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Showing posts from June, 2006

Status Update

No posts in a few days, just applying more and more Damplifier. I've bought another 40 square feet which should be enough to properly finish the rear half of the car and do the front doors. In addition, upon numerous recommendations I found online, I purchased 2 gallons of Spectrum, Second Skin's liquid deadener. Apparently the secret technique to getting the best results is:
Average 2 layers of Damplifier Pro on the the whole car.Paint on a layer of liquid deadener (either Spectrum, or Spectrum Firewall).Add a layer of Overkill (a closed cell, neoprene foam).In that order. So, in addition, I got 60 square feet of the Overkill to finish of the rear half of the car. The liquid deadener is almost a must over top of the Damplifier matting. The sticky butyl stuff on the back has a tendency to squish out between the seams and make a real sticky mess of anything that comes in contact with it. The liquid Spectrum should provide a nice, clean surface for everything to be laid down on l…
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And More Subwoofer Box Design

Here's my subwoofer box design. As I mentioned previously, I've gone with a push-pull design to reduce the size of the box. I'm also using two slot ports. The whole thing will be built out of 3/4" MDF and then finished with carpeting.

The drawing doesn't include the contours to make it fit in the back seat wells. I'm going to have to cut that to fit. The volume there won't be exact, but after playing with the numbers and looking at the frequency response curves, I think it will be within my threshold of satisfaction.
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Damplifier Pro, Round 2

Still going... I'm not quite half-way through the 80 square feet I bought. I took some pictures and I'll put them up later. I learned a couple more things today.

You get what you pay for when you're buying ratchet sets. That $10 set at Advanced Auto sure looks nice though.The matting is pretty flexible, but bubbles are a real pain. Be sure to squeeze as much air out as possible by rolling it on and pressing it down as you peel back the paper.Other than that, I've learned it is a time consuming and laborious process. I sure hope it's worth it!
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Picture Album Started

So, there are too many pictures to post them all here in the blog. I'll start including relavent pictures in entries from now on. However, all the pictures taken will be available at http://picasaweb.google.com/damonkohler/cougarproject2006/.

Here's a quick photo timeline of the progress so far:

Before-shot with the sub box in the back.


Shots of removing the interior.




After-shot of stripped interior.


Measuring the volume of the seat wells to do my subwoofer box calculations.

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Damplifier Pro, Round 1

I've gone through two sheets of Damplifier Pro so far, and this is what I've learned:
2" strips work great for hard spots. Don't bother with more complicated shapes.The roller takes a beating. I'm really glad I paid extra for the heavy-duty rubber one.The sticky stuff is messy. Wear old clothes. (Doh!)Two sheets has gotten me through a single layer on one back seat well and 75% of one of wheel well. I have 38 more sheets to go. The plan is to first cover the rear half of the car. That is, everything from the edge of the back seat to the trunk but not including the roof. I'll be putting at least two layers in the place where my subwoofer box will go, on the wheel wells, and on the inner-skin where my rear speakers are. I'm trying to come up with something to fill the huge void between the inner- and outer-skin in the back. I'm considering corrugated mattress padding. It's worked in the past...
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Gear Arrived!

Everything arrived today and I'm getting ready to start installing. The first step is going to be cleaning and preping the surface for the Damplifier Pro installation. I've been doing some research on this and on what the problem areas are. Here's the site that made me decide to go with Second Skin's Damplifier Pro:

http://www.sounddeadenershowdown.com/

It has some great information and experimentation plus photos to back it up.

I picked up a heavy-duty rubber roller from Crutchfield when I ordered my stuff from them. That should come in handy while applying the Damplifier Pro. Even though their product doesn't hold up as well as Second Skin's, Elemental Designs has some nice information on where to apply deadening material.

http://www.edesignaudio.com/product.php?cid=10&pid=25&tab=Apps&cur=USD

I'm in contact with Anthony, the owner of Second Skin, and I'm waiting for his recommendations on surface preping and application areas. It's very war…
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More Subwoofer Box Design

I've decided to set up a push-pull or isobaric box in order to reduce the size requirements. Doing so actually reduced the size by almost too much! And, in addition, I've had to go to a 2-chamber bandpass arangment since I don't know how a partially isobaric configuration would work (i.e. where only the vented chamber is isobaric) and I don't like the other options for 3-chamber isobaric (typical requires 4 drivers).
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Subwoofer Box Design

Designing the box has been a very difficult problem. The math isn't complicated, and is easily done with a spread sheet, but unfortunately I can't seem to make the box as small as I'd like to. This, of course, is because I'm building a bandpass box. But, I'm more willing to compromise on the size of the box than I am to compromise on the type. Building a bandpass box means that I can keep my speakers enclosed and protected. I hope to make the box look inconspicuous and easy to pack stuff on top of. Having two exposed 10" woofers doesn't accomplish either of those goals very well.

So, I'll be using a 3-chamber bandpass with 2 sealed sections and 1 vented section. I'll have 4 slot ports on my vented section. Here are my calculations:

Box Calculations for Fl
Vas 101.14 l
Fs 30.5 Hz
Qts 0.445
S 0.7
b 0.7206
Fl 42 Hz
Fl' 0.6127868852459
Fh 91.3894382022472 Hz
Qbp 0.90392587983616
Fb 61.95447041573…
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Cougar Project 2006

Project Overview
Second Skin, Damplifier ProAlpine CD headunit
4 x Kenwood 50W 6" x 8" component speakers (dome tweeters) with foam baffles
Alpine 4-channel x 40W amplifier2 x 10" Pioneer 350W subwoofersRockford Fosgate 2-channel x 90W amplifier
Custom subwoofer boxThe goal of this project is to improve my car stereo while allowing for future upgrades and increasing the cargo room in my car. To do this, I've removed the back seat and the large bandpass subwoofer box I had previously installed. In their place, I'll be building a custom bandpass box into the back seat well that will, hopefully, be almost flush with the trunk (within a few inches anyway).

Future Upgrades
I want to eventually complete some upgrades to the new system, so I'm building it with these goals in mind:
Battery relocation2 x Alpine 220W mono-amplifiers to power the subwoofersTouch-screen GPS headunitStatus
I have so far gutted the rear interior of the car. Next I'll be preparing the surfaces…
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