aiyo... dont blur leh... inside woofer box got manual meh, from there u can get details how they calculate to get 1 ohm 2 ohm 4 ohm 7 ohm etc etc, but this model u can get 1.9 ohm stable this is the best setting for this model. each voice coil is 3 ohm + 3 ohm, if u connect ++ & -- together then u get 1.9ohm. But that amp can support 1 ohm stable so no problem lah.. ur amp safe and ur woofer safe unless u dont follow the right instruction manual.... always read the manual for safety....