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View Full Version : Fourthmeal's next audio project now in 3D!


Fourthmeal
07-23-2008, 11:17 PM
I'm posting this in hopes that it might inspire some of you some way, some how. As with all systems I do, you're welcome to take any ideas and solutions as your own, and improve upon them to your hearts content.

This thread will document the build process of one of my family member's daily drivers. This is for a 2008 Ford Focus, but it could easily be reworked and slightly adjusted for those with other vehicles with the spare tire inside.

How I do it:

Take careful measurements of the trunk area. Draw on graph paper a scale version of what you are measuring, its ok to be messy, just get all the critical angles and measurements.

Transfer that graph drawing to regular paper, keep the scale in check, but make your drawing more simplistic and without measurements written in.

Photo scan your drawing, keep the scale 100% and save a copy to your computer. Now you can make as many copies as you want of your trunk, to draw out different solutions on top of the basic form. Try drawing different possible solutions, such as a false floor or a corner-loaded setup. Visualize what will work best for your needs, and make that your #1 option. Photo-scan that one into your computer, as a backup in case your original plans get lost.

With a program like Google Sketch, try to make your idea come to life, at least the outline of the design. This way you can see for yourself what your 2D drawings showed. Here's what you get:

http://fc03.deviantart.com/fs31/i/2008/202/9/5/trunk_CAD_drawings_1_by_Fourthmeal.jpg

http://fc08.deviantart.com/fs31/i/2008/202/3/3/trunk_CAD_drawings_2_by_Fourthmeal.jpg


That's a rough general feel for what I'm going for.

The main deal about this build is to work around a full-size spare in the trunk. The factory Focus doesn't even have a spare, BTW! It just has a sleezy can of fix-o-flat and an air compressor. That's not going to cut it when something goes wrong, so I'm integrating a fullsize spare into the trunk. That's why the CAD drawings show a little curve in them on the sub box. That's part of the spare tire well area. The other thing to notice is that rather then build a system that just rests close to the rear seatback area in the trunk, I configured this one so it sits relatively flat across the trunk, and borrows the entire width of it with the amp rack and part of the sub box. That portion is about 3.5" inches tall, which so happens to be the height that will allow the factory trunk pass-through of the seatback to the cabin, almost completely flush. Compared with the trunk, the seats fold down about 3 1/4" above the trunk's baseline. So, with the amps like this, items can still pass right through the trunk for maximum utility. The subs box sits higher of course because the subs aren't that thin, but by being as thin as reasonably possible, and up against the side of the trunk on just one side, very little usable trunk space is sacrificed. So, the car gets full spare tire (full size) utility, two subs, and full pass-through utility of the trunk. This is of course exactly what we're going for....perfect compromises!

The taller platform holds a pair of subs, stands about 6.5" tall. The rectangle in front of the subs is going to be a digital processor to integrate the factory dash radio to the aftermarket amps. The lower platform is the amp rack, holding two Alpine MRP amps, the MRP-M500 and MRP-F300. The center section will hold the required distribution fuse blocks and ground blocks.

This project will probably be slow-going, since the person I'm building it for is in the Navy, serving as an air traffic controller, and only can visit on the weekends and intermittently at that. Still, the way I see it, once I get the base platform figured out, I can build it without the car in my hands, and work on it on my own time while he handles his work.

The system plan:

The aforementioned Alpine MRP-M500, and F-300 amps, 50w x 4 for the woofers and tweeters of the front stage, and 500w x 1 running in parallel to some Blueprint 10" subs (same ones I had in my older setup...so perfect for my client...er brother in law.)
The Alpine PXE-H650 digital processor. This will perform active crossover, time correction, pre-amp level, and EQ duties.
Alpine Type X - REF components, with the crossovers thrown out and the Alpine digital processor used instead.
Factory crap rear speakers running off the factory crap deck. I don't do rear speakers.
A full 62sq. ft. roll of RAAMmat, and 4 yards of Ensolite foam.
Knukonceptz 4 gauge wiring, with a Streetwires CBR44 distribution block (one of the few that contains the power AND ground distribution in one single unit!)
Streetwires battery terminals


Thoughts?

Fourthmeal
07-25-2008, 11:51 AM
Oh, the sound of crickets! Its deadening! LOL. This stuff isn't your style for most of you, huh?

kansei
07-25-2008, 12:57 PM
I just haven't been around, otherwise I would have responded. Thanks for the bump --and no, it isn't my style, but I respect it and from what I've seen you do great work.

the way I see it, the only way to make a car a rolling audiophile's wet dream is to make it really heavy and isolated from the road, and I drive a mazda because it is light and connected to the road. They're definitely mutually exclusive haha. I can make my home theatre as heavy as a car and it doesn't negatively affect the house at all :)

but go on, I do really like that design and the fact that it minimally compromises the trunk passthrough. The P5s like mine without factory spare tire sub (like 4" sub) step up 2.5" or so to the seatbacks as well, it's very annoying when loading the trunk

Fourthmeal
07-25-2008, 02:49 PM
Ahh, too true my friend. There are always compromises. Allow me to suggest this though:

It doesn't have to weigh a lot anymore. Good equipment can be both light, and great sounding. Good sound deadening does way a little bit, but I'm not sure if you could actually detect it. The lightest deadening brand I know of, Cascade Audio, is not a mass-loaded material like most, but instead is a visco-elastic material that is feather-weight. Probably adds 5-10 lbs to the entire car, completely covered. That's less then 2 gallons of fuel.

