Sound United, parent company to Denon, Polk Audio, Marantz, Definitive Technology, Classé, and Boston Acoustics, is teaming up with digital music distribution/management service Roon to bring Roon Tested Accreditation to 68 Denon and Marantz AVRs, amps, preamps, SACD/CD players and other devices enabling seamless easy-to-use…