Believe it or not, “HD Radio” is not the only digital audio broadcast system in the world. Alternatives do exist: one of the most promising is Digital Radio Mondiale (DRM) (which should not be confused with “digital rights management,” a whole other (evil) animal), which has been jointly developed and deployed by some 30 countries around the world. It’s an open-source standard, which has the potential to operate on either new or incumbent spectrum, and contains the potential to practically advance the service terrestrial broadcasting provides; it is not just a “better than analog” standard, featuring chimerical vaporware such as “buy buttons” for the download of digital music – services for which radio was not initially designed.
At present, while Digital Radio Mondiale is gaining traction around the world, it’s all but been ruled out as a potential alternative to HD Radio in the United States, though that may be changing. A coalition of spectrum experts has been formed to advance the notion that broadcasters should be afforded the choice of picking between HD and DRM. As of now, this advocacy is restricted toward the possible deployment of Digital Radio Mondiale on the shortwave and AM bands only; although an FM version of the technology is under development, HD’s relatively slow but steady adoption by U.S. FM broadcasters may make it a tough sell in the marketplace (even though some transmitter manufacturers are making dual-compatible HD/DRM transmitters, and there’s no reason why receiver manufacturers couldn’t follow suit).