Editing Sound Deadening (section)

===Intro===

I have recently finished sound deadening the doors on the Skyline.  Since I've done this before I'm not surprised with the improvement but if you haven't done it before you WILL be surprised.

Some people don't like to sound deaden their doors thinking that they dont need to. WRONG. Put simply to seal and sound deaden your door provides the best bang for buck upgrade that can be had for your audio system.

OK, a little of information before we get into what's involved. If you don't want to read this then feel free to scroll ahead.

Basically this process aims at achieving two things.

* 1) Sound deadening door panels will reduce the road noise and the rattles caused by those big ass drivers in your doors.

* 2) Sealing your door creates an enclosure for your drivers.  Basically we are using the door cavity as a box!!

Sound deadening doors simply aims at adding mass to the door panel in order to reduce the resonant frequency of the door panel.  What happens is that the high and low pressure that your speaker makes in the air causes the door skin to move in and out, just like another speaker!! This is bad since this causes more noise through rattles and the like. Solution, add more mass!!

Secondly the sound deadening helps reduce the transmission of road noise through the door skins. This is achieved simply by adding more material to the door.

Thirdly by sealing your doors then effectively what we are doing is building a box for your drivers.  This has two advantages.

* 1) The air does not escape from the door.  This means the backwave from the speaker doesn't leak into the cabin. This means that your driver can produce louder and 'punchier' bass.

* 2) This is a very minor point but by sealing the door we can use the pressurised door cavity as suspension for your cone, adding more cone control. but this is pretty insignificant unlike a sub box.

OK for those who want to read a bit more on how to reduce noise read this link:

http://www.grc.nasa.gov/WWW/AcousticalTest/Industrial/Vibration_Control.html

Pretty much simplified version of what occurs.