Introduction: Custom Stereo Installation NO HEAD UNIT

About: I Make Stuff

The following is the process in which i built a custom stereo for my 1967 Citroen Ami6.

Because of modifications to the car by previous owners i was able to take some liberties in the installation but i wanted the install to be largely unobtrusive on the overall appearance of the car. I have a long history of installing absurd stereos in places they don't necessarily belong but this was the first time i was attempting to hide the majority of the install. I decided that if possible i wanted to avoid running a head unit all together since there is nothing more out of place in a vintage car than a modern digital head unit with flashing lights and a whacky EQ visualization.

A long time ago i knew a lot more about what I'm doing, i understood amps, ohms, watts, etc. and the fine details of putting a system together. Not so much anymore, mostly i just do things the way i remember and guess when i don't. This whole system might seem a little hacked together and to some of you it might even seem flat out wrong. It was all an experiment and i am very happy with the results.

Please use this information as proof of concept only, i am not educated enough on what I've done to say with absolute certainty that you won't electrocute yourself, burn down your car or otherwise cause serious harm or damage your body or property.

Also please feel free to tell me why I should have been killed or maimed during my own installation process if you notice any glaring errors.

Step 1: What Are We Working With

A vintage French Car.

As you may note, this car has a somewhat unique aesthetic and you might agree it shouldn't be disturbed with various modern components.

One of the attached images is from a french magazine in which the car was featured, unfortunately this is the only image i have showing the state of the door cards when i received them. The drivers side card had already been cut for a speaker and all four door cards were extremely warped and the vinyl was peeling and delaminating.

I knew i could rebuild the doorcards but someone had already cut one of them up so it would never be near original again, this was the impetus behind the project. A doorcard with a hole for a speaker needs a speaker!!!

So now i knew i was willing to put front speakers in and i didn't want a head unit.

I took some measurements around the rest of the car and decided i could get some shallow  components in the front door and a set of 4x10"s under the backseat in a custom box along with  a 10" sub and amp behind the backseat.
I just needed to find the right shallow sub, either an under-seat box or something meant for behind the seat of a pickup truck.

But first lets figure out if ditching the head unit is feasible.

Step 2: No Head Unit???

The first thing i found was a 12v ipod/iphone charger with a set of RCA out puts.
This would be the foundation of my project.

This really only gives me a left and right chanel with no real control outside of the ipod.

So we split the signal in to three chanels with simple y connectors.

Now i have three independently controlable channels, that i plan on using for front, rear and subwoofer. I could keep splitting to also gain left and right controls but the entire cabin of the car is tiny so it's possible that even front and rear aren't necessary.
It's also important to note that i was just splitting with existing RCA connectors because i'm lazy, you could certainly cut and splice.

I knew pretty early that i was going to have a lot of wires and crazy connections so i also added a noise filter to cut back on all the engine noise i was likely to pick up.

From there we run each chanel in to a line level controller to create a half assed volume control.

To build an on off switch I got a vintage windshield wiper switch that matches the existing switches in my car, this also allowed for correct switch opperation with a remote line to tap in to the ignition switch as well as a constant power supply

The last thing i added was a vintage matching indicator light that i upgraded with an LED to show when the unit was powered on.

I did a dry run by hooking all of my wires, knobs and switches togehter in a giant convoluted knot and ran the output in to an existing amplifier setup. !!! IT WORKED !!!

The attached image is the diagram of the final install. Maybe it makes sense?

I've also included a render of the 3-d modeled parts along with the stl files for use if anyone would like to reproduce my system.

Step 3: NO HEAD UNIT !!!

Since i now knew it could work the next step was to "Make It Work"

I got my calipers out and started measuring all my bits and pieces, translated that info in to Solidworks and came up with the most condensed box i could that would fit all that junk.

I outputed the 3-d file to a dimension printer and ended up with nice little Not-A-Head-Unit.

I got ahold of some vintage knobs that matched the on off switch and adapted them with another 3d printed part to the line level controllers, i finished the face of the Not-A-Head-Unit with a piece of black acrylic that matched some other high gloss black surfaces in the car. Then mounted the entire assembly under the dash with the ipod connector running up to the parcel shelf above.

Step 4: Door Cards and Front Speakers

The first step was to remove the vinyl from the existing door cards and clean it up, the front cleaned up well with armor all but the backside required scouring with solvent and a scrubbing pad.

Originally the cards were made with a paperboard, felt, vinyl sandwhich that was heat sealed togehter.
I had to use a large amount of spray adhessive, heat gun and elbow grease to strech, stick and secure everything back in place so it looked good. Again, someone had already trashed the door card by cutting it up so i was not too worried about stock materials and process to fix the situation.

I ended up replacing the paper board with a piece of flourescent yellow polycarbonate, this will hopefull better support the weight of the speakers and resist warping due to moisture.

Next i ordered my speakers and again used some modeling software and a 3d printer to produce custom mounts. The doors are very shallow so i used this mount to bump the speakers out 3/4" further in to the cabin. I created two parts, a flanged mount that would convey the weight of the speaker on to the door card, this piece was inserted from the back. And a trim ring to clean up and cover the rough cut in the vinyl, the trim is secured with screws through the back of the mounting plate.

The speaker is then mounted from the outside and the stock speaker grill covers the mounting hardware.

Step 5: Rear Speakers

Since my rear door cards were intact, i simply restored those with a little more attention to materials.
This car has a unique bench seat made with rubber bands and canvas, the seat is just a frame covered in fabric so there is plenty of unused space underneath. this is where i put my rear speakers.

I built a box that would angle the sound up and out from uner the front of the seat, covered the whole thing in vinyl to match the door cards and chopped the ends for free airflow since i didn't remember all the details of ported enclosures. i covered  the open ends with some custom vents again, designed in solidworks and 3d printed.


The only thing left is the Amp and Sub.

Those went in the trunk, upright behind the rear seat, there wasn't really a great place to hide all this so it is fairly conspicuos fortunately the whole assembly looks enough like a flux capacitor that most pepole just assume i drive a time machine.

I also added a capcitor to protect my miniscule and delicate charging system, I think the car originally had an 8 amp alternator, mine has been upgraded to 12 but this is already barely enough to run headlights, wipers and a blinker all at once. So far i've been ok the the charging system seems to hold up with the stereo cranked and the headlights on but if i get stuck at a red light at night you can almost watch the voltage drop. 

The final system consists of:

amp:Kenwood XR-5S 5 channel
capacitor: streetwires zn-1
front: 5.5" kenwood components
rear: 3-way 4x10" kenwoods
sub: 10" pioneer enclosed 10" sub

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