TAS5705 and TAS5706 easily provide a (L+R) mono sum to drive an external subwoofer power amplifier, but it is also possible to reconfigure DAP channels to feed the same mono sum to internal power outputs if that is desired. It is necessary to update 4 registers to accomplish this. The attachment "tas5705-L+R-sum-090929.pdf" explains how this is done.
The revised register codings can be modified easily to use different inputs and outputs.
