@mogsailor

RE; LF termination

If that "helper-woofer" circuit only has a single inline ( series ) inductor-coil on it > then you're good-to-go with leaving it un-terminated.

OTOH, if there's a capacitor following the inductor placed across the two wires then you should terminate those two wires with something like a 40 watt resistive load .
- I think the helper woofer was actually 4 ohms to help keep-up with the rest of the system > therefore 4 paralleled 16ohm ( 10 watt ) resistors would fit the bill.