I have two Linear compression 12's each of them is in a three cubit foot box with two 4 x 15" ports. I have them in a buick park avenue and they are extremely loud. Loud to the point where you can yell and not here yourself or anyone. If you put them in an even smaller car, they will be even louder. I dont even have them in the biggest box yet. That is my new project. I am only pushing 1200 watts to each of them at 1 ohm. I hear the 10's are just as loud.