I have two sub-bass towers with 4 X 12 inch carbon fiber woofers, each. So each set of 4 are wired in series-parallel, resulting in 4 ohms for each tower. There is a master sub-bass controller that connects to an accelerometer on one woofer in each tower, as well as the system line stage preamp. Driving these 8 woofers are two IcePower modules, which are silent, efficient, and very linear for bass info. I chose the IcePower modules and packaged them myself because they were the lowest cost option. I am very happy with them and have Open Baffle main speakers I built that are 95 dB (2.83 V @1m) efficient that I use with this bass system. The background noise level in my audio room is typically 22 dBA (very quiet). The speaker system will effortlessly play peaks over 100 dBA, at the listening position, so it can get as loud as live music. It is a single family home far from neighboring homes, so never a complaint.