The time came to install an aftermarket amplifier and subwoofer in my M to compliment the factory sound system. Here are the instructions to do this as I remember them.

As has been noted before in other threads leaving the rear ANC (Active Noise Control) microphone hooked up negatively affects the sound output of the new subwoofer. I chose to cut ONE of the two rear microphone wires at the Bose amplifier to resolve this issue. Before I cut this wire while the vehicle was at a standstill, the new subwoofer would hum very loud. It would not stop until the car started to move or I turned the gain all the way down using the remote gain knob.

What you need:
Amplifier wiring kit
- Power Cable
- Ground Cable
- Fuse (or circuit breaker)
Subwoofer
Subwoofer enclosure
Amplifier
Line Output Converter aka LOC (if you amp does not have one built in)
Wires, terminals, T-taps or Inline splicers
Electrical tape
Wire tires
Hand tools - Blade, screwdrivers, etc.

Optional needed:
Soldering iron
Heat shrink tubing

Wiring Diagram:


*** IMPORTANT: *** Every automotive repair and modification manual, experienced auto mechanic, and car enthusiast will tell you to disconnect the negative battery terminal before starting any work on your vehicle. It is a safety precaution that will help keep you from getting shocked and, possibly more importantly, will keep you from damaging your vehicle's electrical system. The negative is the electrical systems ground and is represented by "-" or minus symbol and is usually black in color (red is positive). Disconnect the negative battery terminal before starting any electrical work on your vehicle.



Disclaimer: Use any and all of this information and instructions at your own risk. If you are not comfortable have this work performed by a trusted professional (not Best Buy).

Installation Steps:
These steps are organized to be the most logical when reading them. Some of these may overlap when actually being performed. Let's get started.



Under the Hood
a. Remove the battery cover using the pop clips
b. Remove the battery surround using the pop clips
c. Remove the right side / passenger cowl cover using the pop clips and the manual release clip at the center of the windshield
d. Create a hole in the rubber grommet for the power wire to pass through into the cabin
e. Pass the power cable through the hole into the cabin; I taped the power wire to a long screwdriver and pass it through carefully. From the cabin I removed the tape, backed the screwdriver out, leaving the power wire in place.
f. Once all other steps and have been completed connect the power wire to the battery 12V (+) using an appropriate fuse
g. Seal the power cable at the rubber grommet with some silicone
h. Reinstall the cowl cover, battery surround, and battery cover

Power wire (blue) and unrelated DRL remote wire (red)


Power wire and Remote wire covered


In the Cabin
a. Remove the glove box
b. Remove the passenger kick panel
c. Remove the front passenger side door jamb cover
d. Remove the rear passenger side door jamb cover
e. Remove the lower rear seat cushion; there are two clips at the front of it that release it – VERY easy.
f. Remove the four nuts at the bottom of the rear seat back that secure it
g. Lift the rear seat back up and off the hooks at the top of it and lean it forward onto the backs of the front seats, there is no need to fully remove it from the vehicle
h. Pull the power cable from behind the glove box into the cabin leaving a little bit more than is needed to connect it to a fuse and the battery under the hood
i. Route the power cable down into the white door jamb clips along the front passenger door to the b-pillar.
j. Route the power cable through the b-pillar to the rear door jam
k. Route the power cable through the door jamb clips along the rear passenger door to what I call the BRIDGE wire housing (due to its shape)
l. Route the cable trough the white plastic BRIDGE wire housing; I opened this housing up using the clips along its sides (took some trial and error) and inserted the power cable. It may be possible to push or pull the power wire through the BRIDGE wire housing but I was not able to. Pushing did not work and pulling after fist feeding a smaller gauge wire through felt like It might take more force then I was willing to use.
m. Run the power cable up the rear wheel well to the large white plastic plug
n. Make a hole in this white plastic plug and pass the power wire into the trunk compartment; I covered the power wire with split loom BRIDGE cover to the plastic white plug and into the trunk
o. Secure the power wire at various points using wire tires to avoid future rattles
p. Reinstall the glove box, passenger kick panel, front passenger side door jamb cover, rear passenger side door jamb cover, rear seat back, and lower rear seat cushion.

