Description:
I already had one 2 channel Infinity 7521A from my Sub Box II Project, so I wanted to reuse it in this complete overhaul. It puts out close to 100w RMS per channel, so it would work well driving a pair of components. To complete the system I bought another 7521A to power the second pair and a 1210A mono sub amp to power the subs. The 1210A puts out 1300W at 2 ohms, which will be more than enough for my two 10″s. The difficult part would be fitting these three amps at the back of the cabin wall.
Here you can see the basic layout I would use for the amps and crossovers.
Fabrication:
The amp rack started out as a large piece of 3/4″ MDF. I took measurements of rear cab to figure out how much room I had to play with. I then layed out all the components on the board and traced them and drilled my pilot holes for the mounts. In order to get the rack to sit flush with the rear wall I would have to notch the back of it so that the bolt heads on the cab would counter-sink into the board. I also added some odd thickness strips of MDF to the rear of the board. Two small blocks of MDF were added to the right and left hand side of the rear of the board for further support. After test fitting the board I added another piece of MDF to the lower left hand corner (while looking to the rear of the truck) to mount the 3-way fuse distribution block. This added piece follows the contours of the cabin floor. The last step before installation was to carpet the rack. I used black automotive carpet that I found at Wal-Mart, and used 3M spray adhesive to secure it as well as industrial staples along the back side.
Here you can see the back of the amp rack with the countersunk holes for the cab bolt heads and also the strips of MDF added so that there would be clearance behind the board to run the wires and the board would sit perpendicular to the cab floor.
This shows how the notches allow the board to mount flush to rear wall. Note the piece of masking tape, this is how I kept the board centered. You can also see the outline of the crossover and amp.
Here’s the rack just prior to being carpeted. On the left side you’ll see the additional piece of MDF I installed to mount the distibution block. You can also see how I drilled the holes for the RCAs, which allowed me to run them from underneath the amps.
This is after being carpeted and the carpet over the wire holes removed.
Here’s the final product with the seats still removed. The rear wall cover had to be cut out along the edge of the amp rack so that the rack would mount flat against the rear wall. Small black plastic caps were used to cover the 5 mounting screws. I also used scrap pieces of the rear wall carpet to cover up all the b-quiet mat that was showing through the various openings in the rear cover.[/color]
Foreword:
I originally purchased the Matrix line driver with the intent to use it in conjunction with the OEM RF HU. It was needed to overcome the RF‘s horribly low output voltage. When I decided to go with an aftermarket HU, I figured it couldn’t hurt to have the benefits of maximum voltage and a subsonic filter.
Description:
The Matrix is made by AudioControl, and basically is a line drive. It boosts the signal coming from an RCA cable up to 13V (peak.) It has 6 inputs/outputs, that’s front/rear/sub. Using it with the already decent output from the JVC HU allows me to run the amps at zero gain. The idea is to reduce electronic noise in the system.
Specs:
» Six Channels of Input and Output
» 24 dB of Signal Gain – 13 Volts Peak Output
» 12 dB of Signal Attenuation
» PFM Subsonic Filter
» Output Level Controls
» Balanced Differential Inputs
» Linkable Inputs – 2 Input Channels to 6 Output Channels
» Low Impedance Outputs
» Voltage Indicator LEDs
Installation:
Line drivers work best when placed as close to the source audio (head unit) as possible. So now for the challenging part. At first I thought I could mount it within the glove box. After actually getting it in the glove box, I soon realized that it wouldn’t fit once the RCA cables were installed. I even tried some right angle adapters. The end result was a cut up glove box. Luckily for me I was able to get a new on off of another member for a good price. The next try was to mount it up under the glove box above the passenger foot well. After a little work, I got it in there. The Matrix requires 12V power, a power on signal, and a ground wire. I ran a new 14ga power wire through the hood release grommet, under the dash, and to the Matrix’s location. The turn on signal was tapped off of the HU‘s amp on signal, and I grounded it to a dash bracket screw.
This is the wiring prior to installation of the Matrix. The RCA cables were wrapped in split loom to protect them from cuts on the sharp dash frame (not shown.) The wire coming from the HU is one 1m 4 channel, and one 1m 2 channel. Again, HVAC aluminum tape was used to secure wires to flat spots where zip ties could be used.
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