quotes...
"Bass blockers are just passive highpass crossovers of different alignments, usually just capacitors that roll off at 6db per octave. This kind can crossover at many different frequencies, depending on the capacitor value and the speaker impedance. They should only cost you a couple bucks each, but they dont do a very good job, IMO." Nathan Munson @ Carsound.com forum, Store Owner
"Good luck trying to get those bass blockers to work properly. They almost never do the job accurately because speaker impedance varies with frequency and it's really a shot in the dark getting the right bass blocker. I suggest you bite the bullit and get yourself an amp with adjustable high pass filter. .. cont...
The value of the capacitor chosen is linked to the speakers supposed "nominal" impedance. The problem is that at say 100 hz, your speaker's impedance may be several ohms away from it's "nominal" rating of 4 ohms or 8 ohms or whatever silly value they try to pass off as a guesstimate. I think David Navone defines "nominal" as "not in reality" which I feel is a good definition." Evelyn JW. @ Carsound.com, Musician/Recording Artist/Installer/Tech
There is a right way and a fundamentally incorrect way. Using "bass-blockers" is the wrong way to go about crossing over speaker drivers. The quality of the components in a passive OR active crossover network is what is going to determine the accuracy of the effective crossover range and the order or slope of the cut-off... 6-12-18 or 24 dB. Quality matters.
I do agree that a Zobel type crossover would be great, question is, can you afford it and secondly, reaccess your "sound" goals and determine if those 3.5" drivers are really worth working with...as opposed to say a good pair of coaxials in a kick-pod location.