Sound Control Solution
An optimal speaker enclosure is made of a solid, non-resonant material that minimizes internal reflections (back-wave noise and distortion). As you can see from the picture, a non-treated door is far from ideal. With the right materials and techniques, you can restore the lost sound quality of your door speakers and lower the overall road noise inside your vehicle. When your vehicle is quieter, you no longer need to turn up your stereo to overcome the road noise. A 3dB increase in dynamic range is equivalent to doubling your stereo system’s amplifier power.

In your car door, you are dealing with three types of noise: vibrational, airborne and reflective. The vibrational part is obvious. The midbass output from your door speakers causes buzzes and rattles of the door sheet metal and the door panel itself.  Airborne noise comes from two sources. The outside road noise and the back-wave speaker output come through the holes in the inner door skin. The speaker’s back-wave noise is particularly bad because it not only colours the sound, but also cancels the bass output. The final problem is reflective: sound bouncing around where it shouldn’t. This happens in two locations. First, the back-wave sound from the speaker reflects (bounces) off the outer door skin. This sound interferes with the speaker and makes the speaker sound like it is playing through a tube. The second area is between the inner door skin and the decorative door panel. Sound bounces between them and gives it a reverb type of sound. The guys at Dynamat have developed a Good, Better, and Best solution to deal with these problems.