Harman Kardon AVR20 II Owner's Manual page 12

17
When you drive the front speakers with another amplifier
(Remove PRE-OUT/MAIN IN jumpers when the front speakers are connected to external amplifier.)
CENTER
SPEAKER
FRONT CENTER REAR
PREOUT MAININ PREQUT PREQUT
DOO®
® RIGHT rs © LEFT ®
FRONT SPEAKERS
AIGHT LEFT
8Q Bt
FRONT (left)
FRONT (right)