I love music. And as such, I have always modified the sound systems in my cars. My 911 posed some pretty interesting problems and my solutions are actually easy to duplicate. So for anyone looking to spruce up their system.... Read on...
Head units are a personal preference. I prefer to look for a plain system with at least one set of line level outputs and a removable face (I do own a convertible, after all). I chose a JVC and I am very satisfied with it. It recesses quite nicely into the dash opening.
To be able to balance a system requires a Graphic EQ, but the dilemma is where to put it. For this reason I purchased the Kenwood 1/4 DIN model. This little guy fits very nicely into the open compartment in the floor console. I ran the line level output from the head unit to this little guy and put the RCA connectors in the triangular gap in the console (formed by the angle of the console and underneath the face of the EQ).
The front and rear outputs from the EQ run to a pair of amps under the passenger seat. There is a little tab on the floor toward the back and a screw near the front that I used to mount a thin board for the amps. I then spliced into the car's speaker wiring with no problems. I ran power cables directly from the battery, through the AC door in the trunk,...
...through a big rubber grommet that lead into the cabin, under the rug and to the amps.
Speakers were easy enough, stock locations front and rear. The front tweeters required a little extra work. I ran the tweeter wire from the supplied crossover along the inside edge of the door up to the top sill and flush mounted the tweeter there with some double sided tape. This places them next to the power window switches, which can be seen in the image below.
The sub woofer was the most difficult aspect of the system to figure (although it turned out not to be). I purchased a 6.5 inch bazooka with the intention of mounting it in the trunk and modifying some of the AC ducting to let the sound through to the cabin. After testing the sub without modifying the ducting I determined that it was not necessary at all.
I merely mounted a stiff board to the flimsy cowl cover, attached the speaker mounting bosses to the board,...
...cut 4 slits into the carpet for the straps, replaced the carpet,...
...and strapped the bass tube in. Being a non-powered amp I mounted a 50W alpine amp next to it on the board and ran all of the appropriate wires and cables.
This system is obviously not going to win any BOOM! competitions, nor do I want it to. In my opinion, such things are foolish. It does sound very alive and full, and it pleases the owner (me) very much. Bach sounds as good as Matchbox 20 on this system, which covers my need perfectly. For a little more punch, an 8 inch tube would probably fit in the same location.
The Graphic EQ really makes this system. It provides the life to the tweeters and gives the listener total control over the subwoofer. This is why I favor the plain head units, because I know that I will be able to better match the system to my car with an EQ than some pre-determined, factory set 'sound field'.
