and layer them together with fellow artists. Don’t have a band? “We’re building a social platform to help musicians find others to collaborate with,” says Kotcher.

“It could be a game-changer,” says Lance LaDuke, lecturer of music business and coordinator of special and creative projects at the CMU School of Music. At an early software demonstration, LaDuke saw that though Nebulus lacks some features of existing music software, it lowers the barrier to entry for new musicians. “I’m super excited about it for myself,” says LaDuke, an accomplished brass player.

LaDuke is judging a monthly Nebulus competition. Artists producing the best 30-second songs with the app win cash—the more collaborators, the bigger the prize. “We want to get people excited not only about recording themselves, but their bands, too,”says Kotcher.

At a week old, and with only word-of-mouth advertising, Nebulus already has dozens of users. Though Nebulus can connect musicians worldwide, Kotcher thinks it was born in the right place: “Pittsburgh has so many talented people in music and tech, we felt like we have a lot of opportunities here.”