Power wire coming down from rubber grommet behind glove box to the kick panel area


Front door jam


Wires exiting B-pillar to rear door jam


BRIDGE wire housing from rear door jamb to rear wheel well


Large white plastic plug


Power wire running up the wheel well to the large white plastic plug



In the trunk
a. Remove the trunk light
b. Remove the Trunk front finisher (trunk ceiling cover) using the pop clips; The farthest underside of it is held on with staples. Yeah, staples.
c. Pull the power wire through large white plastic plug into the trunk
d. Locate a suitable location to attach a ground cable to the vehicles body;
e. If your amplifier does not accept Speaker-level and line-level inputs directly (which is cool if it does) connect a Line-Output-Converter aka a LOC as directed by its instructions to a speaker wires. I connected to the factory subwoofers wires.
f. Connect the 12V power wire, the ground, and a remote turn-on wire to the amplifier
g. IF using a LOC connect a set of RCA wires from it to the amplifiers input connections.
h. Connect speaker wires from the amplifier to the new subwoofer enclosure.
i. Test the system
j. Locate the factory BOSE amplifier under the driver sider / left rear deck and snip the Rear Microphone Light Green wire – Be sure to ONLY cut this single wire and to leave enough wire that it can be reconnected later if you wish to do so
k. Reinstall the Trunk front finisher
l. Mount your Amplifier, Subwoofer Enclosure, etc. wherever you see fit.
m. Tune and Enjoy.

DONE!

Trunk front finisher (trunk ceiling cover) removal


Power cable entering the trunk through the large white plastic plug


LOC wires tapped into OEM subwoofer wire


BOSE Amp connector diagram – same on both BOSE systems


Rear active noise control microphone negative wire cut

Some notes and fun facts about my installation

What I used:
Elemental Designs (RIP) 13Ov.2 12” DVC Subwoofer
Kenwood KAC-X10D 600W RMS Class D Amplifier
PAC Trunk-LOC
Generic Amp Kit from Amazon

My subwoofer, amplifier, and LOC are all 8+ years old and were installed in my previous vehicle in the exact same configuration for 7 years. Saving and using these kept my cost way down. I am not looking to impress or set off car alarms so new or flashy components were not necessary for my install. Purely function over form, same as in my last car.

I installed the cheapo amp-kit fuse box and pretty much hate it. I plan on taking it out and putting in my trusty old Monster cable unit. My Monster Cable 100-amp circuit breaker is close to 15 years old. Ha! It still looks way cleaner than any of the current offerings.

Amp Kit Fuse Block


The main power cable was installed into the cabin at the same time as my DRL setup was since I had to run wires from the cabin to the engine compartment for both. It was left in place on the passenger floor until I had time to complete the rest of the install. Saved me a little time and effort with pulling wires and removing parts.

My amplifier included a remote Gain and frequency adjustment knob. Like most amplifier remote knobs it uses a standard RJ11 (home phone) cable so I ran one from the glove box area to the trunk along with the power cable. I installed this knob near the drivers shin where it is easy to access but out of the way.

Amplifier Gain and Frequency remote knob



I located a welded in nut just below the large white plastic plug. I found a bolt that it and attached my ground cable there.

Ground cable


I ran a remote power wire from the glove box area too but decided not to use it since my LOC has a built remote turn on that is triggered by sound coming into the speaker

I installed my amplifier under the rear deck (same as my last car) to save space and keep the almost invisible look. To do this I first measure, cut, routed a channel where necessary, painted, and then installed a slab of MDF board to the underside of the rear deck. My amplifier barely fit. A newer model Class-D amplifier would fit much easier. I then bolted up the amplifier to this board. I had to clearance (cut out) some of the Trunk front finisher (trunk ceiling cover) so that the amplifier would fit. This served two purposes – so the amp would fit and also so it can breathe better.

MDF AMP Mount



Amplifier installed under the rear deck



The LOC was installed very close to the amp and fits under the Trunk front finisher (trunk ceiling cover) with no issue.

LOC mounted with 3M double stick tape


I started to design two boxes when I decided to install the subwoofer. The first would include fiberglass’ing in its construction which is fun but was a little unappealing right now given my available time and the rain that has finally arrived in Cali. It’s not a hard process and I have done it before, and actually have a bunch of fiberglass mat still, but I decided against it for now. The second was an all wood odd shaped freak that would fit as far back as possible and take up as little space as possible while still allowing me access to the pass through. It made it as far as cardboard mock-up before being abandoned.

