Wanted to get the forums thoughts on putting a sub in the spare tire well. I've determined that I will have enough volume in the box, even making it out of MDF, for a 12" Infinity Perfect I already have and either the spare tire or the amp, cap, etc. I only use the car on evenings and weekends and rarely go to remote areas. I have AAA Plus so I have 100 miles of towing included. I'm leaning toward putting the whole stereo system in the well and just throwing in the spare when I take a trip somewhere. What would you do?

 

Sounds like you know what you are doing, which is most important for any after market alterations. We had a poster some time ago who was installing something of a mega power stereo and was reporting serious electrical fail issues. We pointed out that he was pulling currents through stock wiring harnesses that were not designed to carry anywhere close to that much currents thus, the damage in the wiring or the computers could be permanent. Just remember the formula;

Current = Watts/Volts, thus a 1300W stereo at 13V "in theory" could pull 100 Amps.

Other than that factor, your project seems quite doable. Good luck. An other electrical advice: never assume that if you fuse a circuit it would be protected. A fuse could blow AFTER the weakest component in the chain already melted-off.

Albert

 

Anyone that installs a aftermarket sub in the trunk should run a fused power line directly from the battery, not the harness. The battery is in the trunk anyway so it shouldn't be a problem.

As far as using the spare tire well... I'd probably build a box into the left side rear of the trunk so the spare tire, battery, and rear seats can still be accessed like normal. Of course it would be pretty slick to have it in the spare tire well so it's up to you.

 

At this point I'll only be running one amp and will run a 4 gauge supply off the battery. It will be overbuilt as I already have left over supplies from the last few installs. So I won't have any electrical issues. Done this quite a few times

 

From a thread I posted in about 6 months ago...
Totally worth it!

 

What size woofer and how much power is your amp putting out? Do you ever put the spare in on trips?

 

On my xkr I left the tire but put pulled the jack out and used the space for the amp / processor rack. I had boxes built for the sides to each take a JL 8". I figured I can get AAA to put the spare on so I don't need the jack.

Given the size of the XF trunk, I'm going to put either a 12 or 10 premade box in the trunk. If I need extra trunk room I can pull the sub out. I'd prefer that to having to move the spare tire in and out.

I just picked up one of these used for $200 and I'm going to see if I can wedge it in.. HO110RG-W3v3 - Car Audio - Subwoofer Systems - H.O. Wedge

 

It's a 12" Treo Engineering RSX in a 1.5 cubic foot sealed box. It's getting about 500 watts rms via a Treo RSX 1600 monoblock. I used a simple PAC LOC with remote turn-on to wake the amp up when getting fed the oem speaker-level subwoofer signal.

I never put the spare back. I have AAA and I rarely go more than 50 miles from home.

 

I was just wondering if you are going to be replacing a subwoofer that is already in the trunk well? Didn't the '10 XFR already have a B&W subwoofer that was custom molded to fit beneath the spare? I would suspect that what you are proposing to do would be more and better bass than the stock sub, but if there is one there, I may be interested in acquiring that one from you and installing it in my XF.

 

Yes it does, but I need more bass than it provides. I'm not going to be selling the stock one though. Need to keep it for future resale. Sorry.

I think I've decided to put the sub and spare in the well and then mount the amp on the 60 side of rear seat. I think that will give me best of both worlds without making me compromise too much either way. When I get around to it, I will be putting up photos and diagrams of what I do that you could copy fairly easily. My enclosure will be a net of approx. 1.0 to 1.2 cubic feet (haven't done the actual math yet), but if you went with a shallow mount sub that could work in less than 1.0 it would be very easy to fit and a pretty simple box to make.

Concentrating on getting the tune/pulley done now. Hopefully will have time over the Thanksgiving weekend to get this done.

 

I finally finished my install. I would change a few minor things, but overall very happy. Have an Infinity Perfect 12 with dual 4 ohm voice coils run off an Orion 9200 making 225w per channel. Used and Audio Control LC7 for converting the signal, but only because my amp can't accept speaker level inputs. It's more processor than I need though since I'm not going to change anything else out. But bought it before the car.

Found out the "sub" adjustment is really is a level adjustment and not an EQ setting. Made the amp level adjustment for my Audio Control LC7 redundant, so I get to return it. Here is a pic. I'll post box dimensions if anyone is intetested.

 

2010 Kyanite XFR,
I am a bit of a novice when it comes to car audio. Any extra bit of information you can add would be a great help.

Thanks

 

The box I made is 24x14x8 outside dimensions. Using 3/4" MDF, you'll end up with about 1.0 to 1.1 cubic feet of internal space. That is enough for some 12" woofers and almost too big for many 10" woofers. The biggest limiting factor is the mounting depth of 6.5". You could make it taller and less deep, but know that the whole box, including any grill, would need to be under 10" (the depth of the well).

