If what you want to do is actual active bi-amping, this would fall into the category of "if you have to ask how to do it, don't do it". It undoubtedly would improve the sound of your speakers, possibly to a large degree, but it is not something that you attempt without the necessary measurement equipment and knowledge about electronics and acoustics and how they relate to speaker design. You would need to quantify the design of the original passive crossover network in electro/acoustical terms and duplicate that with an active crossover network. Addtionally, all speaker systems are "voiced" by their manufacturers to achieve the sound they desire from the drivers - this would have to be duplicated by electronic eequalization. There may also be phase/time compensation in the passive crossover network that would need to be taken into consideration. If you wanted to change the voicing / phase or any other parameter, you would need to know how to achieve this with active electronics.