he goal: to recreate concert-quality sound in one of the worst acoustic environments (a car's interior, complete with road noise), while not giving up interior room or usable trunk space, greatly modifying the car, or interfering with use or enjoyment of the car for its intended purpose (driving, remember?).
I started with a clean slate (and the empty shell of a car) so I was free to do literally anything I could think of with this installation. So, after eliminating all those thoughts I couldn't afford, I did what was left. I decided not to be prejudiced against nor favorable towards any particular brand of equipment without practical reasons. I will try to explain why each particular piece of equipment was chosen, and how it was installed for peak performance, and to take best advantage of available space. For what it's worth, the end result was, and is awesome!
Schematic Diagram The schematic diagram I used to plan the installaton of the stereo, alarm and cellphone systems, 59k.
I might add, I am not a professional installer, nor an electrical engineer. This entire project was to be done by me, with my tools, on my limited budget. Somehow, I got it done! Let's see if I can remember how:
OK, here we go! Everything starts with the head unit, in this case a Denon DCT-950R AM/FM Receiver/CD Player. Denon is by far my favorite brand of head unit, not only for their superior specs and excellent sound quality but also their ergonomics - when was the last time you saw a volume knob? This unit has a frequency response of 5-20khz +/- 1.0db. Yes, that's +/- 1.0db, not 3.0db like others' are rated. For reference, humans can only hear down to about 20hz, below that is only felt. Dynamic Range and Signal-to-Noise ratio are both 96db. 2.2v preamp output voltage helps keep the noise out. Some of this may have gone over your head but bear with me. It all means this thing is incredibly clean. The radio's lights match the car's dash lights (green) and the infra-red remote control stows in the armrest. Hooked up in the trunk is a Denon DCH-520 10-disc CD changer, controlled by the head unit. Music signals travel through Monster Cable XLN interconnects (very expensive shielded cables) down the left side of the console towards the trunk. Why are these cables important? Because you're sending a relatively low voltage signal (preamp outputs bypass the amplifier in the head unit) through a long wire. That's basically the definition of an antenna. Without shielding that length of wire would pick up lots of electrical noise along its path from the car's systems and you'd get pops, hiss and whines along with the music. We can't have that, can we? Note the tweeter in the passenger kick panel (above and to the right of the cellphone).
Before we get to the trunk electronics, let's finish up with everything inside the car. The most critical thing to how the system images is the placement and aim of the front speakers. In a competition system, you are trying to recreate a live performance, so the sound must come from in front of you, with little or none from behind. Those with stock stereos in their cars are probably used to the opposite effect, because most cars have larger rear speakers than front and you get better bass that way. Not very realistic, though. The sound must also have accurate imaging. In this car you can listen to a song, and hear the locations of the main vocalist, the backup vocalists, and even the placement of each orchestral section onstage. What you can't hear is where the speakers are. To accomplish this required several things: First, the distance from your ears to the left and right speakers must be as close to the same as possible. Stock speakers are generally in the doors, but this means one is very close and the other is quite far away, not to mention they fire into your legs. Placing the speakers in the kick panels is about as close to equal as you can get, try it and see. Second, I placed the bass driver and tweeter as close together as possible. This allows all frequencies to hit your ears at the same time. Since your brain recognizes micro-second time differences, the popular practice of putting the tweeter up high in the dash while the bass driver is low in the door ruins imaging. Your brain hears the upper part of a singers voice from one place and the lower from another. Finally, I placed the driver's side tweeter aimed at the passenger's head and the passenger's tweeter aimed at the driver's head. This compensates some for the still-unequal distances because you tend to hear the speaker more when you're directly in-line with it. Ideally, the bass driver would be aimed this way too but I didn't want to sacrifice footroom, and bass frequencies are much less directional (harder to tell where they're coming from) than the highs from the tweeters. This location also allowed a "clear shot" from the speakers to both front-seat passengers without being blocked by the console or their legs. Back to the picture, this shows the left kick panel under construction. 1/4" plywood closed out the area and was then sealed (not shown) to be as airtight as possible.
