I wanted to install the rear shelf subwoofer in my car, which did not have
Bose
, and has an aftermarket stereo. See
this thread
for my starting place. In short the sound system as it was:
Sony XAV AX100 head unit
Pioneer GM-D1004 amplifier
2 x 4 inch Faital Pro full range door speakers
2 x 7 inch Dayton Auto woofers
I wanted the Bose subwoofer because the first Boxster I test drove had the Bose package and I thought it sounded good, and attributed some of that to the rear shelf. It's a powered subwoofer and its literally made for the car, I figured it would be relatively unobtrusive.
Hah!
My best resource for this project was this
thread
where someone put a 987 subwoofer in a 986 Boxster. But it is not very complete. I hope this thread will be a resource if anyone else wants to do this.
Key to making this work: Your headunit needs a sub out that is line level - this is typically a single RCA jack.
First:
The box contains the subwoofers and a pair of full range speakers, also. I opened it up to see what was going on:
Those are Bose 51/4 inch drivers they use everywhere. You can see an "Autobahn" amp which says 100w on the label. Also, I took out one of the full range speakers. It's a bose 2.75 inch speaker and I can't much in the way of specs, but it appears that these are 4 ohm 25 watt speakers. They are NOT powered by the amp - the amp only powers the subwoofers.
So if you want to include them in your plan, you need some speaker level output to connect to them. My head unit has amp line out for front and rear, but it also has 55w x 4 on speaker level. I decided to connect the rear speaker outputs to these speakers.
Wiring of the subwoofer box. There is an
plug
for the subwoofer where it connects to the car.
I did not have the car side plug - I suppose that might be sourced from a junkyard. The pinout for this connector is listed in that 986 thread like this:
1 - Amp power +
2 - Amp power -
3 - Subwoofer remote
4 - Subwoofer +
5 - Subwoofer -
8 - Rear Right -
9 - Rear Right +
10 - Rear Left +
11 - Rear Right - [sic - that should be rear left]
This is a 12 pin connector, and only 9 of the pins are used. Here is how they map:
I would recommend doing your harness work first. I did not and I ended up putting the top in maintenance mode at least a half dozen times. Do the harness outside of the car. If you have a car side connector, great. If not, then it has to be adapted. I wanted to preserve the stock connector and attempted to use the female side of bullet connectors - they are too large even with 18 guage connectors. If I had thought about it enough ahead of time I might have used a 12 pin connector like this one:
But I ended up going with an 8 pin EPS
connector from a computer store:
I had a separate connection for 12v power for the amp.
I ended up cutting the wires to the OEM connector and connecting them to the EPS - you can choose whatever mapping works. Just make sure that you keep track of it! Also, make your connections long enough so that the
plug
will extend outside the subwoofer box - this will be helpful for future maintenance.
This is also helpful for color. Note that the amp power + and - are two wires each.
This is my replacement harness:
The red wire is 12v + for the amp, and terminates with a bullet connector. If I had done this work first, I would have reduced my maintenance position work with the top.
My head unit also has an output wire for "Subwoofer remote" - this signal turns the sub on. If there is no sub remote signal, this can be bridged with 12v power BUT that means the amp is always on.
I find the results to be positive - I haven't had the car out with top down at speed yet so don't know how different it is. It isn't a 12 inch subwoofer that you can feel in your chest, but it definitely "rounds out" the bass sound. When it warms up later this week I will be able to evaluate better.
This is really cool,
@blaster88
- Really nice work here and definitely report back per your testing. Great write-up! I had originally thought of doing this sort of thing (I have SPP, which is 5.1) and wound up going with a Focal upgrade of the front 3 dash speakers and the 4 door speakers... and did a DIY of the rear parcel shelf (4 Kicker speakers) that was an available option for the 986/987. Sounds like you've got the "big boom" there and psyched to hear how this shakes (literally) out. Again, great job!
Day is sunnier and warmer than predicted so took it out for a test listen. Nice. It does exactly what I was trying to do - fill in the bass with the top down at speed. I figured having the sub right behind my head would help on that front.
I did have to fiddle with my settings a bit to get the best sound out of it. Head Unit settings has a "Crossover" section and the manual says:
Low Pass Filter
Selects the cut-off frequency of the subwoofer: [50Hz], [60Hz], [80Hz], [100Hz], [120Hz].
I had it set at 50Hz, changing it to 120Hz made a big difference. Makes sense with 5 1/2 inch subwoofers.
Like I said this doesn't thump your chest but it rounds out the bass. Sounds great!
My test song:
