Very true, although it depends on the disc in question. The original Dolby EX-flagged discs would drop out if the sixth channel was disabled but would work in Dolby 5.1 if the speaker was enabled. Later discs (which includes the Lord of the Rings movies) used a different Dolby flag, and those go one step farther - forcing the EX mode (or the proprietary equivalent, such as the 1050's 6.1 Surround) to be used.