In keeping with our goal of achieving high-fidelity sound without springing for the “high end” (JL Audio ZR series, Polk Audio Signature Reference, the crazy-good Focal Utopia Be, etc) we chose to install a set of the brand-new JL Audio C2 650 components in the Yukon’s front doors.  For now, we’ll be powering them with the Alpine CDA-9887’s 18 watts RMS per channel.  

Scoping out the mounting locations
Matt and I started on the driver’s side and quickly discovered that installing the new speaker system would require a minimal amount of customization. Pulling off the door panel and looking at the factory speakers, we realized that the tweeter was part and parcel with its mount. Removing it just left a big hole – far too big to accommodate the flush-mount adaptor that comes with the C2s. The factory woofer was snapped in place via mounting tabs at the top and bottom of the speaker. This mounting configuration would, of course, hold true for the passenger side door, so we now had a better idea of the scope of this part of the project.

Mounting the drivers
We marked the woofers’ mounting hole locations in the door frames and drilled through with an 1/8” drill bit. We would also be placing Boom Mat acoustic baffles in the opening, but they don't need mounting holes -- their foam construction allows for easy drilling anywhere on the baffle lip. The cavity behind the door frame was spacious – clearly enough to hold the woofer and the crossover network. The large opening for the factory tweeter/bracket, on the other hand, needed to be adapted down for the C2 dome.  Before fabricating something, though, we worked with the factory bracket to make sure there wasn’t some sort of way to keep using it – either by cutting out the built-in tweeter and replacing it with the new one, or by surface mounting (2-side tape? Velcro™?) the tweeter on top of the factory tweeter, as it looked like it would still fit under the door grille easily. I thought the surface mounting idea was pretty clever until Matt astutely pointed out that there would be no easy way to route the wires back behind the door panel. Drilling into the plastic factory mount probably would not have been a successful experiment. Likewise, cutting out the plastic factory tweeter would have likely resulted in a mess. So fabricating a mounting bracket was beginning to look like the best solution. But how? Clearly, whatever material we used, we’d have to affix it to the door panel plastic somehow. Hmm. I looked around our installation bay, my eye catching the open box of Dynamat next to the truck. Eureka, the solution was apparent in my mind’s eye. Stretch a piece of it across the back of the opening, cut an “x” into it, push in the C2 tweeter’s surface mount cup, reinforce with more Dynamat if necessary, and violà: a secure mount.

Placing the crossover
Rather than simply tossing the crossover network into the bottom of the door cavity, we were inspired by our Dynamat tweeter mounting trick to do the essentially the same thing here. In this case it would be a simple matter of cutting into the Dynamat that we had already installed into the door many weeks previously, placing the crossover and reinforcing with some additional Dynamat. This would allow for a solid, easily accessible mount and minimize the lengths of speaker wire we’d need to add to the factory wiring.

Connecting and routing the wires
The Crutchfield-provided speaker wiring harness was helpful in giving us a snap-in connection to the Yukon’s speaker wiring system, but we were on our own making the rest of the connections. I cut off the harnesses’ speaker-side ends and crimp/soldered male spade connectors in their place. “Crimp/soldered,” you ask? Well, yeah. I don’t completely trust a crimp connection that’s going to live in an in-motion, difficult-to-access location; yet I certainly wasn’t about to solder connections directly into a crossover device or onto speaker terminals that I might want to remove in the future. So I crimped on the spade ends, but reinforced those connections with a little solder inside the metal sleeves that house the bare wire.  

The C2s don’t come with any speaker wire, so I grabbed some from our installation bay and cut four pieces just long enough to reach the speaker locations without being taut or bunching up in the door cavities. Again, male spades on the crossover side, but females for the woofers and males for the tweeters. The tweeters had short lengths of wire already soldered onto contact points – rather than actual wire terminals – on the side of their housings. Unfortunately, one of those contacts had come loose in shipping, and we were faced with having to reconnect a wire with no actual terminal to use. We really didn’t want to take the time to send the tweeter back to JL Audio for an exchange, so Matt decided to join me at the soldering bench and solve the problem by soldering the wire directly back on to the lump of JL factory solder. The connection held.

Pet peeve: whoever’s making speaker wire without marking or color coding the strands so one can easily discern positive from negative at each end, this camper was not happy. ; )

The sound
Upon completing the driver’s side installation, we let the stereo play for a little while as we cleaned up the installation bay (we saved the passenger side door for another day). We had both front doors open and the difference in sound quality when we walked around the back of the truck was astounding. It was as if there were two different stereos playing. Walking left to right revealed a diminishing in presence, detail and tone. We knew we were definitely on the way to a major sonic upgrade. In the next couple of days, I will post a video a video demo to give you a sense of the overall improvement once we finished the passenger side.

Photo Gallery (Taken with Canon's hot EOS Digital Rebel XSi SLR camera)

Passenger side door woofer opening. Note our wiring harness (connected to factory wiring plug) with new spade ends, ready for connection to the crossover:

Matt (well, arms & torso, anyway) with baffle and JL Audio C2 650 woofer:

  Matt  drilling holes into door frame after using the speaker to mark hole positions:

Back of door panel view of tweeter mounting hole covered by a piece of Dynamat:

C2 650 tweeter with equipped wire connected via spade connectors to extra speaker wire (soon to be attached to the crossover):

Front of door panel view of tweeter mounted into the Dynamat strip:

The spot directly behind the dangling black connector is where we would cut through the Dynamat to mount the crossover:

Crossover mounted into Dynamat below the woofer:

Securing the woofer in place:

Closeup of the mounting area: