Could someone explain the Lowpass Special/Normal Switch – selects normal (12 dB/octave), or special 36 dB/octave lowpass
crossover for subwoofers requiring a steeper filter curve.
What setting should be used in a particular setup? My system is listed below.

Mains - Klipsch RB5II's
Centers, Front and Rear - Klipsch RC-3II's
Surrounds - Klipsch RS3-II's
Front Effects - Klipsch RB-15's
Sub - Klipsch KSW-12 (waiting for SVS PB1-Plus to come out)
Reciever - Yamaha RX-V3300
DVD Player - Denon DVD-2900
VHS Mitsubishi S-VHS
Sony 36" TV

Thanks for any info.