Procedure

DCA 1824

The DCA 1824 is happy to operate on low impedance loads (450W @ 2Ω) so it is ideal for powering surround arrays that are wired in parallel. See figure below. Alternatively, you can safely bridge two channels together to drive a 4Ω subwoofer (900W @ 4Ω).

 

DCA 1644

The DCA 1644 is not rated to operate in bridge mode on 4Ω and 2Ω loads so don't use it in that mode to drive subwoofers or most LF cabinets of screen speakers. The one interesting exception is to use the DCA1644 to power the on the triple 15" bass cabinet (LF-4315) on the SC-433c or SC-434 loudspeaker. Since each driver is 16Ω, the nominal impedance of the 3 drivers together is ~5.33Ω which the DCA1644 can safely operate.