Page 7

The Audio Video System

This stealth subwoofer project is complete! It was designed to fit a massive speaker into the smallest space possible. Unlike most subwoofers that have been put 740s and 750s, it takes up little trunk space. The cabinet was custom made to maximize the interior volume, while fitting into a portion of the trunk that would not normally be used. The box is small enough that I can still get the spare tire in and out without having to move anything

A 2000 watt RMS, class D power amp provides all of the power that could possibly be needed to power the JL Audio 15" dual voice coil subwoofer.

An MP3 player with a 40 gig hard drive is included. It can hold nearly 700 hours of CD quality music. A wired remote is being added to the dash. I'm still in the process of modifying it to have amber backlighting.

A 120 volt, 300 watt (600 peak) power inverter is included so that household electrical equipment can be used.

I�ve also added a TV module and mirrored reverse camera.

It all started with this rather crude diagram. I grabbed a piece of cardboard and cut it to fit the contours of the trunk where the ski bag goes. I cut out a separate piece of cardboard (not shown) to exactly fit over the outside dimensions of the speaker that I had selected, a JL Audio 15-W3. It took lots of trial fitting to get it to match the speaker dimensions exactly. I then transferred these dimensions to the cardboard representing the space available in the trunk. The speaker is massive and as you can see, it takes up the majority of the cross section of the box.

The sub box under construction, the shape is designed to fit exactly into the available trunk dimensions while taking up a minimal amount of space. The full width and height of the trunk space is utilized.

Note the braces to strengthen the back to prevent vibrations. They are securely glued and screwed to the back panel.

Note the minimal depth of the cabinet, only 14 inches deep at the bottom, which is exactly what was required to fit the beefy magnet structure of the JL Audio 15-W3. The back of the speaker fits right in between the back braces and leaves about 1/4" of clearance from the back wall.

Here is the speaker box with covered with genuine BMW trunk carpeting for an exact color and texture match. Not shown is a 3/4" thick heavy duty form rubber strip across the front so that the speaker cabinet can fit snugly against the seat back without any vibration.

Here is the extra section of trunk carpeting and the speaker cabinet, both with an application of contact cement. The trunk carpet has holes in the middle for tie downs, so positioning was critical to make sure that the holes fell into the scrap area.

Here is the trunk with the ski bag and back panel removed to gain a bit of additional clearance.

Here is the empty speaker cabinet fitted into the trunk. As you can see, the hole for the speaker matches up perfectly with the hole for the ski bag.

Here is the speaker cabinet with the back on for a trial fit.

Here is the completed speaker cabinet with the back and the carpeting in place.

Here you can see the shelf for the electronic equipment installed. It is in the normal operating position, which holds the speaker cabinet in place.

When the two latches under the shelf are released, the cabinet swings down for easy access.

The shelf continues to arc upwards until it is level with the trunk floor. Underneath there are two folding legs that hold the shelf securely in a level position. In this photo, the lighting makes it difficult to make out some of the equipment.

Here is a close up of the equipment installed on the shelf. From left to right: 12 volt power outlet, MP3 player, 120 volt inverter, fuses, power amp.

Here is a close up of the speaker cabinet in the installed position. The two latches on the side are in the down position. The wooden versions are somewhat temporary. I will eventually replace them with another material, possibly aluminum or Teflon.

Here is one of the two 1 farad capacitors that helps insure that the electronic equipment has lots of stable reserve power under any conditions. Note that the wires have not yet been installed under the side trim panels.

Here is the second 1 farad capacitor. As you can see, they tuck into the small space at each side of the speaker cabinet. Note that the black plastic attachment points for the cargo netting are still fully usable and the cargo net still fits in place.

This is the shelf for the electronic equipment while it was under construction. It was cut specifically in the space under the deck lid, which required cutouts in several areas to match with the contours with the car body. The open area in the center allows easy access to the third brake light for changing the bulb and lets the built in trunk illumination function as it was designed.

Here is the electronic shelf hanging down in a vertical position.

Here is the shelf with the legs extended so that it is positioned horizontally.

Here is a similar shot with a bit more angle.