The more airtight you can get the enclosure, the better bass response you'll get. This is because to create bass you must move air, and leaks from the back of the speaker cancel out the sound waves from the front. Don't believe me? Try to get bass out of those naked 6x9's laying loose in your rear window! After sealing, the stock carpet panel was attached, then the speakers were installed and aimed. From outside the car, all you can see is the stock speaker grill in the door, which no longer has a speaker at all. The kick panels hold an MB Quart 215.02CX component set with a 5-1/4" woofer and a 3/4" tweeter. Quart's titanium-dome tweeters are the silkiest sounding I have ever heard, and the woofers put out better, tighter bass than many much-larger drivers I've heard.
In the rear doors, I installed MB Quart QM 100.21 KN-R 2-way coaxial 4" drivers (whew!). Since these only provide a little "rear fill" to simulate sound bouncing off the back wall of an auditorium during a concert, they can be smaller than the front speakers. They're also turned way, way down so you don't notice them during normal listening, yet they can be turned up when I have passengers in the back seat. Ideally you would add a time-delay unit on these but this is a budget system, remember? The stock rear door locations worked perfectly, but did require a custom spacer to keep the tweeter from hitting the grill. Everything was sealed up as airtight as possible just like the fronts.
I wanted to keep the system as stock-looking ("stealthy") as possible for those "prying eyes," so I kept the stock grills on the doors, merely adding a discreet MBQuart logo. You can't see it here, but over the subwoofers (we'll get to them) in the rear shelf below the backlight (rear window, remember), I made a new package shelf from 1/8" plywood, cut out circles over the subs, and covered the whole thing in black speaker grill cloth. This allows all the sound to come through while completely hiding the speakers from outside the car. It just looks like the stock shelf from outside.
Man, this is ugly! This is the left rear seat, looking from the right side, or it would be if the rear seat was here (it isn't). These are some of the wires for this whole stereo thingy. I ran the power (+12v dc) wiring down the right side of the car, and the preamp cables down the left. Some say this helps keep noise out while others say it doesn't matter, hey better safe than noisy, right? The blue wires in the photo are the preamp cables from the radio going to the amp (4 total, 1 for each channel: FL,FR,RL & RR). It looks funny, but they run partially through the unibody structure (right side of the photo) of the car. Grommets are used to ensure the wires don't chafe against the metal and short out. To get into the trunk you must penetrate the rear firewall (left side of photo), this is done with another grommet and then silicone-sealed airtight.
Why a rear firewall, you ask? Good question - most cars don't have one, there's little or nothing between the rear seatback and the trunk. However, the Jag's trunk contains 2 fuel tanks, the fuel pump and filter, and lots of fuel line, so the area is completely sealed from the passenger compartment. Remember this fact because it comes into play later with the subwoofers. Photo: So far, this is actually a stock wiring route. This picture shows the stock wire shields replaced, they barely fit over all the added wire. The green and pink wires are really multiple wires inside colored sleeves running from the amp in the trunk up to the front and rear speakers. They route under the threshold plates. It's important to use quality, heavy wire when running it this far. The flimsy wire that comes with most speakers will actually lose a significant portion of your amp's power to heat during use, and you want to hear all those watts you paid for, right?
On the other side, we have the power wiring. Yes, you see the same pink and green wire bundles going to the right-side speakers, but we also have all the wiring for the CD changer, power antenna, cellphone, alarm sensor for the trunklid, etc. The giant red wire is a 1-gauge welding cable that connects the front battery to the rear battery. The whole mess got covered with plastic shields just like the other side. Every hole in metal gets a grommet and those in the firewall get silicone-sealed as well. None of this is visible with the seat in place. Oh, why a rear battery? Because, although the front battery would work just fine in everyday use, sometimes I like to park and "crank it" for a while. Since the entire stereo system runs off the rear battery, even if I were to drain it completely I would still have the front battery to start the car with.
