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46 Posts
Discussion Starter #1
Copied over from my blog, didn't want everyone to have to go somewhere else to see the information, please forgive any formatting issues. Some of the images are kind of smaller, larger copies can be found over on the blog (link in my sig) or I can post them up here if you'd like.

Between phases of the project, the head unit in my daily died. Not wanting to spend money, I pulled the one out of the Miata and installed it in the truck.

Flash forward six months, the Miata project picks back up and I'm down to just a set of 6.5's in the door. No source unit, no rear fill, no tunes. Not optimal.

After a little research, I decided to use my Droid X as the source unit. The car dock was cheap, it's easy to get signal out of it and there are some nice Car Home replacement applications that provide an easy to use interface. It also gave me things like navigation and internet access for just the price of the car dock.

There are a few design considerations that needed to be accounted for:
  • Volume control - the phones controls were not that easy to adjust without looking at the device
  • Ease of access - The phone needed to be close enough to be used with my right hand near the shift lever
  • Sound adjustment - Figured this out during version 1.0 of the system, the phone has no built in EQ
  • Vibration - Another 1.0 bug, the suction cup mount on the car dock allowed the phone to vibrate, a lot
  • Bass - Wanted more then I was getting, needed to figure out how to add the subs without adding lots of weight
  • Power control - Needed to be able to turn off any of the devices (including voltmeter)
  • Cosmetics - It isn't a show car but the end result needed to be decent, no ugly box, no hole in dash
The first problem turned out to be pretty easy to solve. There is a PAC adapter that works as an inline gain control for the RCA's. Signal goes from your source to the PAC adapter and from there to the amp. Easy except the box surrounding it is ugly and it's meant to be screwed into something. I decided the best idea was to work it into the panel I was building to blank out the hole in the dash where the stereo used to go.

List of components:
  • Pioneer 6.5 full range speakers (doors, came with the car)
  • Polk 6.5 components (left over from another project)
  • Planet Audio Anarchy amplifier
  • PAC LC1 remote volume control
  • Cheap 8" subs (they're good, but not name brand)
  • Pyramid 709EX EQ (decent but get a better one, very susceptible to engine whine)
  • 1/2" MDF</li><li>Black carpet
  • Various screws, wires, fuze blocks, connectors, etc (left over from other projects)
  • Stinger voltmeter (looks cool, left over from another project)
  • 3 large switches (1.0 switches were smaller, felt cheap, were hard to toggle, got bigger ones, added covers)
As you can see, I was trying not to break the bank with this install. I wanted decent sound but, with as much road noise as you get in a Miata, audiophile level gear would have been wasted (and not really in the spirit of this project).

Here's the final layout:

Not an overly complicated system. The hard part was going to be fitting the subwoofers, amplifier, EQ and components in the location formerly taken by the top (wanted to keep the weight in the middle of the car).

It took a few tries but, eventually, I figured out a cabinet design that would work and allow the speakers about a cubic foot each. That, and some poly fill, would allow for enough air movement for decent sound and still fit into the limited area I had to work with.

The fill panel for the dash board was created out of a sheet of ABS and screwed to the stock mounting points on the backside of the console (I also added some side supports since the panel would get some pressure applied to the bottom corner when the switches were flipped).

Switches, from left to right, are amp/EQ power, voltmeter power, phone power (the "jet fighter" covers are just for fun). Originally, there were three, much smaller, switches but they just didn't feel right and were easy to miss in the dark.

To get the PAC adapter mounted was mounted by removing the main housing, running the adapter through the ABS panel, then securing the main body back in place on the other side.

The next challenge was the phone dock (and I ended up zapping my X during this build and had to go get an X2, win?) It had been mounted on the windshield but it vibrated so much I was worried it would damage the phone.</div>

After looking around a bit, I came up with the idea of mounting it next to the console but wasn't, initially, sure how to do it.

After some failed attempts, I took a look at the small map light mounted in the dashboard. It hadn't worked in years and it looked about the right size to re-purpose as a mount.

So that's exactly what I did. I took removed the wiring harness, dremeled a large hole through the map light, then took the dock apart and ran the base through the hole, securing it with a zip-tie (around the shaft of the base) on the other side.

It's not perfect, and is at the top of the list of parts to get replaced (the dock tends to rotate a bit), but works well for now.

