Wednesday, March 3, 2021

LX470 - Nakamichi Stereo Upgrade.

The 2000 LX470 I got came equipped with the Nakamichi sound system. Although it still sounded good, I definitely wanted to upgrade the head unit to bring it to the 21st century. Android Auto was the main feature I wanted along with a rear view camera and better sound. 

With those goals I figured it was better to go ahead and change all the components. Head unit, factory amplifier, subwoofer. along with the front and rear speakers. 919 Motorsports in Raleigh, NC is my go to stereo shop. Shaun has always helped pointing me in the right direction for all my stereo needs.

This is a list of components I ended up going with.

Kenwood DMX706S
Arc Audio Black Subwoofer (Black 10V2 D2)
Front Speakers - 5.25" - Hertz DSK 130.3
Rear Speakers - 5.25" - Polk db522
Polk PA  D5000.5 - 5 channel amp
HPM 4GA Power wire
HPM 16GA Speaker wire
5 channel - RCA 
Kilmat deadening 80 mil (36ft x 2)
Noico closed cell foam 150 mil (36ft x 2)
1/4" closed cell foam 30"x60"
5.25" fast ring
Scosche MDAB - Antenna adapter
Metra 40-UV43 - Antenna Y adapter
LX470 Faceplate
Rear view camera
Custom Sub woofer box

When looking at the factory front and rear speakers the Nakamichi system speakers was in a ported enclosure. It is really well designed and so wanted to use the enclosure. Modified it a bit by adding few strips to mass load it to reduce vibrations and making a foam ring where the speaker would sit to help seal it better and again reduce any vibration it might or might not have.

I did things in stages and took me about two weeks. A couple of hours in the evening after work and on weekends when I could. 


Since I had to remove all the panels I felt it was the best time to go ahead and add some deadening and insulation. I don't think any of these panels have come off in 20 years of it's existence. The amount of dirt/hair that accumulates is pretty disgusting. Cleaned everything in and around each part that came out along with the part itself. A clean start is the best start I feel.

The door panels got a layer of 150mil closed cell foam insulation after a wipe down of isopropyl alcohol for better product adherence. 

The doors got some sound deadening. I didn't do 100% coverage because it's been proven that anything over 30% coverage yields diminishing returns. I've tried this out in the past did 100% on one door and about 50% on the other, the difference in the knock test was very minimal so really didn't think the added weight and cost is not worth it.

Might not be very clear but behind the plastic on the outer skin of door there is about 30% coverage of the Kilmat deadening. behind the speaker enclosure on top of the deadening I added some of the closed cell foam as well. The above picture is how everything looks on the door. All the wires were soldered, heat shrunk, loomed with Tesa tape etc. All the factory plugs were utilized. The Hertz 130.3 has a small crossover so it fit right behind the harness junction, I even put it behind the plastic moisture barrier so you don't really notice it unless you look. Looks factory!   


I ended up cutting the factory harness and soldering the Kenwood harness directly. Used the Metra 40-UV43 and Scosche MDAB adapters to utilize both front and rear antennas on the the LX. Also ran RCA cables as well to the amp, the reverse trigger for the head unit got soldered to the reverse signal on the ECU.

Tesa taped and factory sheathing back in place. Keeping it looking OEM.

   The face plate I picked up on Amazon and it was a good fit.

I wrapped the trim in some interior tesa tape to prevent plastic on plastic noises and ca glued it in place.

All the wiring in place.


I don't have a lot of pictures of this but the amp fit under the seat. I removed the factory amp and it sit perfectly in its place. I cut off the speaker output harness and used a deutsch connector to create a quick disconnect harness from the amp to the factory wiring. The white and blue wire have to be connected together and the two grey wires from the orange connector pictured below have to be connected as well to bypass the factory amp so the aftermarket amp can turn on. The power, ground, amp turn on wire etc all have ferrule connectors to prevent any stray strands issues.


With all the wiring out of the way moved on to the trunk where I wanted to dampen and insulate it as well. 

Here is a quick knock test, the doors were dampened and insulated whereas the quarter panels weren't. 

Removed the panels and rear carpet and cleaned everything first. Wiped the interior down with isopropyl alcohol to remove any grease etc to help everything adhere better.

The wheel and quarter panel got some kilmat dampening as the first layer, again not full coverage.

After the kilmat, the wheel wells got a layer of the closed cell foam and the quarter panels got an inch of thermal foam with closed cell foam. I forgot where I got it from it was left over from another install on my other car, yay hoarding! It has a self adhesive backing that stuck well with like the thinner closed cell foam on the wheel well. 

The quarter panel panels got a layer of 150mil closed cell foam insulation after a wipe down of isopropyl alcohol as well. The panels went back on without any issues. It was a snug fit though with the extra foam on the panels and wheel wells. 

The floor just got a layer of 1/4" thick closed cell foam. I didn't put any kilmat under because the floor had a lot of ridges that help with dampening and it also had some factory dampening material which I thought was enough. 


This was a little bit of a pain. I wanted a factory style camera in a factory like location and the best location I thought of was between the license plate lights. The video signal cable and the reverse trigger got ran from the front, along the passenger side. The sub woofer wiring also joined from under the seat. All the wiring was ran and attached along with the factory wiring to keep everything looking factory. Down the passenger side, across the second row under the carpet into the driver side rear quarter panel. This is unfortunately where the 20ft cable supplied with the camera ended. Got a female to male cable to extend the video cable. This cable with the reverse trigger ran up the quarter panel, into the grommet into the tailgate, down the tail gate and then followed the license plate lighting wires.


Drilled a quarter inch hole to mount the camera. This cannot be accessed with the trim on the inside removed. Had to pop the license plate light out and basically use my fingers to guide the nut onto the mounting screw. Well, after a few choice words and multiple use of the magnet I got it on. Only to find out that the ridge in front of the camera blocks visibility.

Had a 1/8" abs sheet that I ended up gluing multiple layers together and trimming to slide under the camera. 

I ended up needing to angle the camera a little as well. Made a wedge using the same process and sanded it down to get the right angle.


I wanted to use an ARC Aduio 10" sub that I bought for another vehicle but this would work perfectly for what I'm trying to achieve here. It is a 10" sub that required just 0.75cuft in a sealed box. Since I needed a box to get built I had a modular design I wanted to tried to incorporate that into a drawer system so the sub box wouldn't just be a standalone box in the trunk. 

Used an online calculator to figure out what dimensions the box should be so I can't take credit for that. I just needed the box to be a certain height and width to fit into my design. Cut the wood to size and used glue and brad nails to hold everything together. Rounded out the top and side that was facing the seat just to prevent any issues. The 2" hole was cut out for the speaker terminal cup.

Used solder and heat shrink for the wires onto the terminals of the terminal cup. The speaker end wires got ferrule connectors and heat shrink to avoid any stray strand issues. 

Used some closed cell foam tape around the speakers and the terminal cup to ensure a good seal. Also used some flex glue on all the internal joints, again to ensure a good seal.

This sub box snowballed into me having to create a drawer system around it to make everything utilitarian. I didn't want to just have a sub box taking up room in the trunk. Super happy with how everything turned out. 

-AJ Abraham

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1 comment:

  1. Question for you about the speaker encloser...what are the grey studs with red inside for?