10 sq. ft sound deadener between 2 doors. HELP!

[tniemuth95]

Hey guys I was gifted 10 sq. ft of sound deadener by a friend who had it left over from a build. I know it wouldn't be very expensive to just buy more but money is super tight being a college student. I'm trying to make it stretch between 2 doors. The car is a 1998 Chevy 1500 Silverado. According to my other forums it takes 8 sq. ft per door, per panel. I want to make it sound as good as possible with 10 sq. ft between both front doors. My options

1. Cut into strips and space evenly across inner door panel.

2. Place around speaker on inner door panel and behind speaker on outer door panel.

I'm kind of leaning towards spacing it evenly across the inner door panel as I think that will give me the best sound improvement and resonance reduction but I could be wrong.

The speakers are Alpine SPR-60 coaxials running off a 100 watt rmsx4 amp. They already have a 1/2" mdf baffle mounted under them.

Thanks guys. Any help is appreciated!

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[keep_hope_alive Premium Member]

cut into squares of varying sizes. place on the various surfaces in a non-uniform arrangement. symmetry is bad for acoustics.

rap on the metal with your knuckles and listen for how long the resulting sound "rings". you want to treat the doors such that the resulting sound decays quickly. rap on all areas of the door and add pieces as needed.

also see my budget door treatment using fiberglass insulation and PVC drop cloth in my build logs.

 

[Chromatic]

keep_hope_alive is on the money with this.. I haven't dealt with deadening doors in a car yet (but I'm about to).. but I have done it many times for studios for recording, or just rehearsal/practice with my band,.. And it's definitely not about looking 'pretty'.. it's about testing each area of the area you are covering and applying as needed to resolve the accoustics for that say.. 5x5 area of the door.

So I'd first knock around on the door with the interior panel on.. (if it's still on).. and make a note (or even draw a quick sketch) of what areas sound hollow, or otherwise not solid. Then do what KHA suggested.. with the panel off knock on the panel all over and where it echos or otherwise sounds hollow, or not as solid as other spots.. apply a small square/strip in that area (sometimes you need to apply it further in the door through the holes you can get access to.. (but be mindful of the window movement),.. and other areas you want to apply on the "middle" of the door which is the outer of the sheetmetal exposed when you pull the door panel off.

You have limited amount of material to work with, but 10 sq. ft. should really be plenty to get both doors done. Just take your time, be patient. Perhaps, don't use it all the first go around. But the panels back on after you've used say half or 3/4th's of it. See what it sounds like.. then pull them back off and add more where you need to. It sometimes comes to a point where you can't tell by palpating the area where exactly you should put it,.. in these cases you really just need to guess,.. try to keep it uniform,.. But for acoustics you generally want coverage around and even behind the speaker itself.. For rattles you want to fill in gaps where the door is vibrating. Two different things,.. both should be addressed. Also, you can use other materials, it doesn't have to be just material meant specifically for sound deadening in vehicles.. Foam, Closed Cell foam, etc can be used (remember the door panel will cover up anything that looks unsightly) //content.invisioncic.com/y282845/emoticons/smile.gif.1ebc41e1811405b213edfc4622c41e27.gif

I'm sure more will chime in with more advice.

 

[calebkhill 10+ year member]

Just spread evenly.

I'm thinking the outer skin would serve a better purpose, as the inner skin is usually molded and rigid anyway......?

 

[keep_hope_alive Premium Member]

Just spread evenly.I'm thinking the outer skin would serve a better purpose, as the inner skin is usually molded and rigid anyway......?

when supply is limited, application should be based on analysis and experimentation. knocking and listening is the easiest method.

both inner and outer skins can be resonant. i explore all options.