<font color='#0000FF'>1. The most common way to increase accuracy in subwoofer design is to make the magnet structure very large (thus creating a lot of force bringing the woofer back to its original position more quickly) and providing it with a huge amplifier and a large voice coil to handle the power. While this is a very effective way, there is also another way. This would be to use a very light, yet sturdy diaphram material in the cone (such as the Aluminum cones that Axiom Audio uses it in all of its mid range and woofer drivers). In mid range and tweeter drivers, the magner size is less important because they are accurate already if you have a lightweight diaphram such as a titanium tweeter, etc. Plus, the weight of a diaphram is lower when it is smaller.
2. Car audio subwoofers CAN make good subwoofers for home, but they typically do not go as deep because they are designed with fs's that are relatively high (because of cabin gain in a car boosting the ~30-20 Hz response greatly). For a driver in the home, I'd STRONGLY urge you to buy from Adire Audio (either their 12" Shiva or their 15" Tempest drivers). While they offer drivers with more displacement and power handling at those sizes, the Brahma and Tumult, respectively, they are less accurate to my knowledge.</font>
