[brucek]

The answer depends on the situation.

If you are using two subwoofers and they require differing equalization, then you split the signal feeding the BFD and connect the two subwoofers to the two BFD outputs. This allows the two BFD channels to be used independently.

If you are using two subwoofers and they will be using the same equalization then you can feed one channel of the BFD and split that output BFD channel to the two subwoofers.

If you are using one subwoofer, just use one channel on the BFD fed to one channel of the subwoofer amplifier.

brucek