Denon AVR-1612 Owner's Manual page 41

Connect
6.1-channel (Surround back speaker) connection
If using only one surround back speaker (with a 6.1-channel connection),
connect to the "L" side of the SURR. BACK/FRONT HEIGHT terminal.
For speaker settings in this case, see "When 6.1ch (Surround back
speaker) installed" (vpage 35).
To perform 6.1-channel playback using the surround back speaker,
set "Pre Assign" to "NORMAL" in steps 3 and 4 for "Set up "Pre
Assign"" (vpage 40).
Also use the "Speaker Config." setting (vpage 59) to set
Power amplifier
"S.Back" to "1spkr".
NOTE
L
• A power amplifier (sold separately) is required for this connection.
• For speaker cable connections, see C page 6 "Connecting the
speakers".
• For speaker impedance, see page 36.
IN
L
FL FR
SW
C
SL
SR
SB
38