mtndew1

Just bought a 2018 XLT with Sync 3 non-BO/Sony and the sound system could use some help. The bass is "ok" but I want to start with enhancing this since it's relatively easy (or so I think). Let me also say I'm not a professional at anything including what I do for a living, I've made a career out of knowing a little about and or being willing to try a little of everything. I'm not scared to be wrong, I welcome tips and guidance on how to do things better, I almost always do things twice because I failed at it the first time but my point is if I can do it, so can you.

My Goal: To build a custom woofer box that fits a down firing thin 10" woofer under the 40% side of the back seat that matches the profile of the seat and allows full floor access to the 60% side if I fold up the seat. I want to do it for a less than the of the cost (not counting tools) of the factory kicker add on woofer, it needs to destroy it in quality and quantity of bass and hookup up to the rear c- pillar factory plug for source. I don't like spicing wires or messing with factory electrical.

First let me start off by thanking, @slodat, he built a rather impressive box for the back of his truck that gave me the ideas for mine. I clearly don't have his ability of shop full of tools for woodworking but I though I would give this a shot anyway. Feel free to chime in and steer me the right direction anytime......please.

Here is a picture of @slodat' box that inspired me:





My Secondary Goal: To add a 6 channel amp/dsp, replace the front components and rear speakers with better units, equalize and time delay them properly as well as control the woofer via the DSP using a RCA output to the dedicated sub amp. More on this later.

mtndew1

Step 1: How the heck did @slodat do those sides on his box? I asked and did not get a response so I went it on my own surfing the internet (ok, I might be an expert at this). I came to the conclusion. there are 2 ways to accomplish corners like this:

Option 1: CNC routing which i did explore the cost to purchase the equipment and CAD, the learning curve to program the template as well as convert it into the format for the CNC machine. Then I contacted local CNC shops for pricing as well as found a local tool club that has one I could join or pay a day rate and decide it was just too expensive.

Option 2: Router Table doing template routing. I saw this technique used by http://www.caraudiofabrication.com/ in one of his videos. You need to take the product recommendations for what they are, part of his income but so far I found much of his install advice to make sense and be decent. I'll leave it to the pro's to critique it further.

Enter my router table:



I picked up a Kreg bench top unit and paired it with a Bosh 1617EVS. I looked for used setups locally but did not find anything just right until about an hour after I bought this new, I guess that is how it goes. I chose these because both the table and the router seem to have popular support and are considered to be decent entry level "quality" products. I could have saved a few $ and picked up a setup from the big box home improvement stores and I'm sure it would have done just fine but I try to buy tools just beyond my ability or purpose in hopes they last me a little bit longer before I need to upgrade to the real deal type of setup.

mtndew1

Next: I picked up a few goodies to try to jam into the truck with the least amount of intrusion into usable space:



Yes I'm a JL fan boy, I have been since I was in my teens 20+ years ago and still today with some home audio gear I have from them. It was the natural place for me to start my search in addition I have a locally owned shop that hooks me up with great prices on the equipment.

With that out of the way I selected this JL woofer the - 10TW1 because of the air space it requires. It's bigger brother the TW3 has a more shallow mounting depth it requires more air space or box size according to JL's specifications. Since my requirements are to fit under the 40% side of the seat only I wanted to choose a woofer with a very small required air volume.

Sealed Volume (net int.) - not counting the space the woofer takes up.
10TW1 - 0.35 cu ft / 9.91 L
10TW3 - 0.50 cu ft / 14.16 L

Additionally I factored in the physical sizes of the speakers, mounting depth will be a critical factor as I don't want to raise the seat height to accommodate this.

Mounting Depth:
10TW1 - 4.36 in / 111 mm
10TW3 - 3.25 in / 83 mm


Initially I had thought the 10TW3 speaker was my first choice due to the extra 1" of mounting depth you have play with but then I realized that both speakers overall height were fairly close. What JL did on the TW1 series speaker is push the flange toward the surround so more of the speaker is in the box vs sticking out past the box. What this meant for me is that I could increase the volume of the box without changing the final distance from the floor to the cone of the speaker. This seemed beneficial given my estimates put me very close to the recommended air space required for the 10TW1 without a lot of margin to spare. The question remains, will it fit? I sure hope so or my other car will be getting an upgrade.

If you don't mind taking up more space horizontally to gain air space volume for the woofer the 10TW3 would easily be my first choice due to the shallower mounting depth.

mtndew1

I made a cardboard template of the curve of the rear seat on the side that is facing out. I figure I'll just mirror the inner side and won't worry about it being too precise since you can't really see it very well and it looked to be about the same curve or close enough.




Transferred and cut out of 1/4" MDF.



Realized I don't have 4 high powered woofers like Slodat so I ought to thin out the profile some.




Here is what I ended up with for my side template, I'll clean up the curves and edges a bit more but this should be pretty close. It's an inch thick on the skinny part and 1-3/4 thick where I'll miter out for the front and rear panels.

HushCarAudio

Template tape and flush trim bit are your friends. Please use caution since your fingers will be close to the bit. Use a protective tool if possible. You can make your own router shield for really cheap. It's totally worth the effort since you could possibly chew up your hands.

mtndew1

mtndew1

gintyfab

Great start and nice work with all the research. One tip/suggestion is look at the box you posted. the curved pieces. A nice easy way to make the transition from your curved piece to the side and front pieces, is to make a step down section. it almost looks like 1 stair tread.
This allows you to make a nice secure bond between the two pieces.

mtndew1

gintyfab

it's easier to do it from the template, rather than the jigsaw because you can get a more consistant surface, which equates to more surface area when gluing.