I made a shelf for the amp that's 14"x11" that I attached with brackets and cut the back corners off with a jig saw to make fit. In my install, I mounted a 1 farad capacitor under the shelf, but it isn't necessary unless you are using a very high power amp (over 500w) that isn't Class D (Class D are digital and much more efficient - almost all new mono amps are digital). Make sure to get an amp that has speaker level inputs and can turn on with the signal from the speaker wires, so that you don't need any outboard signal processor like I have. If you want something that works very well for this and has the Accubass technology to help with the bass response rolloff, there is a two channel version of my processor called the LC2. It would be perfect for this application, but takes a little more wiring to get done. Here is a link to the product AudioControl LC2i 2-channel line output converter for adding amps to your factory system at Crutchfield.com

To wire the amp, just use 8 gauge power and ground if you're under or around 500w of power, which would be plenty for either a 10 or 12. Make sure to have a fuse that equals the total draw of the amp plus a little more (probably in the 60 to 80 amp range) within 18" of the battery. SEE FOURTH PHOTO BELOW Leave the fuse out until you have it all wired. Take off the negative terminal. I didn't even take off the positive cable. If you look at the positive battery terminal, there is a screw that has another wire attached with a nut. Just put the power wire under that nut with the other wire and run it out the top side (about the 1:00 position from the back of the car). SEE FIRST PHOTO BELOW That allows the white cover to go back on. Take off the white clip on connector and unscrew the nut that the ground is attached to the wall of the tire well. It's actually a screw on both sides of the nut so don't worry if it comes out. I put the battery ground on first then the stereo ground. SEE THIRD PHOTO BELOW

I cut off the factory connector for the stock subwoofer and replaced it with bullet quick connects. SEE SECOND PHOTO BELOW Each pair in the factory wiring is twisted together and the orientation is (+) purple/grn (-) green/wht; (+) wht/brn (-) pur/org. Since you're going to be running a mono signal, it doesn't matter which will be right or left. Take some 16ga speaker wire and put the opposite part of the bullet connector than on the factory wiring and connect them accordingly. Make sure it's long enough to reach your amp.

Connect all the speaker inputs, the power and ground to the amp. On your amp, set your crossover to about 80-100Hz and your gain to about half way. Put the fuse in and see how it sounds. As I said before, you can use the "Sub" controller on the B&W system to dial in the amount of bass you want. If you're in the center of the range with music that has a normal amount of bass, that's a good place to start. That way if you have music that has a lot of bass (say rap) you can turn it down a bit to where it's balanced with the rest of the system. Same for music with weak bass, you just go up instead of down. If the bass is too strong at the half way setting on the B&W, turn the gain on the amp down a bit until it gets balanced. Also, if the bass sounds like it's too punchy in the top end, turn the crossover down a little at a time until it blends in correctly. You may have to redo the gain setting after getting the crossover frequency right. Just keep a small screwdriver in the car for a little while and keep playing with it until it sounds good with all music you listen to.

I also put weatherstripping along the plastic trunk tread plate where the cover makes contact with it to keep it quiet with the added bass. Works very well.

 

Good write-up, Kyanite.

If there's interest, I can create a "package" for these setups. I can build a box, select an amplifier well suited to our needs, pre-wire it (power and speaker interface), and ship it off. Being an authorized dealer of multiple car audio brands, I can create flexible packages based on budget and musical tastes.
For example, my setup went this way... this is what I would have charged a client for my XF setup:
custom subwoofer box with trim piece: $250
TREO Engineering RSX subwoofer: $200
TREO Engineering RSX1600 amplifier: $300
PAC Audio SNI-35 speaker adapter with remote turn on: $25
8 gauge wire (power, ground, fuse) and misc.: $50
Total parts: $800

For our forum guys, I can obviously do better than that, and there's no need to do something extreme like TREO Engineering. Thinking...
Box with trim piece: $150
12" Orion or PPI subwoofer or equivalent: $100
300-400 watt RMS mono amplifier with speaker inputs: $150
Fused 8-ga. pre-run of wiring to our batteries: $25
Shipping: $50

Total $475

I think anyone can install this themselves with a little coaching. Thoughts?

 

I would be interested

 

If all they had to do was cut off the factory plug, put on some bullet connectors, hook up power and ground and put in the inline fuse...I can't imagine anyone couldn't get that done with a few pics and purchase of a good crimper/stripper. I just wonder how much shipping would be for all of that? Seems like it would get expensive. I know you estimated $50, but would be curious if that is accurate because of the size of the trim piece and the box. Maybe offer a grill instead of the trim piece?

I'm going to edit my previous post to include photos of some of the items described that should help a bit more.

 

I would be interested as well.

Although I have the newer Meridian 325w system with auto-start. Not sure how much difference it will make. Less amp power I would suspect. Also the Auto-Start has a small lawn-mower type battery next to the main battery. So not quite as much room as you guys have.

 

A couple of things...
1. I'd prefer not to cut the factory subwoofer connector for those of us with the B&W system. In fact, I created a harness with female bullet connectors to mate to the OEM plug. I'd go this route for those of us with the factory sub.

2. Options/trim pieces are up to each individual. Shipping will vary based on total weight and where it's going (I'm in zip code 11004). Yes, a simple grill is an easier idea; I just offered the look that I had since it's very clean and looks 99% factory. Shipping will be more for that.

3. For those with the Meridian system, I can still work the same type of setup. I'd need to look deeper, but I assume there is a subwoofer in there as well. I'd have to build the box to fit your available space, but we'd still end up with a good solid box for a 12" subwoofer. Just to note, the total output power of our factory stereos has no bearing on the setup we have all been enjoying. It's just a matter of how to integrate the subwoofer signal (or full range signal for those without subs) to the aftermarket amplifier. There's a viable solution for everyone.

I'm open to suggestions. Happy to help those out who have the interest and the passion; I have been doing this for 20 years.

Cheers!

 

Yes the Meridian systems have a sub-woofer as well. It is mounted in a hollow plastic case that doubles as the spare tire shelf/holder. There is a quick disconnect for the sub near the battery and rear of the car. The sub speaker "fires" down. I believe it is the same mount as the B&W but not 100% sure.

The lawn mower battery sits forward of the main battery.

 

Looks great!