If you use a passive woofer filter, you will probably want to use a Zobel damper. Please see page 37 of the crossover document on my website for more information about this device. You can see the response of a woofer/crossover subsystem with no damper on page 46, and the same woofer/crossover subsystem when a damper is installed on page 49. That will give you an idea why I suggest that this mechanism is probably something you will find attractive for your speakers. This particular example uses a second order woofer filter, but you will find that second and third order filters act in the same way, where peaking is concerned.