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squeak9798

Proper Door Sound Deadening and You

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Here is an excellent and well written article on how to properly deaden and treat your door for components.

 

Text and photos by npdang (aka "cheapboy" on some forums):

 

 

Here's a list of some easy and affordable door treatments that I've found to greatly improve the clarity, as well as the total bass output and low end extension of your mid/bass. If you're using high quality drivers in the doors, proper treatment and install is a must.

 

First thing's first. Make sure to sound deaden your door. This will make the largest difference in reducing annoying rattles. Make sure to do both the inner panel and the outer panel. Use a good 2 or 3 layers. A heat gun or even a hair dryer can be used to soften the deadener up for making it more moldable and easier to apply. Find a good asphalt based mat that is cheap, easy to work with, sticks well under room temperature, and doesn't fall off in extreme heat. I use and recommend Raamat which you can find here: http://www.raamaudio.com/

60 sqft of deadener should be more than enough for 2 doors.

 

As for liquid sound deadeners, I don't use them for a simple reason. They take forever to apply! You would need to clean your door, then apply a single coat. Allow it to dry, then apply another coat. With thick coats and bad weather, it can sometimes take up to a full day to dry between layers. I'd save the liquid deadener for hard to reach places, or for areas where mat doesn't stick easily such as the roof of the cabin or trunk. In my experience, the effectiveness is about the same as a decently thick asphalt based deadener.

 

Also, you can sometimes reduce annoying door mechanism rattles by applying a bit of thick grease to the part.

 

The next thing I like to do is seal up any large holes in the door panel. Doing this very noticeably increases the bass output. I like to use plexiglass since it's somewhat cheap and weatherproof... and also looks nice. It's also much sturdier than trying to stretch sound deadener over a large hole. Cut out a piece that fits your hole, use a bit of silicon, liquid nails, or other thick adhesive/sealant and then slide it in. These panels can be easily removed with a screwdriver worked into the edges if maintenance on the door is needed.

 

Next, I glue a large sheet of egg carton foam behind the speaker location. These do hold water, so you may want to treat it to avoid mold growth. It won't rust your door however, since the foam sits on top of the sound deadener. If you live in a more humid climate, you could use a "Deflex" pad which is sold here: http://www.partsexpress.com/pe/showdetl.cfm?&DID=7&Partnumber=268-242

 

You should notice a slight improvement to your midrange. For me, the egg carton foam was a bit more effective than the Deflex pad.

 

Last but not least, buy ~2lbs of non-hardening modelling clay and a small sheet of 3/4" or 1/2" mdf. Cut a ring or baffle for your speaker to sit on. Place about 5mm tall height of clay on both sides of the ring. Now mount the speaker to one side of the ring, and the ring to your door. Decoupling the speaker from the actual door itself will further reduce vibrations, and clean up your midrange and bass. As an added touch, I like to add a bit more clay around the baffle in order to add weight to the area and further dampen any vibrations.

 

3/4" mdf baffle with non-hardening modelling clay atop.

 

door1.jpg

 

 

Seas Excel w18 with non-hardening modelling clay around the baffle.

 

door2.jpg

door3.jpg

 

 

Notice the plexiglass + liquid nails which was used to cover the hole in the door panel. Also, notice the 3 layers of deadener on the outside door panel through the glass.

 

door4.jpg

 

 

Sheet of egg carton foam behind the speaker.

 

door5.jpg

door8.jpg

 

 

Deflex pad behind the speaker.

 

door7.jpg

 

 

Shot of my trunk lid with asphalt based sound deadener applied.

 

trunk2.jpg

 

 

Shot of my trunk with about a 4mm layer of liquid deadener applied.

 

trunk1.jpg

 

I copy-n-pasted it here since I figured most people would be too lazy to follow a link.

 

Full thread can be found here: http://www.diymobileaudio.com/forum/showthread.php?t=27

 

Enjoy :)

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Nice find!! I'm hoping to sound deaden my car sometime this summer. I can't wait!

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Is this stickied? If not it deserves it. That clay is an awesome idea, and may have to give that a shot.

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I definatly need to finish up my deadening project I started. Got the trunk lid done and the inside of my doors. now to do the skin of the door panel.

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Thank you very much. I'm very close to poping my door panel off, deadening it, and fiberglassing some door pods.

 

Any one here ever tryed the egg carton foam idea, or covered the holes in the door panel?

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Any one here ever tryed the egg carton foam idea,

 

It's sound absorbant material, designed to deflect the rearwave of the speaker to reduce standing waves and cone breakup. That, or deflex pads, are supposed to make a pretty noticeable difference. While I haven't installed any yet, I've read enough about them from IASCA world champions to trust their opinion that they do infact work :) Plus, for the $20 or whatever, you're not out much if it doesn't ;)

 

or covered the holes in the door panel?

 

If you are building sealed doorpods, I wouldn't worry so much about this. It may still help reduce road noise some though. However, if the back of the pod is going to be open into the door (for IB), then covering the holes in the panel is a MUST.

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>>"These do hold water, so you may want to treat it to avoid mold growth."

 

I just put some in my doors. What should I have treated the foam with?? :emb:

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>>"These do hold water, so you may want to treat it to avoid mold growth."

 

I just put some in my doors. What should I have treated the foam with?? :emb:

 

 

I'd check them after a heavy rain and see how bad it is. If you have having major water retention in them, I'd take it out and replace it with weather-resisent foam or use the Deflex pads instead.

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If making custom kick panels would you need to put deadener inside the kick? or one of those deflex pads? or would that not help at all?

 

 

Yes, you should use *something* to reduce resonances. Molding clay in the kickpanel enclosure works very well. Deflex pads may help as well; though, as with anything, results may vary :)

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Thanks, Squeak.

 

Uhmm.. is there really any difference between using eggcrate foam and a deflex pad? For example, I have the entire space behind the 6.5" in the door filled with that eggcrate stuff. Won't it do a better job of blocking sound transmission through the outer skin of the door, or is it really just there to break up the backwave of the speaker??

 

M-T minds are curious..

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Thanks, Squeak.

 

Uhmm.. is there really any difference between using eggcrate foam and a deflex pad? For example, I have the entire space behind the 6.5" in the door filled with that eggcrate stuff. Won't it do a better job of blocking sound transmission through the outer skin of the door, or is it really just there to break up the backwave of the speaker??

 

The material is there more to break up the rearwaves from reflecting back against the speaker, causing distortion. That's why the deflex pads aren't very thick at all, and why they have those ridges all the way around them.....to deflect the rearwave away from reflecting back against the speaker.

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how d u get the egg thing in the door?my car has only a 5.25 hole in the door and i want to use one of the bigg egg cartons.how do i get it in there?

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You'll either have to try squishing it up and shoving it back there, or cutting it into smaller pieces to fit through the hole(s)

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thanks man ima try it this weekend! also would a little caulk put were the speaker bolts to the door get rid of a few rattles?

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I'm going to glue a small bit of 1/2" eggcrate to my car today. Wish me luck. I'll see if I can hear any good results.

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i did the clay thing and saw a big difference. good stuff.

have my deflex pads on the way from PE too :)

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