A good amp weighs only a 2-3 lbs.

Front components maybe weigh a pound for both sides together.

A subwoofer can potentially weigh a TON, but there are some models out there that specialize in light weight, small size, and still pack a punch. Especially if you are willing to put in something that just blends in with the music as opposed to something that dominates it (can't stand that type of system anyway.) Let's say it would weigh no more then 3 lbs.

That means you'd be sitting around 11-18 lbs or so, complete, give or take, in equipment. A sub enclosure actually can be quite light with a good fiberglass box, so I'll say that will weigh 3-5 lbs, and an amp rack, maybe a pound itself.

So, for a complete system done and ready to go, you'd weigh in around 18 to 23 lbs tops. Or, as I like to figure, about 3-4 gallons of gas.


As for this system you see drawn up above, well the client (my bro-in-law) doesn't care much about weight, and likes to crank it up beyond what I would consider "conservative" quite often, so double subs and extra amp power was needed to meet his goals. Also, because fiberglass materials themselves add up to a higher cost of production, he opted for a 99% wood setup, although I'm going to utilize lighter birch plywood portions where I can so I don't end up building a back-breakingly heavy setup that costs him MPG.


Here's how you stay light:

http://www.woofersetc.com/images/products/6395.jpg 5ch Alpine PDX-5

http://www.woofersetc.com/images/products/3080.jpg Neodymium component set, slim-style.

http://www.woofersetc.com/images/products/6562.jpg Neodymium slim subwoofer, easily.

kansei
07-25-2008, 03:54 PM
I just use an infinity basslink and crappy MSP front door speakers (no rear door speakers at all) + stock tweeters. Basslink because it takes one screw to remove it from the bracket + loosening 3 others to unplug it from the car, and it's out almost every weekend during the summer for autocross.

front door speakers amped from a pioneer premier P880PRS

trust me for home stuff I'm an audio snob (headphone snob too) but I could care less in my car where engine noise, tire noise, and wind noise (always have the windows open, even when it's raining) dominate.

Thanks for the info though, it's good to know that you can make a decently lightweight audio setup.

Can't wait to see some real life photos of that box, looks like it'll integrate really nicely when done. Why not go with a donut-style spare to save even more space?

Fourthmeal
07-25-2008, 05:55 PM
Nice call on the Prs880. If that's the one I think it is, you are under-utilizing its ability to go full 3-way without an additional processor! ACTIVE front components are an amazing thing, and you're extremely close to already being able to do that (again, if that's the same head unit I'm thinking of.)

I'm not a snob about home audio, but considering I had many years of selling, designing, and installing home theater setups, I definitely have my opinions. My Missions will be with me until I die, and my Sennheiser earphones will be my golden standard for some time, I imagine. So, I'm definitely with you on this matter. Thing is, I'm like, NEVER at home, and I'm in a car all the time, so it just makes sense to optimize the audio environment of where I am the most, at least a little bit. Besides, distortion and frequency range issues gives me a migraine. Seriously.

Because the car doesn't come with any form of spare tire, it is just as cheap it seems to get a full-size thrown in. The depth of the tub built into a Focus actually holds a full-size (since it is a Euro vehicle too), and it makes sense that someone who drives as much as my bro-in-law across the desert between Cali and Vegas probably should have the extra insurance of a full-size.

BTW, a set of quick-disconnect molex connectors would be easy to make for a quick-release amp/sub setup. Or, just mount the super-tiny amp somewhere under one of the seats, and never worry about it. Then, a simple in-out box setup using factory bolt points should be similar to what you are accustomed to with the basslink.


All these things I know are off your radar of things important, but I put them out there so you'll know it is easily possible to make things better, AND still not have to be mad about adding any appreciable weight.


I just use an infinity basslink and crappy MSP front door speakers (no rear door speakers at all) + stock tweeters. Basslink because it takes one screw to remove it from the bracket + loosening 3 others to unplug it from the car, and it's out almost every weekend during the summer for autocross.

front door speakers amped from a pioneer premier P880PRS

trust me for home stuff I'm an audio snob (headphone snob too) but I could care less in my car where engine noise, tire noise, and wind noise (always have the windows open, even when it's raining) dominate.

Thanks for the info though, it's good to know that you can make a decently lightweight audio setup.

Can't wait to see some real life photos of that box, looks like it'll integrate really nicely when done. Why not go with a donut-style spare to save even more space?