I'm using the old HSU 12Va subwoofers powered by a Crown K1 bridged. I agree with the comment above about blending the sub to the woofer driver of the main speaker. I'm using a pair of BG 520dx ribbon speakers which have a pair of 6.5" mid-woofer drivers per speaker. The 6.5" mid-woofer provides super quick mid and upper bass response, but zero low end extension past 60Hz (in room response). To create a seemless main / sub combination I placed the sub in the room null and the main in ta room peak. I ran the main speakers at full range to take advantage of the room reinforcement and crossed the sub 10Hz above the in-room -10db roll off. This set up used peak and null out of phase information to cancel out a lot of the room frequency problems without the aid of using a eq. Placing the sub in the null provided the same razor tight bass response of the BG mid-woofer without the loss of extension or low to mid bass impact and foundation (I tuned the placement running full range material through the sub with the mains turned off). The tuning method aloud me to mimic the mid and upper bass response of the main speakers, now the main speakers and sub are completely seemless.
Alan
