So, no high pass filter is a brick wall. If your 2-way is sealed, and you add a 2nd order filter you end up with a total 4th order. Pretty steep, 24dB/octave.
That is how THX attempts to do things, with 80 Hz satellites, and a matching 24dB/octave lp on the subwoofer.
The best way to do this is before your amp. Either using a miniDSP type of solution, or an analog system like Bryston's crossover. The advantage of the miniDSP route is unlimited EQ and time delay being available at both high and low pass.