The final part of the build was the speaker cabinet/amp rack. This was a pain to build (I know, looks simple, right?), I wasted a bunch of wood experimenting (though I never used up my initial supply) but, in the end, it looks exactly like my first sketches.

Once everything was back together, I had knocked everything off my initial list but came up with a few new issues:
  • Engine whine, the EQ has it - Everything is grounded together and they all run back to the battery but, for some reason, if I turn the power on to the phone (or even plug the charger into the phone with the switch off), I get whine. This didn't happen before the EQ and I think I can solve it with an inline noise reducer
  • Dock likes to pivot around in it's mount - As mentioned above, this isn't a huge problem and is pretty easy to solve. I'm going to make a custom mount to replace what's left of the map light, remove the base of the dock, and mount the remaining parts to the new mount. This should give a solid foundation for the phone and fix this problem
  • Remote gain control for amp not mounted - This is an easy fix, just haven't gotten around to it
  • Subs need grills - Just need to order them

The end result was worth the trouble. The stereo is easy to hear on the highway (even at 80+ with the windows down), the little subs have plenty of punch for the little car and everything is easy to get to. The over-sized controls make it easy to use without ever taking your eyes off the road and the few pieces someone would want to steal are buried in the back (the seats have to be removed to get the box out) and bolted to the studs used to hold the top in.

It's fun, mostly secure and fun to play with though not perfect. Sounds perfect for a project Miata, no?

46 Posts
Discussion Starter #3
Here you go:

Not very pretty but it's hidden behind the mount so it's not really visible.

Still want to replace it though, the little bit of play it has moves the screen just far enough to the right that I miss the "next" button sometimes.


495 Posts
:eek:WOW:eek: Nice write up man. This is really nice. How good is the Planet Audio Anarchy amplifier? I never heard of them before. I am going to replace the Bose system in my NB. I am thinking of going headless and doing something very similar. How did you get the volume control wired up and more details on wiring.

46 Posts
Discussion Starter #5
:eek:WOW:eek: Nice write up man. This is really nice. How good is the Planet Audio Anarchy amplifier? I never heard of them before. I am going to replace the Bose system in my NB. I am thinking of going headless and doing something very similar. How did you get the volume control wired up and more details on wiring.
Thanks. :)

I hadn't heard of Planet Audio before I purchased this one. I was looking for a 5-channel amp that wasn't to expensive and this one had really good reviews on Amazon (and was less then $200, shipped). So far it's run like a champ. It pushes the 8's (which or run in series on channel 5) just fine, came with the bass-channel gain knob, has nice metal end caps to hide the wires and has cool blue lights (not really important but they do look cool).

The volume knob is about as easy as you get, it's got two seats of RCA inputs on the back of it, one marked "IN" and another marked "OUT". There isn't any power to it, so no lights, but it's really easy to wire up.

I complicated the install by placing it in the panel. If you weren't worried about that, you can mount it on the bottom of something with the mounts molded onto the adapters chassis.

The rest of the system is really straight forward:
  • Channels 1 and 2 are for the door speakers
  • Channel 3 and 4 are rear speakers
  • Power for the amp comes straight from the battery
  • All of the electronics are grounded to the same wire as the amp, that wire goes back to the battery
  • 12V power to the first two switches on the panel comes from the radio harnesses switched circuit
  • Power for the third switch comes from the radio harnesses constant power circuit
  • Switch one works as the remote and power wire for the EQ, the EQ has a remote circuit that tells the amp to turn on
  • Remote gain knob has a phone-cable wire and is run into the center console, the control is just sitting in there right now
  • All wires for the speakers in the back (and all the RCA's from the EQ to the amp) are in the box under the 6.5" components
  • Signal RCA's are run next to the center console, along with signal wires for the door speakers
  • Door speaker signal wires are connected to the factory harness
  • All of the circuits connecting to the car (door speakers, power) are connected through a radio adapter harness I had left over from the last head unit install, so it can be removed easily
  • I installed a 12V power outlet behind the center console, power for the phone comes from there through a regular phone charger
That's about it. I know it looks like a long list but it's really not that bad. Most of it is contained in the speaker box or behind the console. Only wires under the carpet are signal for the doors and one set of RCA's. So the install was pretty straight forward once it came time.

The hardest part of the wiring was jogging all the wires through the box and up to the amp, then sliding them back in when I dropped the amp in place. Well, not really so much "hard" as "fiddly". It's a tight space and everything wanted to get in everything else's way. :)
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