How-to Guide
How to Add a Subwoofer to an Android Head Unit
Quick answer
The subwoofer output is A16 on Harness A. It breaks out to two green RCA plugs on the harness, both carrying the subwoofer signal. It's a dedicated output, so you keep both the front and rear pre-out pairs. The turn-on lead is the blue wire on A1, the same one you'd use for an external amplifier.
What this gives you
Low end a door speaker can't produce, and you don't give up any of the four channels feeding the rest of the car. On a diesel 70 Series, most of what you lose on the highway is the bottom of the music, because that's the part sitting under the engine and tyre noise.
Before you start
- Harness A, the front audio pre-out and AUX harness. It comes with your unit.
- A powered subwoofer, or a passive sub and its own amplifier.
- One or two RCA leads, depending on whether your sub takes a stereo or a single input.
- A power and earth run to the sub already sorted, since the head unit only gives you signal.
Step by step
- Find A16 on Harness A
A16 is the subwoofer output. It breaks out to two green RCA plugs on the harness, both carrying the subwoofer signal. The green is how you tell them apart from the white and red pre-out plugs on the same harness.
- Run it to the subwoofer input
If your sub or sub amplifier has two inputs, it takes both green plugs. If it takes a single input, use either of them. They carry the same signal, so you can't get left and right the wrong way round.
- Run the turn-on lead
A1 on Harness A is the external amplifier control and the wire is blue. Take it to the remote terminal on your powered subwoofer or sub amplifier. This is the wire that stops you leaving the sub powered up all night.
- Set the crossover on the head unit
The unit has its own subwoofer crossover and level control. Set the crossover first so you're only asking the sub for the bottom end, then set the level.
- Set the sub gain last, with everything else already set
Get the rest of the system where you want it first. Then bring the sub up until it fills in underneath rather than sitting on top. A sub you can point at in the mix is set too high.
- Check it against a track you know well
A track with real low end you've heard a hundred times tells you more than a bass test tone. You already know what it's meant to sound like.
If it does not work
- If you get no output at all, check the green plugs are on A16 and not on the AUX audio input on A5 and A3, which are also on Harness A.
- If the sub stays on with the ignition off, you've got the turn-on lead on a permanent supply instead of A1.
- If the sub thumps on power up or power down, that's usually the turn-on lead timing at the amplifier, not the head unit output.
- If it's boomy and one note, try the sub in a different spot before you touch the settings. Position changes low end more than any control does.
Worth knowing
The sub output is separate from the four pre-outs and from the 5.1 centre channel on C2, so you can run a subwoofer, a four channel amplifier and a centre channel at once off the supplied harnesses.
Still need help?
Tell us your vehicle and what you're seeing on screen, and we can point you to the right step.