Its first release, the Rio PMP300 digital music player (also known colloquially as simply the "Diamond Rio"), released by Diamond Multimedia in 1998, was one of the earliest notable and commercially successful devices in its category.

Rio was originally a brand of California based Diamond Multimedia.

[2][3] That lawsuit eventually failed,[2] leading the way for the portable digital music industry to take off.

Diamond Multimedia merged with S3 Graphics in 1999 - the resulting company was renamed SONICblue.

[6] On March 21, 2003, SONICblue filed for Chapter 11 bankruptcy protection and then sold off its main product lines; Rio Audio was sold to Japanese firm D&M Holdings,[7] which owned audio brands such as Denon, forming part of their Digital Networks North America subsidiary.