Hi all, I’m new here but wanted to start contributing to the cause and help out any fellow Porschephiles who might be trying to do what I just finished doing on my
2012 Cayman S
. Apologies in advance, I thought that I had taken more photos throughout the process to document it, but alas I’ve only got a few to include here.
My
Cayman
came with
PCM 3.0
and the
Bose system
, and I wanted to have something a bit more modern that would be
Android Auto
compatible since I’m used to using it in my other vehicles. I didn’t want to perform the retrofit on the stock unit, so I opted to buy a
Kenwood DMX8709S
head unit, a
JBL DSP4086
amp and some
Rockford Fosgate R165-S
component speakers from Crutchfield. I’m still using the stock midrange, center and rear channel speakers and for now, they seem fine.
The Crutchfield instructions and tech support were helpful, but I really found the detailed guide at
CAI-Store.com
to be the most useful guide during my install. Looking at their photo of their subwoofer retention harness was enough to let me reverse-engineer it and make my own since I wanted to keep the Bose subwoofer. Additionally, their guide for finding the accessory, illumination and parking brake wiring was something that wasn’t included in the Crutchfield guide.
Here’s my first photo of the back of the unit as I first slid it out of the console. Note the black connector on the left (antenna) and the small blue connector to the right of it (GPS), as those are the two I reused when connecting the new Kenwood unit. Rather than mount the new GPS antenna that came with the Kenwood unit somewhere, I found an adapter cable that would let me connect the stock blue GPS lead to the Kenwood. If you want to do the same, you’ll need a
Fakra Z Male plug to GT5 male plug adapter
that costs about $12 on Amazon.
The battery (red) and ground lead (brown) were easy enough to find from the bundle of wires that come out of the large harness plug at the back of the unit. I used wire taps that included female spade connections for those and then looked for the accessory and illumination wires which (per the CAI instructions) were found on the connector for the HVAC controls. In the photo below, they are the red and yellow taps near the top of the image (yellow for the accessory orange wire and red for the grey/red illumination wire). The lower connector is for the Bose subwoofer. I have installed insulated connections on it for the 12v remote turn-on from the receiver (white/yellow wire), positive speaker input (orange wire) and negative speaker input (orange/brown wire). Behind the sub connector are 4 grey wires that are for the low-level (RCA) amplifier connections and the blue wire running down to the right is the 12v turn-on lead for the amp. You can see the 8ga amp power wire just below the footwell vent duct, it’s tucked up under the carpet along the center tunnel before dropping down below the passenger seat.
--
To recreate the harness for the Bose sub, I picked up an inexpensive RCA cable from Amazon and cut it to 18” length. Since the amp is a single (mono) unit, I stripped the insulation back, exposed the positive and negative wires on both sides and then spliced the two positive wires and two negative wires together. Then I took an additional piece of 18ga wire for the turn-on signal and bundled them all together with some braided nylon sheathing to keep things neat.
Now it was time to work on figuring out the AMP wiring. There are a ton of wires coming out of the Bose amp, and I ended up using a 9V battery and touching each of the terminals to the pairs of wires to determine which speaker they corresponded with. Each time I heard the little 'pop' I noted which speaker made the noise. Here’s what they were in my car:
Here’s the amp wiring before I cut the connector off:
Here’s the amp location with much of the pre-out wiring, power wiring and insulated connectors finished. The arrow in the image is where the rear of the Bose amp was bolted down and turned out to be an excellent ground after testing the resistance between it and the negative battery cable. I’ve installed a sheet of sound deadening to the floor under the amp location to provide some cushioning.
Here’s a photo where I’m still working on the amp positioning. You can see it’s rather crowded in there with all the wires. The amp is an 8-channel unit with 40 watts RMS per channel at 4 ohms and has six RCA inputs. I’m only using 4 of them since the two subwoofer pre-outs on the head unit are going straight to the Bose sub. The amp dimensions are very close to the stock Bose amplifier, so it clears everything under the seat with ease. I ended up using some adhesive backed, high-strength velcro to attach the amp to the sound deadening and it felt really solid. I don't think it's going to come loose without manually trying to pry it out.
With the amp wiring sorted out, now it was time to get the new speakers installed. I started with the tweeters since they’re easy to access on top of the dash. Using a plastic trim tool made it easy to remove the covers and get to the stock Bose tweeters. Here’s a couple of photos of the left tweeter installed and the foam I trimmed out from the cover to increase clearance.
The woofer install required a bit more strategy though, as I wasn’t impressed with the plastic pieces that were supposed to serve as the mounting holes from the Crutchfield kit. Their diameter was just barely larger than the hole in the door and I also didn’t like the idea of drilling more holes into the door in order to use the kit pieces. Instead, I opted to modify the stock plastic woofer housings that the Bose speakers attached to since they had a much more secure mounting setup and better seal against the door. Before that though, I made sure to apply more sound deadening to the door to help improve the speakers’ sound and lower the road noise.
I had some leftover ½” Baltic birch plywood from a previous project, so I cut some circles of it that would fit into the stock plastic speaker mounts. Cutting a smaller hole into the wood was easy enough to mount the new woofers, and cutting the plastic fins from the back of the mounts to provide clearance was easy. Here’s the first woofer installed into the stock plastic housing. I used some 1/16" foam tape behind the woofer to seal it against the wood. The foam seal on the stock plastic adapter was already in good shape, so I just reused it.
Here it is mounted into the door. Learn from my mistake! Note that the positive wire coming from the amplifier (white/red) is coming into the bottom of the connector and coming out as a BLACK wire to the stock speaker. I first connected the black wire to the negative lead on the speaker and caught my mistake afterward, having to redo my connections.
After repeating the process on the other side, it was time to start buttoning things up. After bundling up the mess of wires behind the head unit and using some cloth tape to wrap up any of the plastic connectors from the stock unit so they don’t start rattling against anything, I finally got the Kenwood head unit into the dash. You can see where I opted to mount the microphone on the small trim piece to the left of the center console. I had to do some minor filing to the back side of that trim piece to have enough clearance for the microphone mount, but it was easy enough.
The Kenwood unit has a ton of sound adjustments - I won’t go into all of them here as everyone has their own sound preferences, but I think that most people will be able to tune things to their preference. In my opinion, the slickest part of this whole install is the JBL amplifier since it can connect to a laptop via USB and you can set up crossovers for each of the channels coming out of the amp to the speakers.
This is what the software looks like when running (I borrowed this image since I didn’t take one of my own):
On my setup, since the midrange and tweeters share the same output from the amp, I have those crossed over with a high-pass at 600hz. The door woofers have bandpass crossover from 80-600hz and the center channel and rear full range speakers are set up for bandpass from 500-16000hz. Since the subwoofer gets its output from the head unit, it’s crossed over there. I really like that you can adjust the volume/gain from the software and boost or cut individual channels to find the right balance. You can even set time delay here (or on the head unit) if that’s your preference.
I hope that this guide is helpful for folks that are looking to perform a DIY replacement for their Bose system with PCM 3.0, as I hadn’t found a really comprehensive walkthrough in my searches.
Cheers!
