If I understand it well, there are at least four factors in mutual relation when building a subwoofer: 1) Size 2) Power 3) Eficiency 4) Amplifier Flatness Add to this the values of the driver and you can build anything you want, right? Of all those factors, I think the weaker part is the number 4. How can we know the response of an amplifier BEFORE making a sub for it? Another question, I understand one have to compromise at least one of the three first factors. If the other two remain the same, will alter just one of them will give (automatically) better results? For example, if I have a sub driven by a 100 watts amplifier and just add a 200 watts one, (asuming of course that the driver will support that power) I have a better sub? Or if I just double or quadruple the inside volume, will I have a better sub?