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2004 Eclipse Spyder GS
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10 Posts
Discussion Starter · #1 ·
Everyone told me to replace the stock Infinity sound system in my '04 Spyder with a modern head unit, but I like the stock system. It just needed a bit more bass! So I embarked on the subwoofer install journey. And like the jankster I am, I wanted it to be as low-cost as I could get it. Unfortunately, I didn't think to take pics until the very end, so "wall of text" it is, but I'll start with a pic of the final product for the TL;DR crowd.

Car Automotive parking light Vehicle Automotive tail & brake light Vehicle registration plate


I wanted the whole thing to fit snugly into the trunk of the Spyder, so I started with a JVC 10" and a small amp from Boss Audio. After ordering Amazon's recommended Line Out Converter and install kit, I was ready to start the project.

First, the wiring. Following instructions from another post, I drilled into the rubber grommet behind the driver's side wheel-well cover for the battery power cable. It took a few tries to realize the grommet is double-walled! Once I got the drill through both layers, I ran a coat-hanger fish tape from the cabin out to the wheel-well and used the time-honored electrical-tape-and-pull method to get the wire through the holes. Inside the cabin, I ran it down the driver's side electrical channel under the footboard trim and behind the rear seat trim panel into the trunk. Yeah, it involves pulling a whole lot of bits and pieces off the car, but worth it for an invisible install.

For the remote start, I tapped into the accessory power outlet inside the center console. With the passenger seat removed (I'd pulled it out just to have a look at the stock Infinity amp), it was easy to run from the console to the openings in the carpet for the stock amp, and over to the passenger side electrical channel. From there or was the same run to the trunk.

Since I already had both rear cabin trim panels pulled to run the power and start wires, it was easy to tap into both rear speakers to get both channels for the sub inputs, then run alongside the other wires into the trunk. That's it for the cabin!

Inside the trunk, I started by running the positive speaker outputs through a pair of passive inline low-pass crossovers, because my cheapy amp didn't have a built-in crossover. The amp did have high-level speaker inputs which I tried at first, but the output was weak, so I went from my speaker taps to the LOC and then RCA's into the sub.

I decided to install the sub on the driver's side, so I opened up the trim on that side and was happy to see how much space there actually is in there! After testing the conductivity, I connected the ground wire to the antenna bracket screw. Then I cut a plywood panel to fit across the gap in the body, screwed the amp, crossovers, and LOC to it, then bolted the panel to the body through a couple of the random holes near the antenna bracket.

With the trunk trim back in place, the only evidence of the install was the speaker wire for the sub poking out of the trim. And at that point, I realized I'd completely forgotten about the speaker box!

After some hunting online for about on hour for a box that wouldn't basically take up the entire trunk and discovering that nothing short of blowing my budget entirely would do the job, I pulled out my measuring tape and middle-school birdhouse-building skills and got to work.

The resulting geometry fits perfectly between the trunk trim and the spare tire cover, with a decent resonating chamber and front-ported labyrinth. I did think to snap a picture of it before I installed the sub in it:

Wood Automotive tire Art Font Artifact


I'd picked up some Duck heavy-duty foam weather-stripping (so much cheaper than the stuff from the auto store!) for gap-filling on my convertible top gutters, so I used that for isolation on the sub. I ran a ring of it around the hole and screwed the sub down into it. All connected this thing has a nice, solid bump that rattles the trunk lid. With some more weathering-stripping to stop the rattle, I called the install done for now. Maybe next month I'll wrap the box to finish the look lol!

Automotive tire Automotive lighting Motor vehicle Automotive design Camera lens
 

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2004 Eclipse Spyder GS
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10 Posts
Discussion Starter · #4 ·
It seemed like nobody in the audio communities could agree on any one material. Some folks swore by MDF, some insisted on fancy hardwood plywood, some even claimed flexible fiberboard was the best. I watched some videos where people tested different materials and they only saw a difference up on the high frequencies. So I went with what I had lying around and just made sure the box was solid 🤷‍♀️
 

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2004 Eclipse Spyder GS
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Discussion Starter · #7 · (Edited)
@Sisyphus58 I had the sub, construction materials, and low-pass crossovers lying around from previous projects, so the only things I bought were:

Boss Audio R1002 amp $40
Leige Audio 8 gauge subwoofer installation kit $20
PAC variable line out converter $10
Package of assorted electrical connectors $10

TBH, if I'd been more certain the whole project wasn't going to be an epic fail, I'd have shelled out more for a higher powered amp. The sub is 400W max at 4ohms, and the amp (200W max at 2 ohms) can barely push it to 50W.
 

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2004 Eclipse Spyder GS
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Discussion Starter · #8 ·
@Widgmaster your point is solid. MDF has great rigidity and it ages well, while OSB is more flexible and swells and weakens with humidity. But since I live in a desert, our maximum humidity is like 30% and the big issue with everything is sun damage
 
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