Just a few months after it shocked the technology world by signing a technology partnership with “American Idol” while still in private beta, music startup Chromatik is back with more world-beating. Today, the company is announcing $1 million in new investment from Grammy-winning artist Bruno Mars and Virgin Records co-chairman Jeff Ayeroff, among other industry veterans.

Additionally, Chromatik has opened its virtual doors to the public and reveals that it has already onboarded more than 300 organizations to date, including “Idol,” Bruno Mars’ backup band, and the musical departments of UCLA, NYU, and the Los Angeles Unified School District.

Chromatik offers a free iPad app and mobile Web version that modernizes the way musicians of all abilities use sheet music to practice and perform. The platform, which was created by music professionals with intimate appreciation for the actual workflow of performers, replaces paper sheet music with a digitized version that is more organized, flexible, and easily shareable.

“The way we perform and collaborate on music has not fundamentally changed since the days of Bach and Beethoven,” says co-founder and CEO Matt Sandler. “Musicians don’t need another Guitar Hero for real instruments or sheet music gimmick. They need tools that work as hard as they do.”

The application enables users to either upload music or download it from the Web, make annotations and notes, record performance tracks, and then share all of the above fellow students, teachers, bandmates, and friends. Because users can be synced across multiple devices, large bands or ensembles can perform together in perfect harmony.

Today’s launch coincides with a promotion with popular indie rock band Grouplove that awards new users who sign up a full playlist of the band’s sheet music and tablature, including hit singles “Tongue Tied” and “Itchin’ On A Photograph.” Musicians can record themselves and send covers of Grouplove songs directly to the band, from which they will review and select three Chromatik users to give personal feedback.

The latest round of financing brings the company’s total to $2 million, including a $1 million seed round in May from Learn Capital, 500 Startups, Kapor Capital, MuckerLab, Royal Conservatory-Carnegie Hall Foundation’s Dr. Jennifer Snow, its accelerator Launchpad LA, and other angel investors.

The company has not taken any steps to monetize the product, instead preferring to give the Chromatik app away for free and build its audience rapidly. In the future, there are obvious opportunities to offer in-app content downloads, premium features, sponsorships, and music services.

During the beta period, the average user signed in four times per week and spent over 20 minutes per session on the application, the company reports. In total, tens of thousands of hours of play have been powered by the Chromatik platform. Because the way musicians practice and perform has been largely ignored by technology for the last few centuries, Chromatik has been met with rave reviews.

Musicians are an incredibly passionate and loyal customer base to target. Those who adopt Chromatik and find that it improves something they already love are likely to continue being the company’s greatest evangelists. At the rate that the company is collecting superstar users and partners, it shouldn’t take long for the message to spread.