Meridian Audio 568 - Manual (Page 114)

Troubleshooting
107
When playing a Dolby Digital DVD, the
568 selects the Pro Logic preset
DVDs include a two-channel Dolby Digital soundtrack, which will
use the default two-channel preset.
❍ Select a six-channel soundtrack, if it is available.
Unit is overheating
If there is not adequate ventilation around the unit, or you are
operating it in an enclosed space, you will need to fit the
optional Fan kit.