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Napoleon of DIYMA
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Discussion Starter #1
I have a problem with my doors resonating at around 150Hz, the doors are fully deadened (2 layers of Bquiet extreme).

From what I understand, I need to add mass to the door to stop this problem. So i basically looking for ideas and I'm also wondering if a better deadener will help (hushmat come to mind).

Vehicle is a SQ 2002 Dodge Caravan :surprised:

Thanks
 

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Mass loaded vinyl AND Foam decoupler.
This will stop external noise from entering inside.

see link for frequencies blocked. http://www.sounddeadenershowdown.com/products/mlv

I'm in the middle of installing this stuff in my ride and I've already lowered my radio average listening level from 19 down to 13 so far...

Dynamat/hushmat etc... stops panel resonating.
MLV will block road noise
CCF helps the mlv work properly (mlv needs an air space to be effective)

Any other q's just ask

Glen
 

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Napoleon of DIYMA
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Discussion Starter #3
yup but it's not the outside noise the problem it's the door panel resonating when playing music(car off). I think the BQuiet extreme is the culprit since it's the deadener that should stop this. The extreme work good to "seal" the doors but not so much to stop the vibration...

It's gonna be a pita to remove so i just want to confirm with you guys before ditching more $ and time into this problem.
 

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When installing the MLV and CCF the ccf will be on the panel side...so this should help with panel resonation.

If you remove the plastic panel does the noise go away?
Can you shove some ccf or rags inside the panel to see if it stops,

if so then ccf should work pretty good.

I would also suggest MLV.

glen
 

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Napoleon of DIYMA
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Discussion Starter #5
i did my testing without the plastic panel... also does decoupling the driver/baffle from the metal panel could help or it's really just the enclosure(door) that resonate because of the sound?
 

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Decoupling the driver should help, have you tried clay with bb's around the baffle?

could it be part of the window mechanism thats vibrating?

what about welding / bolting a strip of metal across the metal frame to help stiffin it up?

With the panel removed try pressing on the frame to see where it's vibrating the most and then try working on that area first.

just some ideas.
 

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I'm going out on a limb and asking, what is the door touching? What I mean by this is that you have 2 layers on dampening materiel on the door, that should keep it from resonating, but that part of the door also comes in contact with a plastic door panel, wires, rods, and the A and B pillars. In my experience, after you deaden the door, you need to pay special attention to prevent the vibrations from getting to the door panel. The plastic makes a ton of noise.
 

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Napoleon of DIYMA
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Discussion Starter #9
My testing was done without the plastic panel and the door was open. It's not rattle i get but really a huge boost in the 150Hz freq area and when i touch the deadener i can fell the resonance (vibration).

So far i'm thinking reinforcing the panel with rods and redeadening the doors with the good stuff.
 

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My testing was done without the plastic panel and the door was open. It's not rattle i get but really a huge boost in the 150Hz freq area and when i touch the deadener i can fell the resonance (vibration).

So far i'm thinking reinforcing the panel with rods and redeadening the doors with the good stuff.
Have you felt the outer skin when you hear the boost? Could be inner, outer or both but it sounds like you are on the right track. After all of the years spent arguing about whether asphalt based products were durable enough to use in a car, it's turned out to be a moot point - they are terribly ineffective vibration dampers.
 

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Napoleon of DIYMA
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Discussion Starter #11
well the inside (dampened) and outside vibrate almost at the same intensity. so it prove the point that the extreme is crap at stopping vibration.
 

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You didn't say what frequency range you are playing in your door... but adding more mass will just lower the resonant frequency. If you can add enough to get the door resonance to down below whatever the driver in the door is playing, that would be great.

If you want to move the resonant frequency UP, you need to brace, and stiffen the door.
 

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Napoleon of DIYMA
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Discussion Starter #14
That's the prob, they play from 40 up to 200Hz so i really need to brace. But if set the HPF to 125Hz (LPF200) i can clearly hear that the door resonate.

One thing i didn't mention, this minivan is competing in IASCA "rookie", that's the reason the midbass play so low, for daily it's set at 80Hz-200Hz.

here's an idea, i have about 1 inch depth in the door panel to work with so i was thinking building a large 3/4 MDF baffle that cover most of the door.I could attach it using well nuts and maybe use expanding foam between the 2...

The sludge and "duct seal" thing might also be an interesting.

Thanks guys, I appreciate all the comments/ideas, keep them coming.
 

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My Accord had a bad resonance issue in the 250-430 Hz range. It was cause by the door trim panel which had all kinds of open spaces in it. I went to Hobby Lobby and bought some 1" thick foam and filled every nook and cranny of the trim panel I could so that the only place for the sound to go was out of the speaker grill. I also put foam around the speaker itself because the door panel's speaker grill was 3-4" in front of the speaker so frequencies were bouncing around in there.

Its a pretty cheap solution. That foam cost less than $20.
 

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get some test tones,

Realm of Excursion

play them and see if you can create your resonance.

once it starts put pressure by hand on different locations and see if you can identify exactly where its coming from

then deal with it.

im guessing its vibration not resonance somewhere if the doors are well deadened inside and out and all over.
 

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Hey Basshead,

Any progress with the resonating problem?

Here is an interesting artical that deals with speaker cabinets.

SpeakerBuilding.com - Toccata Grande, Part 1, Page 9

Not exactly the same thing, but just the same there are some interesting points about resonation and materials.

Keep us posted on your progress.
 

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Napoleon of DIYMA
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Discussion Starter #18
Thanks interesting read.

The article confirm my big baffle idea, decoupling the driver seem to be a task that unless done perfectly will not help.

But my biggest prob of all is the lack of time to work on this project. Next comp is June 6th, so i need to find time to do this before the comp. When i open the doors ill take some pics of what i do.

shawglen where are you located?
 

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Napoleon of DIYMA
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Discussion Starter #19
im guessing its vibration not resonance somewhere if the doors are well deadened inside and out and all over.
The entire door is vibrating at ~150Hz, it's not like a rattle where you can pinpoint the source, the source seem to be the entire door.

The exterior panel didn't got deadener, but the vibration on the exterior panel and when i touch the deadener on the interior panel(metal behind the deadener) is about the same. This is telling that the deadener i used is not doing its job.

Next time I open the door ill try with a sine generator and pinpoint the exact frequency. Then try different things and test again with the generator to see if it stop or simply shift the resonant freq.

More to come
 

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Thanks interesting read.

The article confirm my big baffle idea, decoupling the driver seem to be a task that unless done perfectly will not help.

But my biggest prob of all is the lack of time to work on this project. Next comp is June 6th, so i need to find time to do this before the comp. When i open the doors ill take some pics of what i do.

shawglen where are you located?
Right next door in greenfield park

Finding time...tell me about it. I've been on my deaedening project since last mid April.

June 6th Yes I hope to go...as a spectater that is.
 
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