Editing Sound Deadening (section)

==Deadening Doors==

===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.

===OK ONTO THE SOUND DEADENING===

What you will need:
*Sound deadening; this comes in a mat, spray can or paint on version. always go for the mat because you can put a lot more weight on the door than you can with the paint on stuff.  The draw back is that it 'seems' way more expensive. I always try to convince people to hold up a can of spray on and feel the weight.  Then pick up your sound deadening mat and feel the weight.  That difference is significant.  It's always cheaper to use sound deadening mat to do the job.

:Brands to look for; Stinger Roadkill and Dynamat both make very high quality stuff but you have to pay for it.

:I myself use some stuff called DFQ Ultra (pm me if you want some) which is much better value for money.

:You can also get other brands but remember you get what you pay for.  A lot of cheap stuff doesn't stick well and will fall off in no time flat.

*Grease Remover: Turpentine is a bit harsh and will strip the paint pretty easily, but then again this isn't a real problem because your gonna sound deaden over the exposed metal anyway. If you're worried about rust then use some specialist grease remover. It's just watered down turps anyway.
                       
*Heat Gun: It is very important to use a heat gun to heat the mat so that it becomes more flexible and also so that you 'activate' the glue.  This is a MUST do.  A blow dryer suffices.

In this tutorial I am going to call the two door skins the inner skin and the outer skin.  The inner skin is the door skin that is closest to the interior.  The outer skin is the skin you can see from outside the vehicle.

OK so the process:

* Step 1) Remove the door trim. If you dont know how [[Door trim -Removal|LOOK IT UP IN THE TECH INFO SECTION OF THIS SITE!!!]]

* Step 2) Remove the grease and dirt from the door skin.  This is going to take you a fair while to do.  Please please ensure you clean it very well since no sound deadener will stick to your door if it's covered in shit.  What I do is first remove most of the big bits of dirt from the door with a rag soaked in turps.  Then when it looks really clean, I scrub the door again with turps and a clean rag just to make sure.

* Step 3) Apply the sound deadener to the outer skin.  To do this simply cut out a small bit of deadener and heat the material up.  Then pull some of the backing off so the sticky bit is exposed and stick that to your door.  Rub it onto the metal really hard making sure that you rub ALL of the material.  If your hand doesnt hurt after 5 minutes you ain't doing it properly.

:For best results add two layers over the area behind the speaker.  Then deaden the side intrusion bar.  This is the raised strip of metal that runs along the length of your outer door skin about half way up the door (it's about 200mm wide) this always rattles so it's best to deaden it.  It is up to you whether you deaden the rest of the outer door skin.  It doesn't cotribute to lowering the noise floor but it will keep the sound in your vehicle so you dont look like a wanker when you have your music cranked.

* Step 4) See all those lovely control rods for your handle and locks??  They LOVE to rattle.  Best way of preventing them from rattling is to run over to your local foam and rubber shop and buy some rubber pipe.  Try to find some stuff that is real flexible and has a pretty thin wall.  Then all you have to do is slide the pipe over the rod.

* Step 5) Apply the deadener to your inner door skin.  Do the same as before however this time you want to cover all the metal of the door skin.  This is where you will kill most of the road noise so do it well!!!  BUT don't deaden over the really large inspection holes or over your control rods.  We will get to the inspection holes next.

* Step 6) Seal the door.  This is straight forward.  Cut out some bits of MDF or whatever material you have lying around that is nice and stiff.  Add a layer of sound deadening over it.  Then stuff it into the hole in the door and simply duct tape it into place.  By duct taping it into place you can remove it later.  Use LOTS of duct tape.

* Step 7) Sound deaden your door trim!!  This loves to rattle so it can't hurt to add some deadener to that as well.

* Step Cool) Grab a beer you need one for motivation.  Coz there is another door you have to do yet!!!



Here's a pic of my front door:

[[Image:Sdead_6.jpg]]

So there you have it.  Some nice solid sound deadened doors!! - '''SCorpion'''