Hello have me ausm ebay the final stage fetched the following data CLASS-D MONO STRENGTHERS 520W x 1 @ 4 Ohm (< 1.0% THD / 14.4V) 850W x 1 @ 2 Ohm (< 1.0% THD / 14.4V) 1200W x 1 @ 1 Ohm (< 1.0% THD / 14.4V) 1 Ohm stable Full-MOS-FET Class-D amplifier so much my questions : 1, what is the difference between 2 ohm and 4 ohm times apart from the power recording of all URI ;-) there are sound differences or how does it work out of 2, which are woofer recommended for this stage 3, how look t it out if I had to connect a woofer with double vibrating coil a 4 ohm then have to be in the parallel circuit 2 ohm or