>Seeing as how I have built one and it has raised >sensitivty by 19db minimum over driver's suggested >SPL output.
19dB?? Are you sure of that?
For a normal 4th order bandpass system, you can measure the Fb of the system by doing an impedance check and noting the minimum point between the impedance peaks (there should be two). Not sure how you'd go about checking for Fb with this system, but the first step might be to start with graphing its impedance.
