SOUND UNITED ANNOUNCES HDMI 2.1 8K UPGRADES TO FLAGSHIP AV COMPONENTS FROM DENON AND MARANTZ SecretsJune 1, 2021 Denon and Marantz Are Also Introducing Two Factory Upgraded Models of the Flagship AVR and AV Processor, the Denon AVR-X8500H“A“ and Marantz AV8805“A“ Press