This is the front battery under the hood in the stock location. In front of it there is a Stinger 200 Amp Fuse Holder. Power runs from the positive terminal, through this fuse, to the relay directly in front of that. That giant red wire you saw in the last picture connects to the other side of the relay. This relay is activated by the ignition key, so that when the key is on, both batteries are connected and both are charged by the alternator. When the key is off, the batteries are disconnected, and playing the stereo cannot drain the front battery. There's a backup switch in the center console to override this, i.e. if I were to leave my lights on the the front battery went dead, I could switch the relay on and start the car from the rear battery - go ahead, ask me how I know. After the photo was taken, boots were installed over the terminals to prevent anything from touching them and shorting out. A note on competition: so far, everything is pretty kosher with IASCA regulations (see links page). Things like all the gold-plated terminals and plexiglass fuseholders are mainly for competition points, but that was not a primary consideration. Competition provides lots of points for things like plexiglass covers, motorized amp racks, neon-lit fishtanks, etc., and I just didn't want those things in my car. Remember the "goals" at the top of this page - no unnecessary use of space, sacrifice of utility or depletion of my finances! While I enjoy competing for sound quality, I'm just not into it to that extent, so bear that in mind if you're comparing this to your present or future system. Onwards...
This is the trunk, in stock configuration. On the left and right you can see the wiring coming back through the firewall from the previous photos. In the center are the sunroof motor and ignition box, and that large silver box on the right is the fuel injection computer. The black stuff is sound deadening material I added. Down in the spare tire well, the silver can on the right is the fuel filter, and behind it is the fuel pump. Problem: how to add lots of electronics to an area full of fuel vapor without becoming an accidental human torch? The bigger problem: how to fit a battery, a capacitor, an amplifier and equalizer, two subwoofers with enclosure, four crossovers, a cellphone brain and all associated wiring and fuses without sacrificing trunk space?
Let's cover several things at once, it will make sense in the end (I hope). Biggest decision: subwoofer enclosure. My choices were: a sealed box for nice, tight, accurate bass; a ported box for better "boom" and slightly more volume; or "infinite baffle," which really is no enclosure - the speakers use the entire trunk as an enclosure. This type has sound very similar to sealed box speakers and nice flat frequency response(that's a good thing), but the trunk must be completely separated from the passenger compartment or the sound waves will cancel each other (Hey, deja vu, I've written that before). Since Jaguar was nice enough to seal the trunk with that rear firewall we spoke of, my work was already halfway done. I chose infinite baffle both for this reason and the fact that a sealed box would have taken up valuable real estate.
Remember the goal - leave as much trunk space as possible. This is a departure from pure competition vehicles, they would think nothing of removing the spare permanently and filling the entire trunk with multiple amps and subwoofers, and maybe a waterfall. Not all that practical for a daily driver. OK, our trunk is our subwoofer enclosure so we need it sealed up as much as possible. We also need to dampen the sheet metal so it won't "ring," or vibrate with the bass. We want this car to sound good inside, not outside. The pictures at right show the right side of the trunk with the stock carpeted panel removed (it's the same as the left side). In the above picture there are several holes through this wall into the fuel tank area that need to be filled. In the lower picture we see the holes were covered with masonite and sound deadener sheets, then the whole wall was sprayed with aerosol sound deadener material. The front trunk wall was also done the same way.
The rear package shelf also needed lots of sound deadening. Mounting the subwoofers directly to the steel would have resulted in too much flexing and loss of "kick", so the shelf was reinforced with two layers of 3/4" Medium-Density Fiberboard. This wood is extremely dense and great for speaker enclosures. The funny shapes were needed because the Jaguar's rear shelf has a pan hanging beneath it in the center, where air is exhausted from the passenger compartment to the outside. The smaller pieces went on either side against the shelf, then the large piece connected them. The wood was glued together, then bolted to the shelf with (10) 1/4" bolts, and siliconed to be airtight. In the trunk picture three photos up you can just see the edge of the wood above the sunroof motor. The area around the speaker hole is painted black so it won't show through the grill cloth above. In the black area you can almost see the metal nuts embedded into the wood where the subwoofers attach so the wood won't strip out.
The woofer support was then covered with black carpet. The trunk has a shelf towards the front that is so far from the back of the car you can't reach it without getting into the trunk. I decided all components had to be forward of this point to avoid intrusion into the space you could reach. The shelf was covered with sound dampening material, then 5/8" hardwood was bolted over that. This allowed all the components to be easily screwed to the wood, while the wood and sound dampening provided a thermal barrier between the components above and the exhaust system below. You can see the forward wall of the trunk sprayed with the dampening material and the cellphone brain installed in the center. Next, the hardwood shelf was covered in gray carpet.