Cardboard mockup of subwoofer box concept


I happened across a shallow mount prefab box at Best Buy that was the perfect width to fit between the wheel wells in the trunk. On top of this it was the correct internal volume for my subwoofer slot ported as it comes or if I seal it up. Awesome. Only the mounting depth would be an issue but I had an idea for that so I grabbed it. It was just too good of a lazy solution for me to pass up. It gets me going now and I can still come back later when time and weather are more favorable and do something else.

METRA Prefab Speaker box


To resolve the mounting depth issue I cut a 3/4 MDF board to fit onto subwoofer box and act as a spacer. This would add enough room for the subwoofer to comfortably fit in the enclosure. I routed it out to match the enclosures subwoofer opening and to smooth the outer edges of it and then hit it with some paint I had handy to seal the wood from moisture – again, I was only aiming for function so don’t judge my blue. I cut the carpet back just a bit smaller then this wood spacer routed the back of the spaced so that it would pinch the carpet. I then glued, clamped, and screwed the spacer to the box. Wood glue forms a very permanent bond once dried so only four screws were used and left in place.

Subwoofer hole


Back side


Finished Product










Future false wall ideas





So far so good. This subwoofer sounds great and gets low when I want it to so I am a happy motorist.

Love the detailed pictures! Thanks much,

Z

I'm gonna request your name be changed to "M_DIY_GUY". Good work as always, sir. I'll definitely be referencing this! Also, added to FAQ.

One question though, maybe I missed it while skimming...why are we cutting the rear microphone wire?

Round of applause to you sir!!!

Wow a that's a very thorough write up! I like how concealed the sub looks, couldn't even tell that there is a cover back there. The Infiniti emblem is a nice touch

^^ That's a photoshop idea of what he wants to do.

szh wrote:Love the detailed pictures! Thanks much,

Z

Thanks!

IlyaKol wrote:I'm gonna request your name be changed to "M_DIY_GUY". Good work as always, sir. I'll definitely be referencing this! Also, added to FAQ.

One question though, maybe I missed it while skimming...why are we cutting the rear microphone wire?

The cars ACN (Active Noice Control) uses a front and rear microphone to listen for engine and drive train noise. It then feeds reverse noise into the sound system (including rear OEM subwoofer) to cancel out the cars noise.

Because we tap the OEM subwoofer for sound the reverse noise is played through the new subwoofer which results in the sound being poor and sloppy. I also experience VERY loud humming from the new subwoofer anytime the car was at a stop. Snipping the rear microphone fixed it and gave me nice tight bass.

Gotcha. Sucks we have to do that.

infinitedrift wrote:Round of applause to you sir!!!

Thanks!

CRV_33 wrote:Wow a that's a very thorough write up! I like how concealed the sub looks, couldn't even tell that there is a cover back there. The Infiniti emblem is a nice touch

IlyaKol wrote:^^ That's a photoshop idea of what he wants to do.

Correct. Just an idea of what is to come.

Great write-up as always, Debonair. I have a subwoofer project in the works and will try to post pics soon.

THIS WAS A GREAT WRITE UP. It's winter time in Chicago so I'm not doing anything until the winter breaks. Questions for you..

1. What size sub did you go with? I have some old 15s, of course I would only use one, but what were the internal dimensions needed for the sub?

2. How is trunk rattle? Did you have to sound deaden it?

I have some old JL 15w6s, what it would cost to get one repaired is equal to some of the smaller subs today. I already have my amp and an audio control line out converter for the sub. After your write, I'm just waiting on some warm weather...

AGAIN THANK YOU FOR THIS WRITE UP...

reggiebrown40 wrote:Great write-up as always, Debonair. I have a subwoofer project in the works and will try to post pics soon.

Thanks! I look forward to seeing it. Any hints as to what you are putting in?

Darthswan wrote:THIS WAS A GREAT WRITE UP. It's winter time in Chicago so I'm not doing anything until the winter breaks. Questions for you..

1. What size sub did you go with? I have some old 15s, of course I would only use one, but what were the internal dimensions needed for the sub?

2. How is trunk rattle? Did you have to sound deaden it?

I have some old JL 15w6s, what it would cost to get one repaired is equal to some of the smaller subs today. I already have my amp and an audio control line out converter for the sub. After your write, I'm just waiting on some warm weather...

AGAIN THANK YOU FOR THIS WRITE UP...

