how come you cant hear bass outside?

Hey, you're driving a TRUCK, so if your intention is to impress the sidewalk dwellers or attract chickies with your pounding system, utilize the bed and install external speakers.  Otherwise, to quote a very good friend of mine, "Quit cher bichen."Support the12volt.com

exactamondo!2003 Chevy Avalanche,Eclipse CD7000,Morel Elate 5,Adire Extremis,Alpine PDX-4.150, 15" TC-3000, 2 Alpine PDX-1.1000, 470Amp HO Alt.

I know where your coming from. I want people to hear me coming a block away, the farther away people can hear the bass, the better. I have a Cavalier, so its not much of a problem. But my friend has a Towncar, with his two Memphis 12s in the truck you cant hear a damn thing, inside or outside, so he currently has them residing in the backseat.  It sounds amazing inside, but still not much gets out unles you have all the windows down, and still its not amazing.  I would suggest installing your subs in the bed if you want some bass out side your truck.

One reason why a truck is usually quieter than a car is simple. The amount of metal in the vehicle. A car usually has much more surface area internally and externally that is exposed to the output of sound. These body panels are usually quite a bit larger as well. In the case of a vehicle with a trunk, quite often the pressure build up in the trunk will burp the trunk seal and allow that excess pressure to escape. A truck is built entirely different than a car, it is usually a much sturdier platform that does not resonate as much and has half as much surface area that is directly exposed to the ouput of your audio system, thus the resonation is far less due to the smaller amount of surface area and the greater strength in the panels. I have one customer as well that has 3 12" Concept EX12 subs in the back of his Xtracab Ranger. It is powered by a CCD2400 amplifier. The box is a coupled chamber dual slot loaded design and let me tell you, this thing has some serious output when you are on the inside, but outside she be nice and quiet. 3 layers of Brown Bread for sure but man can that truck spank some serious output.Top Secret, I can tell you but then my wife will kill me.