DIY Audio & Video

Car Audio Projects

Installation Description (Original)

This is my attempt at installing an after-market stereo system. This car has lots of room in the trunk for amps and subs. It also has a large dash, which makes the tweeter placement tricky.

In the install in this car, I replaced all of the factory speakers and added subs. The new speakers were the same size as the original factory speakers (except for the tweeters), and were placed in the same locations. The original tweeters were 3" and were mounted to a baffle under the dash. The new dome tweeters I had were too small, so they just sat in the hole directly under the baffle for the old speaker.

The new 5 1/4" mids were slightly deeper than the factory ones, and were too deep for the doors. Luckily, the mids were recessed 1" in the door, with a grill that was flush with the door. This recessed area was oval shaped, and much bigger than the speaker. I made a 3/4 baffle under the grill, and mounted the mid to that. The grill still fit over the speaker, covering up the make-shift baffle.

The 6x9's fit perfectly in the stock locations, and did not require any extra work.

For the subs, I built a 3 chamber bandpass box. I wanted to make the best possible use of the trunk space I had, making the box as wide and tall as possible in the trunk. I didn't want the box to stick out beyond the rear deck, so it wouldn't get wet in the rain. I also wanted the ports to fire upward through holes in the rear deck. Unfortunately, the box I wanted could not fit through the trunk opening, so it was necessary to assemble the box inside the trunk. Yes, all gluing, screwing, caulking and carpeting was done inside the trunk. I would not recommend this to anyone, and I will never attempt this again. Still, the box turned out well. It sounded great and looked good. It also left a lot of room in the trunk, even though it was over 5 ft³.

Trunk without and with the bandpass sub.

Since there is only a donut for a spare tire, there is a lot of room in the spare tire well. This is where I put the amps. I mounted the amps to a carpeted piece of 1/4" aspen plywood which sat directly on the spare tire. A piece of 1/4" plexiglass rested over the amps where the original spare tire cover was located. Two fans were mounted below 3" holes in the plexiglass for ventilation. With the Rockford Fosgate amps, all wiring is hidden under the end caps and is run through and behind the mounting board.

Bandpass Subs and Amplifiers in Trunk

Installation Description (Rework)

When I upgraded my system, I was mostly interested in a better sound stage. I wanted more bass up front and less music coming from the back. I also wanted to position my speakers better to raise the sound stage from the floor. To do this I replaced the front speakers and subs and got rid of the rear 6x9 speakers altogether. I upgraded to 6 1/2" mids in the doors and better quality subs. I decided to use the 400x4 amp entirely for subs, instead of just 2 of the 4 channels, so that I could get more bass. I also wanted tighter bass so I switched to a sealed box.

The tweeters were again mounted in the factory location. This time I made a 4x4" baffle that the tweeters were mounted to. I mounted this above the original 3" tweeter location under the dash. This put them closer to the dash which hides the speaker. This is necessary, since the hole in the dash is only 3" wide.

The 6 1/2" mids were again mounted in the factory door location which was an indented 6x9" oval intended for a 5 1/4" speaker. The new mids were too deep and large for the factory mount so I mounted the new mids to a 3/4" MDF oval baffle. This raised the speakers enough so that they would not interfere with the windows. It also moved the speakers out beyond the indentation, because they were too wide. I covered the baffle with duck cloth because it is thin and durable.

The subs fire into the passenger cabin through the rear seat arm rest hole from the trunk. This car did not come with a pass through from the rear seats to the trunk, so I had to create it. Some cutting and re-carpeting of the trunk had to be done to create this hole. Two holes had to be cut: one in the rear seat in the arm rest and one in the back of the trunk. I also carpeted behind the rear seat to cover up the sheet metal between the rear seat and the trunk. This carpet was sewn to the carpet on the inside of the trunk. Looking into the trunk from the back seat, all you see is carpet. Looking into the back seat from the trunk you can see the foam in the back seat. I didn't cover this, since normally the sub will block this view.

Sealed Subs and Amplifiers in Trunk

The JL subs are 6ohm DVC. I ran both voice coils in parallel for a 3 ohm load, and used 2 channels bridged from the 4 channel RF 400x4 for each sub. Running the amp 3 ohms bridged is lower than spec for the amp, and is the reason for the extra fans. I added 3 fans to blow directly across the cooling fins of the amps, and kept the 2 fans in the plexi to circulate air in the amp compartment.

As for the rest of the trunk, there is a fuse/distribution box on the left side. The crossovers for the front speakers are on the right. The capacitor for the sub amp is hidden under the board that the amps are mounted to. This way, the distance from the cap to the sub amp can be kept very short.

Component List

• Signal
  • Alpine CDE-7831 Head Unit
  • Kenwood KGC-6042A 11 Band EQ
• Amplifiers
  • Rockford Fosgate Punch 4080DSM
    • 40Wx4
    • Bridged 2 channel at 4 ohms for components.
  • Rockford Fosgate Punch 400X4
    • 50Wx4
    • Bridged 2 channel at 3 ohms for subs
• Speakers (Updated)
  • A/D/S AL6 6 1/2 mid + 1" tweeter component set
    • Placed in stock position in dash and doors
  • 2 JL 12W6
    • DVC in parallel for 3 ohm load
    • In sealed box in trunk
• Speakers (Original)
  • 2 Kicker ND-22 25mm Titanium Tweeters
    • Placed in stock position in dash
  • 2 Rockford Fosgate Punch SP54P 5 1/4 Mids
    • Placed in stock position in front doors
  • 2 Clarion SE-3903 6x9s
    • Placed in stock position in rear deck
  • 2 Rockford Fosgate Punch 1812 8 ohm (parallel 4ohm) 12" Sub Woofers
    • In fourth order three chamber single reflex bandpass box in trunk
• Wire - Phoenix Gold / Monster Cable / Rockford Fosgate / Audio Quest
  • 4g power & ground
  • 12g speaker wire
  • 15' interconnects

Car Wiring Diagram