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randywebb Samba Member
Joined: February 15, 2005 Posts: 3815 Location: Greater Metropolitan Nimrod, Orygun
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Posted: Fri Oct 18, 2013 1:04 pm Post subject: Sound Treatments for Vanagon Doors |
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some ideas; do's and don't for the doors
I did this (but would do it differently next time):
(that arrow points to some torn up spacer material; I cut a piece out of an old wet suit to substitute and it is shown in the VB2 pic below)
It took a while to make the wood spacer or adapter and I think mounting separates would be a better idea. The bass speaker can go lower in the door, and the tweeter _could_ go here, but the very best place would be to fab a small enclosure for the tweeter that fits into the corner of the windshield at the base of the A pillar and dash (there is a an aftermarket product opportunity for someone too).
I do believe in using high quality speakers and not doing things twice - those are Focals.
Go ahead and stick any leftover scraps on the panels (see mine below the speakers).
I used plywood for a mount to be sure it lasted as long as I own the van. My thought was that the superior dampening of a mdf mount might be overcome by the inferior stability of mdf in wet environments.
A thin layer of neoprene or similar (go to a skin diver shop) should be placed in between the speaker and the mount. Focal puts something there for you, so you don't need to do that.
A Word About Speaker Placement:
Your ears & brain are sensitive to where sound comes from, except for very low frequency sound (which has a long wavelength relative to the size of you hear, which is where your ears are located!). These long wavelengths are produced by 10" or 12" dia. speaker cones NOT by 8" speakers. 8" speaker are woofers, not subs...
8" dia. speakers are NOT sub-woofers and they belong in front of you, not behind you. I suggest putting them in your doors.
My bet is that the optimum setup would be 4" speakers in the stock locations, tweeters in the corners as per my comments above, and 8" speakers lower in the doors. Use digital crossover technology and drive every speaker with a separate amp (yeh, 6 of 'em). After all, it's already a money pit, right? _________________ 1986 2.1L Westy 2wd Auto Trans.
Last edited by randywebb on Fri Oct 18, 2013 1:56 pm; edited 2 times in total |
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randywebb Samba Member
Joined: February 15, 2005 Posts: 3815 Location: Greater Metropolitan Nimrod, Orygun
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Posted: Fri Oct 18, 2013 1:08 pm Post subject: |
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While the door is opened up, be sure to check for any rust; anything needing adjustment (window mechanism), any seals needing replacement, etc.
Consider installing power/remote locking (I had a stereo shop do mine with aftermarket items and I then cleaned up, primed & painted the holes they drilled).
My Van's doors seemed pretty clean at the bottom but be sure and check yours - vac it out, use a rag, borescope or mirror, etc. _________________ 1986 2.1L Westy 2wd Auto Trans. |
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randywebb Samba Member
Joined: February 15, 2005 Posts: 3815 Location: Greater Metropolitan Nimrod, Orygun
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Posted: Fri Oct 18, 2013 1:20 pm Post subject: |
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Next, clean the inside of the outer skin of door. USe hot water and a strong detergent (polar solvent) on rags; after that dries, use a non-polar solvent. This ensures you have removed all types of dirt and debris, grease, oil, etc.
Next, apply a sound deadener over at least 25% of each separate panel. You can use a spray if you are in a production environment, but most DIYers will want to use a stick-on sheet product, as I did.
I like Cascade Audio products because when I surveyed dozens of providers* Cascade was the only place that could back up their claims (with ASTM spec.s) or could intelligently discuss acoustics. By that, I mean engineers, not installers. The former means they have actually tested their products.
Another tip is to never buy old stock from the back of a stereo shop or eBay, as the adhesive ages over time and will not stick well.
Be sure to press the material on well, and rap on the panel with your knuckles as you go. When the noise changes and sounds 'dead" (muffled), you have enough material on that particular panel, and can move on to the next one.
If the door skin is welded or adhered to a structural member then you have multiple panels.
