Solved! im looking for a subwoofer which is compatible with my sembrant sb750

Solution
Apparently this puppy has 2RCA input, so ideally you are looking for an active (self powered) sub with 8" or large driver, IMO, with the following hookups:

RCA L+R input
Crossover Knob
Gain knob.
RCA L+R Output (after having gone through crossover, send small signal back to soundbar).

So.... TV ---(full range signal)---> SUB ---(high passed signal)----> SB.
Apparently this puppy has 2RCA input, so ideally you are looking for an active (self powered) sub with 8" or large driver, IMO, with the following hookups:

RCA L+R input
Crossover Knob
Gain knob.
RCA L+R Output (after having gone through crossover, send small signal back to soundbar).

So.... TV ---(full range signal)---> SUB ---(high passed signal)----> SB.
 
Solution