I don't know of any Active crossovers that will work will high level signals. What you could do is a Passive crossover.
Basically a simple Low Pass filter is just a coil. (1st order 6db/octave)
Use something like this
2-Way Crossover Designer / Calculator
Figure out what the speaker impedance is (2ohm i think) and the desired cutoff frequency... next to your head like that I would say less than 80hz. Then head over to partsexpress and they have a whole selection of crossover building parts.