Thank you! I enjoy writing these up which is probobly pretty obvious by now.

1. I am running a 12"

1B. My sub calls for 1.00cF for a sealed enclosure or 1.2-1.5 for a ported enclosure. I also needed to know the mounting depth when picking / constructing / modifying an enclosure.

2. I do not hear any rattles yet but I honestly have not been outside the vehicle when it is turned up. No deadener installed yet but we will see.

NIce! I used to run a 13w6 a LONG time ago. I loved that subwoofer. I look forward too seeing your install.

Debonair wrote:

Darthswan wrote:THIS WAS A GREAT WRITE UP. It's winter time in Chicago so I'm not doing anything until the winter breaks. Questions for you..

1. What size sub did you go with? I have some old 15s, of course I would only use one, but what were the internal dimensions needed for the sub?

2. How is trunk rattle? Did you have to sound deaden it?

I have some old JL 15w6s, what it would cost to get one repaired is equal to some of the smaller subs today. I already have my amp and an audio control line out converter for the sub. After your write, I'm just waiting on some warm weather...

AGAIN THANK YOU FOR THIS WRITE UP...

Thank you! I enjoy writing these up which is probobly pretty obvious by now.

1. I am running a 12"

1B. My sub calls for 1.00cF for a sealed enclosure or 1.2-1.5 for a ported enclosure. I also needed to know the mounting depth when picking / constructing / modifying an enclosure.

2. I do not hear any rattles yet but I honestly have not been outside the vehicle when it is turned up. No deadener installed yet but we will see.

NIce! I used to run a 13w6 a LONG time ago. I loved that subwoofer. I look forward too seeing your install.

The 15w6 requires a sealed box of 1.25 cF. It will cost me $195 to get it repaired with a 2 year warranty with it. I can't beat that anywhere. I'm debating if I really want to loose 9 inches of trunk space. I can construct or have a box built to fit as close as possible.

Another question with mounting of the amplifier.

1. Is the amp mounted upside-down? If so, how do you effectively dissipate the heat?

I have an old Punch 200 that I used to power the 2 15"s. So I know I won't need all of that power for the one sub, but it's good to have it there. I know for the Punch, mounting it upside-down doesn't work to well for this amp(due to their heatsinks).

2. What was the dimension of the amplifier you used?

3. Is it enough room behind the covering to mount the amp?

Thanks for the answers, just random questions that come across my mind as I do my homework.

TL;DR lol
Awesome write up. If I ever have the need to install a sub, I know where I'm going

Darthswan wrote:The 15w6 requires a sealed box of 1.25 cF. It will cost me $195 to get it repaired with a 2 year warranty with it. I can't beat that anywhere. I'm debating if I really want to loose 9 inches of trunk space. I can construct or have a box built to fit as close as possible.

Another question with mounting of the amplifier.

1. Is the amp mounted upside-down? If so, how do you effectively dissipate the heat?

I have an old Punch 200 that I used to power the 2 15"s. So I know I won't need all of that power for the one sub, but it's good to have it there. I know for the Punch, mounting it upside-down doesn't work to well for this amp(due to their heatsinks).

2. What was the dimension of the amplifier you used?

3. Is it enough room behind the covering to mount the amp?

Thanks for the answers, just random questions that come across my mind as I do my homework.

1. Yep, it's upside down. That was a big point of concern (and resulted in lots or warning) for people when I installed it in my Lexus. This was a big reason why I chose this particular amplifier. It uses the whole body as a heat sink and has an internal fan (I think) that moves the air through the unit. It was installed and ran this way for seven years with no issues, no shut downs.

2. 12" x 11". Current class-D amplifiers with the same output are smaller. I considered getting the the Kicker - CX Series CX600.1 if my amp did not fit since it has the same 600w RMS as my amp and is only 8" x 7".

3. Behind the upper cover that I cut? No, not unless it is very flat and small.

Debonair wrote:

reggiebrown40 wrote:Great write-up as always, Debonair. I have a subwoofer project in the works and will try to post pics soon.

Thanks! I look forward to seeing it. Any hints as to what you are putting in?

I'm putting a Resonant Engineering XXX 12 inch sub in a custom fiberglass box I've been building for months as time permits.

Here's a teaser pic:

https://www.flickr.com/photos/22693517@ ... en-public/

reggiebrown40 wrote:I'm putting a Resonant Engineering XXX 12 inch sub in a custom fiberglass box I've been building for months as time permits.

