Hey all, back in 2023 I installed a subwoofer in my 2011 i30. It was my first time installing a subwoofer and I found the precious information available on this forum at the time very helpful.
I want to share my experience.
My priority was to use as little boot space as possible, so I built a subwoofer enclosure that fits snugly into the space above the wheel arch in the corner of the boot. This placement does unfortunately block the built in boot light.
Here’s a diagram of the end result, superimposed on the original car.
All the cables going to/from the front of the car were routed along the left hand (passenger) side of the car.
The aftermarket amp next to the factory radio is something I re-used from my previous car. It’s designed to integrate with factory radios and it provides a signal for a subwoofer amp to use. There are other ways to install a subwoofer, which don’t require buying this.
Main components:
Focal “Sub 10 Dual” (10” 250W RMS subwoofer)
Subwoofer enclosure approx. 15 litres internal volume
Vibe Powerbox 400.1M (sub amp)
Vibe Powerbox 65.4M (amp)
Wiring from battery to inside cabinTo be clear, this photo was taken after the entire install was finished. I disconnected my car’s battery before commencing any work and didn’t connect the power wire until the very end.
The power wire goes in under the body panel by the wheel arch and into the passenger footwell through an unused grommet. Thanks to the person who originally posted that clever routing method which I have copied from!
I used 16mm diameter conduit. Larger than 16mm conduit might not fit through that gap. With the bit of black tape I wrapped around it, it is invisible when the bonnet is shut.
I used a 5 metre long power cable between the battery and the sub amp in the boot. There’s a bit of slack at this end, but it’s a different story in the boot! By the time I had stripped the insulation for the terminals, made mistakes and re-cut a few times, I had very little to spare.
The conduit comes through into the wheel arch area. I secured it behind the existing black conduit. I ran the conduit over and down to the far side of the arch.
I cut a hole in the grommet, then fed the power cable through. The hole should be as small as possible to ensure a tight fit.
I put a dip in the power cable, to stop it from ever channeling water into the grommet.
Once I retrieved the power wire inside the passenger footwell (more on that later) and was happy that the lengths of wire either side of the grommet were sufficient, I applied hot glue to reseal the grommet as best I could.
Inside the green circle is the power wire within the grey conduit, barely visible in this photo. Those thin red/blue wires are NOT the power wire!
The power wire had to be pulled through from the void behind that cluster of connector blocks. The power wire and conduit left of the green circle go off to the boot, while the conduit right of the green circle goes up to the glovebox.
The conduit is so handy, highly recommend it to keep everything protected and tidy.
Wiring from front of cabin to boot
The power wire (outside the conduit) and various other cables (inside the conduit) running along by the front door...
then out from behind the the seatbelt pillar trim, then running along by the rear door...
then up by the left wall of the boot.
Encircled in green is a ground terminal with my subwoofer amp’s ground wire connected to it.
I was paranoid about red paint that was covering the surface where the electrical terminal makes contact with the car body, so I sanded the surface to bare metal, screwed the terminal back in place, then sprayed back over the surplus sanded area. Not sure if this measure was necessary and/or wise.
Wires entering the boot - from left to right: bass boost remote control cable, sub amp audio input signal wire pair, sub amp ground wire, sub amp power supply wire, power-on signal wire, subwoofer speaker wire pair.
Not sure what these holes in the carpet were designed for, but they’re perfectly located for this.
I used scrap wood to make a mounting plate for the amp. It comprises two sheets of wood, each a few millimetres thick, the carpet sandwiched in between, with screws holding the sandwich together. The amp is then independently screwed onto the wood. Velcro wasn't an option, it doesn’t stick to this carpet at all.
Wiring from sub amp to subwoofer
Subwoofer speaker cable, coming out from behind the left wall of the boot, across the floor of the boot...
back under the carpet at the right wall of the boot...
then out from a hole in the carpet where the rear seat backrest latch is, into the boot and straight into the enclosure.
I installed this XT90 connector pair so I can disconnect the subwoofer easily. I later wrapped it all in loom tape for subtlety.
Install complete.
Wiring from passenger footwell to centre console
This is the amp which integrates with the factory radio and also talks to the subwoofer amp.
Cables in grey conduit on the left go down to the floor and on towards the boot.
White cable is the bass remote cable. It’s actually repurposed alarm wire. It goes off to the right and down, and emerges next to the cigarette lighter.
The rest of the wires are part of this amp, they go up and right to the radio.
I crimped a RJ9 connector onto the end of the bass remote cable because that is what my bass boost knob needed.
Ignore the wiring/equipment going off to the right of the bass boost knob. It’s unrelated.
My impressionsBear in mind that I don’t have a clue about audio tuning and I’m using a rather small, unproven, not-professionally-made enclosure.
The resulting bass sound is a big step up from the factory speakers. It can get plenty loud, albeit a little unrefined. I find myself using the bass remote more often than I anticipated. I think this is due to a relative increase/decrease in bass volume between some songs. This happens moreso with assorted spotify/youtube playlists and seldom with CDs/albums, where the recordings are more aligned in terms of bass if that makes sense.
Overall I’m quite happy with how this turned out, and I really enjoyed building it. I plan to keep this setup until I either get rid of this car (hopefully a long time away), or stop resisting my curiosity/temptation to try a bigger enclosure.
That’s all!
