would suggest against using fiber glass and then placing it in bags. i have personally done it and it is a complete pain in the ***. Its difficult to get all of the air out of the bags and they get caught on the window as it travels down and if water gets in you will have mold growing. I personally haven't used this product but it has the same exact acoustical properties as fiberglass, you just dont have to put it in a bag, it comes with an adhesive backing and its not flammable.
Check it out here
Create a Quiet Home with Safe
Like was previously stated though, before you start worrying about absorbing the back wave of the speaker, make sure the door is properly sealed and deadened first, because that will net you the bigest results.
CDT carbon fiber 6.5" mids & DD T2 tweeters on a Polk Audio PA D4000.4
SP4 15 w/ Tantric SHD softies on a DC 5.0k
2 runs Monster Cable 1/0, SounDrive rca's, Singer 310a 6 phase, Exide G78 under hood XSD3100 rear, plenty of deadener
hmmm, judging from that picture, and again this is just judging from a picture. It looks like you
should be able to remove the shinny steel looking metal rectangles. I would try and remove them
so you can gain access to the outer layer of the door. If you can gain access to the outer layer
the first thing I would do is apply a layer of CLD tile type sound deadener. Here is an example of
what im talking about
From there you have to decide if you want to use a sound deadener to absorb the backwave of
the speaker. Absorbing the back wave of the speaker stops it from building up inside the door
panel, creating standing waves and pushing back on the speaker cone resulting in distortion and a
loss of mid bass performance. If you choose to do this I would not use pollyfill. If you use pollyfill
you will have to encase it in some type of a bag so it doesn't hold water inside of your doors and
grow mold and quickly rust your door pannels. Fiberglass also holds water and does the same thing
enless you place it in some type of a bag, but Fiberglass is much better at absorbing the sound
waves. The product I recomended for this is Roxul's safe N sound. It has the same properties as
fiberglass and will absorb the backwave just as well, like I previously said though there is no need
to place it in bags because it will not grow mold or hold water, it also comes stuck to an adhesive
tape which makes it easy to apply. If you choose to do this step do it after placing down a layer of
If you choose not to do the backwave absorbent deadener such as fiberglass or roxul safe N sound
Go ahead and apply a layer of CLD tiles to the inner door pannel (the part of the door you can see
in your picture) If you choose to apply the fiberglass or foxul safe N sound you must do that first
before applying the CLD tiles to the inner door pannel.
Since you're buying a head unit, then I would say right away that Pioneer DEH-80PRS is better. As for speakers. I heard that cheaper Focals do not always sound good, specially the tweeters may require some additional taming (and this is what you need good DSP for). Have you heard about JBLs MS-62C speakers? They have been getting very good reviews recently.
@av83 ; @itsblown ; @zako ;
Thanks for all the help guys. Last night I went to Home Depot and bought so rubber/foam weather stripping, and just went around and around the metal door until it was built up enough to form a seal between the door and plastic bracket. I would say it's 97.7342856% air tight. Also, when I took off the woofer, I was surprised at what I found (I had put them on a year ago and never paid attention to what was behind it). Here is a picture that will do most of the explaining. I just used a little bit of polyfill and stuffed it around the cracks to the left and right of the circle, and spray glued a thin circle piece in the center. I only got one door done last night, and it was a pretty hack/unpretty job, but hey, it's sealed... sorta. I'll take pics and put them up today.
EDIT: Added picture
polly fill is going to hold water grow mold and quickly rust your door pannel, like I previously said. I really dont suggest you put it in the door pannel
being concerned with the rear wave is why we seal doors, putting absorption in there is the next logical step.
just think about home audio tower speaker enclosures - how many are made of sheet metal and are hollow? none.
good speaker enclosures try to be as dense as possible and use absorption inside the enclosure to prevent the rear wave from coming back out the through the cone. it's not a new idea to audio, just difficult to execute in a car.
we use Basalt Rock insulation in generator exhaust systems due to the high thermal capability of the material. it's better than nothing, but not even close to fiberglass batt. plus, while it is not an organic material (neither is fiberglass) it can still trap water which when combined with dirt creates a place for mold. you want to avoid anything fibrous in nature in a door. that is why you need to protect it with plastic. when installed on the outer door skin, and enclosed in a plastic bag - there are no worries with water or mold.
if you're serious about making a car door sound good, you need to be serious about putting absorption in there - and something that actually absorbs lower midrange frequencies requires a lot of surface area and good absorption coefficients.
have you been helped by me? i'd love to know. got a question? shoot me a PM.
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@av83 ; @itsblown ;
Just an update. After doing the work I feel like snare drum hits and things around that frequency are MUCH better, as in clearer and more powerful. Although this is awesome and improves my listening experience, I was hoping it would improve things that were lower frequencies than that. Maybe it has to do with how little airspace there is behind the woofers. Or I feel like it may have more to do with my substage though. Without adding 8" (or maybe 6.5") midbass or subs to the doors I dont think I'll get what I'm looking for. There is a nice place I could add some into the door down by my feet, but it would require cutting out a circle in the door panel and doing quite a bit of custom work. Not to mention I dont have the money to do anything like that (but I do have the time... being a senior in high school is the easiest thing in the world). Perhaps I could also get what I'm looking for by getting a custom box that is tuned differently and more suited towards SQ rather than SPL... but I dont really have an SQ oriented sub in the first place. What my dream is, is to get that "2x4 to the chest" type of kick out of kick drums, etc. But I also want to be able to blast the rap and shake the shit out of my passengers. Not exactly sure how to go about doing that, or if what I want to do is possible. I guess what I'm looking for is SQL. Which is expensive and hard to do right. What do guys think? Is a custom box (and maybe new sub) the way to go? Or would it be better to put in some more speakers or subs in the doors? I dont plan to do either anytime soon.
Glad to hear youre improvement helped. if you add the CLD tile deadener and Fiberglass bags or roxul safe n sound to your doors it will increase mid bass performance out of your door speakers. Honestly I hate to say it but on the sub stage you may be better off starting over. I would try and sell your stuff on craislist and look into a better amp and sub and a custom box. Most important thing is box but I think even by building a custom box for your sub 500 watts isnt really going to help you out.