Running wire, head unit adapters, fuses, and less trunk space all suck. Let’s not do that. Modular setups seem more promising.
A few months ago, I assembled a $6 tube subwoofer that could be used in a house or in a car. I only recently set up my car for this sub. It took an hour. No new head unit required.
There’s only one real compromise to this, only the audio coming from the auxiliary port is sent to the sub. That’s how I listen to music 95% of the time, so no subwoofer with the CD player or radio is fine for me. I tapped into the auxiliary output right next to the cigarette lighter, so I ran power from there. The cigarette lighter is only on when the car is on, so I don’t have to worry about draining the battery when the car is off. There are no power supply issues, as the cigarette lighter supplies 20A, while the sub only draws 4A max.
I started with removing the front section of the center console. It pulls off pretty easily.
Look at the auxiliary input, depress the push tabs on the side and pull it out.
Depress the green push tabs and wiggle out the board.
The pinout is very simple here. I am taking the GND and both channels. This is a mono sub, so knowing which channel is left or right is not important. Just don’t short the channels to each other.
Here are the three wires being pulled off the aux input. Hot glue is your best friend here. Reassemble the unit.
To have volume control and keep the left and right channel separate, you need a dual gang pot, or two separate pots. I didn’t want to spend $8-$10 on a dual gang pot, so I went with two 10K pots I already had. It’s stupider than one pot, but its cheaper and I don’t have to combine the left and right channels.
Update: You can get probably away with one pot pulling the signal from one channel. The impedance of the sub was high enough to not make an audible difference from pulling the signal from just one channel.
Next up, wiring. Everything is terminated with plugs to simplify removal and maintenance. There isn’t much to it, only two sets of wires to run. Enjoy!
If I want to reclaim trunk space, I unplug two wires and remove the sub. I really like being able to remove this sub in under 10 seconds. There are two compromises, first is the power, you are limited to 300W (wiring from cigarette lighter).You could run a power line from the battery to overcome this. Second, the subwoofer won’t work with CDs or radio, just the auxiliary source. Overall, this is a great compromise between ease-of-install, functionality, and sound.