In this shot from the right side, the 2000 watt Boss Audio Class D amplifier can easily be seen.

Here is a shot of the equipment shelf in the vertical position, this time from the left side of the car.

Another shot with the shelf in the horizontal position. Note that all of the wiring is easily accessible with the shelf open, yet is located in the most protected position with the shelf secured.

This shot from the left side shows the 12 volt power converter, MP3 player, analog to digital converter and power supply, line level converter, switching relay, noise filter, 120 volt inverter, power distribution and fuse blocks, with the amplifier on the far side.

With the rear seat armrest in the closed position, there is no clue to the power that is hidden behind.

With the armrest in the open position, the JBL 15" dual voice coil 15-W3 subwoofer is positioned to deliver enough bass to literally create wind inside the car.

One of the design goals was to have a fully usable trunk.

As you can see, the spare tire is completely accessible without having to disconnect or move any of the equipment. Note the optional �bunt cake pan� insert in the center of the wheel. It allows you to use the area for storage without getting anything dirty. Small items can�t fall through holes in the wheels either.

This shot shows how much of the trunk space is still available.

Adding the video module is fairly simple. It takes some minor modifications to the wiring harness. While I was at it, I ran a bunch of spare cables for future expansion. They are bundled in front of the CD changer and television module.

On the other hand, installing the antennae cables in a large undertaking. All of the rear seats, C pillar trim and rear package shelf must be taken apart. It is much easier to actually leave them in the car, that way the seat belts and wiring does not have to be disconnected.

Here is the rear window area with the package shelf and sun shade removed. The large silver boxes mounted to the C pillar are the amplifiers for the radio. There is one on each side. The small silver box below is the amplifier for the TV receiver. There is one on each side as well.

With the seat bolster removed, you can see the extra cabling that I installed while everything was torn apart.

The built in LCD screen in the dash has many purposes.

The onboard computer can display the radio settings, a pre-set speed warning, distance to destination, range based on fuel in the tank and the current gas mileage, arrival time at destination, stopwatch, to gas mileage counters and the average speed.

The built in navigation system can pinpoint the location of the vehicle within 30� and has a built in database for many different services including gas stations, restaurants, hotels, attractions, etc.

The built in phone is voice activated, or can be operated from the built in screen and steering wheel controls.

Country, language and measurement preferences, as well as various settings can be easily changed at will.

Because I added the TV module, television can be viewed on the built in screen.

The Digital Signal Processing, including equalization, reverb and room settings can be adjusted as necessary.

There are two built in timers that can automatically turn on the car�s ventilation system to help cool off the cabin before your anticipated arrival.

In case of emergency, the system can automatically report the vehicle�s exact location and request emergency assistance.

With the installation of the TV module and mirrored reverse camera, a wide angle camera automatically displays the view from the bumper any time that the car is shifted into reverse.

Here is the installation of the reverse camera in progress. It is set into the bumper to match the park distance controls. An extra hole was drilled into the bumper to accommodate the camera.

This is the back of the reverse camera that fits into the newly added hole.

Here is a close up of the park distance control sensors and the reverse camera. The camera was painted to match the park distance control sensors as closely as possible.

From a distance, the reverse camera blends in very well with the park distance control sensors.

The center console houses a CPT-6000 analog phone, which will hopefully be upgraded to a digital CPT-7000 or CPT-8000 at some point in the future.

I�ve added an aftermarket cup holder from http://www.cup-holders.com

Please browse to the following pages:

1 Introduction
2 In the Beginning
3 From the Front
4 From the Side
5 From the Rear
6 The Interior
7 The Audio Video System
8 Both of My 750iLs
9 May Puget Sound Meet
10 June Puget Sound Meet
11 July Puget Sound Meet
12 Engine and Drivetrain
13 BMW Club Concours d'Elegance
14 BMW Advanced Driver Training
15 BassLink Install
16 Oil Change and Oil Pump Bolt Check
17 Quad Rear Brake Lights
18 Phone Install
19 Jets
20 Strong Strut
21 Eisenmann Exhaust
22 Sway Bar Upgrade