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* I say providers, rather than manufacturers, as I don't think every seller makes their own product. I'd bet large chemical companies are making these things to spec.s provided them. _________________ 1986 2.1L Westy 2wd Auto Trans. |
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randywebb Samba Member
Joined: February 15, 2005 Posts: 3815 Location: Greater Metropolitan Nimrod, Orygun
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Posted: Fri Oct 18, 2013 1:23 pm Post subject: |
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The 2nd layer (moving inward from the door skin) would be a layer of closed cell foam, and then a layer of heavy vinyl. These are often sold as a single combined product called MLV (mass loaded vinyl).
The idea is that sound waves will be trapped when they hit the vinyl (some portion of the sound energy will make the vinyl resonate, but the resonant frequency will be quite low).
For the doors, I skipped this step because.... well, because it's a Volkswagen...
ok, here is the art shot so far:
_________________ 1986 2.1L Westy 2wd Auto Trans. |
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randywebb Samba Member
Joined: February 15, 2005 Posts: 3815 Location: Greater Metropolitan Nimrod, Orygun
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randywebb Samba Member
Joined: February 15, 2005 Posts: 3815 Location: Greater Metropolitan Nimrod, Orygun
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Posted: Fri Oct 18, 2013 1:51 pm Post subject: |
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VW used a thin waterproof plastic sheet under the interior vinyl door card to seal the door enclosure and keep water in it, not in the interior.
You also want to seal the door enclosure for sound, not just for water so throw away that plastic sheet.
Use this stuff instead:
http://www.cascadeaudio.com/car_noise_control/VB2_Vinyl_Damping_Material_Installation.html
You use a heat blower gun and mold the VB2 to seal the door enclosure.
Mine looked like this:
Note the small vinyl tubing to let the actuator rod for the door handle operate. You can seal electrical wire runs with a thinner material, even duct tape.
Now, the important thing, is to NOT do what is shown in the photo -- at least, if you use the thicker than stock Sewfine door panels (which I don't like after having bought them anyway...).
See where the VB2 comes right up to, and over, the holes for the plastic retaining snaps? Don't do that. The panel will not stay in place as the snaps will not hold it.
Instead, take more time and cut the VB2 so it just barely comes past the door openings and onto the inner skin, leaving as wide a margin as possible around the snap holes.
I hope this helps others. _________________ 1986 2.1L Westy 2wd Auto Trans. |
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randywebb Samba Member
Joined: February 15, 2005 Posts: 3815 Location: Greater Metropolitan Nimrod, Orygun
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greebly Samba Member
Joined: August 27, 2009 Posts: 966 Location: Here and now
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Posted: Fri Oct 18, 2013 4:04 pm Post subject: Re: Sound Treatments for Vanagon Doors |
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randywebb wrote: |
These long wavelengths are produced by 10" or 12" dia. speaker cones NOT by 8" speakers. 8" speaker are woofers, not subs...
8" dia. speakers are NOT sub-woofers and they belong in front of you, not behind you. I suggest putting them in your doors.
My bet is that the optimum setup would be 4" speakers in the stock locations, tweeters in the corners as per my comments above, and 8" speakers lower in the doors. Use digital crossover technology and drive every speaker with a separate amp (yeh, 6 of 'em). After all, it's already a money pit, right? |
4" speakers can be made to operate in the subwoofer band of frequencies using an enclosure and proper porting. The size of the speaker determines how well it can roll off the frequencies it is intended to operate at. Basically how effecient it operates at for the range it is utilized for. 8" woofers are actually more efficient and tend to produce more controlled bass response and less distortion than larger speakers , all things being equal except size. One of the most efficient and better sounding subwoofers I am aware of is a Helmholtz resonator using dual 6" or 8" speakers in a properly tuned (ported) chamber.
I like the door sealing and the matt you placed behind the speaker and imagine it sounds quite good. |
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