How to build your own NA Miata center console Stereo

Ejecto seat cuz

I hated the radio that came with my car. It was bulky, had a CD player, confusing design, and worst of all, made all my songs sound like I had a blown out bass.

After searching online for a plug and play replacement, I couldn’t find what I was looking for, which was something cheap, simple, and matching the aesthetic of my car. So I built my own

Step 1: Aquire hardware.

Parts

Aluminum stock: https://www.amazon.com/gp/product/B00HRHBB20/
Stereo unit: https://www.amazon.com/gp/product/B07D7XF5GS
Switches: https://www.amazon.com/gp/product/B00ST2AHE0/
Wiring/connectors.

Tools

Multimeter
A ruler or calipers
Drill
Soldering Iron
Some way to cut the aluminum. Will get to that later :)
9v battery
Wire cutters
A stripping tool.

More on the parts:

Aluminum stock — I bought a 3/16th inch aluminum card. I did this thickness so it would be strong, but in hindsight, I could have used thinner, which may have helped with the cutting. You could also use a different material, like wood, carbon fiber, or 3d print something. Aluminum just matched my a e s t h e t i c

Stereo unit — Amazon has quite a few different options for the stereo units. I wanted Auxiliary cable, but you can easily find a bluetooth capable one. I found that the search query “High power Audio Amplifier Board”, works best. You want to make sure that the output wattage is high enough for your speakers to reach their full potential, and that it can be powered by 12v

Step 2: Probe

After getting your materials in, and committing to this project, you will want to see how to actually make it work. This is the hardest part of the process as it is filled with a lot of uncertainty

Take apart the dashboard

Then take off the front console. For the sake of brevity — follow this guide: https://www.youtube.com/watch?v=yveIZqLvddM.
Note: For popping out the vents, I found the most efficient way is to get a stiff wire, and bend the end into a U shape. Stick it into a slot, and then pull back to hopefully get the end to go through a different slot. Then you can yoink it out.

Figure out the stereo wiring

Someone had put an aftermarket radio, and thus aftermarket wiring in mine. Yours may be stock. After doing a quick google, every one of them looks different, so I will show you the steps to figuring out the wiring, because in a 27 y/o car, who knows what previous owners did.

1. Figure out ground — This should be the easiest. It should be a wire that is connected directly to metal, and looks different from the rest.
2. Figure out always on power — You can probe for the voltage of always on, with using the volt meter, using the ground for one end, and then sticking your wire into the different slots in the adapter until you get that 12v
3. Figure out sometimes on power — This is the one that is on only when the key is in and turned one “click”. Do the same probing you did for step 2
4. Figure out the left and right speakers — To do this, grab a 9v battery, and connect the terminals to the different slots using probing wires into the adapter. When you find the right two, the speaker will make a popping noise. This is how you know its good.

Size the hole

I measured the hole for the aluminum panel to be about 4.75”x7.25". However you should re-measure this because this is:

1. Probably wrong
2. Dependent on how you plan on mounting the aluminum — I went with a pressure fit from using the back plastic panel, and the front panel. You could actually screw the panel in if you wanted to, and then you would want it to be bigger, so you could make drill holes in the aluminum for mounting — Again I leave this to the readers discretion, as all Miatas are unique

Step 3: Test

This is the make or break moment. The radio you bought for cheap from Amazon may not work, and more likely, you made a wrong wiring assumption.

To test it simply attach the wires to what you think is what, and see if it plays!

Be careful to only have electricity live for short periods of time when you are directly testing something. Having 12v live on a wire when you are screwing about could contact the circuit board, and fry a component instantly. I have done this before on another project, and it mega blows.

I also recommend getting solid core wires to probe, as you can shape them to exactly the right place.

Having a friend help makes controlling all the wires much more easy — this step may be hard for some of you.

This is a PITA, but is important because you most definitely don’t want to have to re-solder everything.

Step 4: Wire it up

Finished wiring.

After I knew that I was not going back to my old radio, I decided to cut the wires and use the connector, so it was a plug and play solution, and I could do all of my hard soldering work at home.

The wiring was pretty straight forward. I soldered the power wires directly to the board, and then soldered on one of the switches to the radio. This is completely unnecessary, as the power is cut when the key is not in anyway, but figured I give one of the switches a use. (The rest are for later projects)

To wire the neutral, I just stripped the already attached wire to the car, and added an electrical cap. This is so that the radio can be easily removed from the car for future repairs/extensions.

Step 5: Cut aluminum

I had never cut aluminum before, so I naively thought I could cut through it with a metal saw I found at home depot. I could in fact, not. I spent about 30 mins sawing, and saw about a quarter inch of progress.

This was not going to work. I then looked into getting an angle grinder, but it turns out that cutting aluminum with an angle grinder can be dangerous — that is if you use the typical sanding wheel.

I ended up finding a local DIY shop located in the middle of warehouse land, where you can work on your car for $15/hr using any of the tools you want — pretty sweet when you only need that 1 tool once a year.

I went and cut the aluminum to length. I used tape to aid in the line of the cut, but with the grinder, it was extremely hard to keep it straight, so one of the lines came out a little wobbly.

I did a test fit in my car, and to my astonishment it was actually a decent cut.

After cutting it is time to drill the holes.

1. Start by marking the lines where you want the holes to go. These should have padding on the top left and right for functional and aesthetic purposes.
2. Then start drilling with small bits. For the radio ensure everything is lined up.
3. Once they are drilled, bring out the big guns and drill to the size. I guestimated this one and just erred on the side of caution for figuring out the hole sizes.

Step 6: Assembly

1. Put everything in to place, and tighten down all the nuts so it is ultra tight on the board.
2. Then carry the entire assembly to the car, where you can plug in the connector, and then finish grounding the wires.
3. Run a test of the music. It should be loud and clear.
4. Slip her right in
5. It should sit very flush.
6. Put in the trim, and screw it in. Ensure that the aluminum plating isn’t moving.

Step 7: Celebrate

Play whatever song you want at the loudest it can go.

Final product.

The outcome for me was better than expected. The sound quality is pretty good, although lacking on the bass category. This is just because of the way the circuit is equalized, as it has a bass output as well that is unconnected currently. The switches are sweet, but I’m not sure how I feel about the red led. It’s pretty bright and can cause some glare at night. Oh well, feels super rad to flip them.