Here's a teaser pic:

https://www.flickr.com/photos/22693517@ ... en-public/

Nice work on the box so far! That's a monster, power hungry subwoofer too. I'm excited to see how it turns out.

Nice write up. I didn't have to cut the ACN mic when I installed mine, I think my LOC canceled that extra signal on its own

Debonair wrote:

reggiebrown40 wrote:I'm putting a Resonant Engineering XXX 12 inch sub in a custom fiberglass box I've been building for months as time permits.

Here's a teaser pic:

https://www.flickr.com/photos/22693517@ ... en-public/

Nice work on the box so far! That's a monster, power hungry subwoofer too. I'm excited to see how it turns out.

Good to see you know your subs, bro. It is a BEAST but it's also an SQ sub. The weather on the east coast has been great this month so I've had a chance to do more work. Hopefully I can get more done this weekend.

Thank u sir. Ill be doing this. Just got a '13 m37x a week ago. Ill be moving my sub and amp from my old car over as well. Can you tell me which PAC i need? My old pac in my chrysler 300 connected right at the radio and i could run rca wires right from the deck to the trunk.

Also is that a oem trunk mat? Made for the M?

TreyhunnaM37x wrote:Thank u sir. Ill be doing this. Just got a '13 m37x a week ago. Ill be moving my sub and amp from my old car over as well. Can you tell me which PAC i need? My old pac in my chrysler 300 connected right at the radio and i could run rca wires right from the deck to the trunk.

Any of them should work. They have updated it 4 or 5 times since I bought mine. The current model is the PAC LP7-2. You can hook them up anywhere there is speaker wires; at the head unit or In the trunk. Most people hook up in the trunk so that they do not have to run RCA's very far. My RCA's run about 12 inches.

There are other options too like the Audio Control LC2i and others.

TreyhunnaM37x wrote:Also is that a oem trunk mat? Made for the M?

Yep, OEM trunk mat. $45 shipped on eBay which was a steal. They are going for $70 now I think. Just search "OEM trunk mat m37"

Any particular reason you went with forward facing, opposed to rear facing for the subs?

Nope. But the box is not bolted down so I am going to be repositioning it when I have time to see how I like it best. Most cars do sound best when he backwards. For now I like that it is real inconspicuous when I open the trunk.

That's what I was wondering about. I like the way that it looks, also. In the past, I've always had them rear firing. Your write up as struck a nerve. You have me in the garage eye options for mounting my sub. I don't want to start pulling stuff down yet, I'm not ready to start.

Thank you for this write up..

Debonair wrote:

TreyhunnaM37x wrote:Thank u sir. Ill be doing this. Just got a '13 m37x a week ago. Ill be moving my sub and amp from my old car over as well. Can you tell me which PAC i need? My old pac in my chrysler 300 connected right at the radio and i could run rca wires right from the deck to the trunk.

Any of them should work. They have updated it 4 or 5 times since I bought mine. The current model is the PAC LP7-2. You can hook them up anywhere there is speaker wires; at the head unit or In the trunk. Most people hook up in the trunk so that they do not have to run RCA's very far. My RCA's run about 12 inches.

There are other options too like the Audio Control LC2i and others.

TreyhunnaM37x wrote:Also is that a oem trunk mat? Made for the M?

Yep, OEM trunk mat. $45 shipped on eBay which was a steal. They are going for $70 now I think. Just search "OEM trunk mat m37"

Thank you sir ordered both off ebay.

Darthswan wrote:That's what I was wondering about. I like the way that it looks, also. In the past, I've always had them rear firing. Your write up as struck a nerve. You have me in the garage eye options for mounting my sub. I don't want to start pulling stuff down yet, I'm not ready to start.

Thank you for this write up..

Haha. Got you started, no turning back now. You are welcome.

TreyhunnaM37x wrote:Thank you sir ordered both off ebay.

You are welcome.

great call on cutting the active noise cord, Started riding and got the subwoofer hum. Had no idea what was wrong. was gonna tear all my wiring out and start again , then I remembered something about cutting a cord. I came back and read more thoroughly and realized I had the same issue. A quick snip and the hum was gone.

A: How did you figure this out?!

B: what does this break as far as how the OEM sound system works? (i keep the bose/infiniti pilot thing turned off)