Since the power comes into the right side of the trunk and music signal from the left, It made sense to mount the rear battery on the right side. The wire from the front battery was terminated with a gold plated connector, then a matching 1-gauge ground cable was installed, grounding to a main unibody structure point. The photo shows the base of the battery enclosure attached to the shelf. Space was simply too tight to build it ahead of time, it had to be built in place piece by piece. The blurry silver thing at top left is the CD changer, now attached to the subwoofer shelf. Behind and below it relays are added for amp and equalizer turn-on, trunk lighting, and alarm system purposes. The black wiring on the right is stock, leading to the taillights and power antenna.
I'm pretty proud of this - the battery enclosure. Since the forward wall of the trunk was angled, there was more room at the bottom than the top. This made just enough space to tuck the capacitor behind the battery sideways. The capacitor stores energy for those intermittent peak power draws from the amp, such as big bass hits, that otherwise would momentarily dim the headlights while the battery tried to provide the power fast enough. This is a Stinger 1/2 farad cap, suitable for up to 500 watt systems. On the side of the box are two wiring blocks that split the positive and negative from the battery into 4 smaller wires to the components. I ran 4-gauge wire through a 75 amp fuse into the wire blocks, then 8-gauge from the blocks to the capacitor (shown here), amplifier, equalizer and accessories.
The battery enclosure was attached to the shelf, then the battery was installed and secured in place with carpeted front plates on the enclosure. This battery ain't goin' nowhere! Above it you can see one of the subwoofers, to the left is the amplifier now attached to the shelf. Behind the amplifier is a carpeted and mirrored panel that covers the forward wall of the trunk where the cellphone brain, relays, wiring, and crossovers for the rear-door speakers are mounted. It removes very quickly with two screws in case of problems. To the left of the battery are all fuses, including another 200 amp fuse on the wire leading to the front battery. The battery is a Stinger Dry Cell 800 amp unit, able to be mounted in any position.
Now that we have power, how about music? The preamp cables from the head unit are laying at the left side waiting for the equalizer to be installed. Positive and negative power wires are in place for the eq as well. Mounted to the forward wall is a vertical hardwood panel, covered in gray carpet, to which the crossovers for the front speakers are mounted. These take the signal from the amplifier and split it so that high frequencies go to the tweeters and low frequencies go to the woofers. All connectors are gold-plated, crimped and soldered. Above is the other subwoofer already in place. Between it and the CD changer are two switches that control the trunk lighting (more on this later).
Hey, this is coming together! A new floor over the spare tire well has been constructed from 1/2" plywood and painted black. It rests on weatherstripping material both to cushion it against rattles and to help keep any fuel fumes from coming into the trunk. Remember, the fuel pump and filter are down there with the spare. Oh, and yes, the spare tire well is well vented to the outside, Jaguar provided this already. The equalizer is now mounted next to the amplifier and all wiring is complete! The eq is an AudioControl EQQ 4-Channel unit. It separately controls the front and rear signals, with 5 bands of half-octave bass adjustment and 7 bands of octave upper frequency adjustment. Signals then go the amplifier, which takes the sub-bass out of all 4 channels and sends it to a fifth channel for the subs.
The amplifier is a Blaupunkt V7000 6-channel unit with internal crossovers, THD limiting and remote sub gain control. What's this mean? With crossovers inside the amp, I didn't need a separate crossover unit and connecting cables which cut down on space and cost. The THD limiting circuit will not allow a clipped (distorting) signal to be sent to the speakers (cool), and the remote sub channel gain control I mounted in the front armrest allows me to "pump up the bass," or turn it down at will. We'll talk amplifier power in a minute. This picture shows the cover panels under construction. I wanted all the wiring covered, but easily accessible, and I also wanted to show off my expensive components and gold plated connectors.
Wow, it's finished! Here's the right half of the whole thing. Plexiglass windows were installed into the cover panels, which were then carpeted to match the rest of the trunk. Lights were installed behind all the windows to highlight the components. Just to the right of the amplifier, that chrome handle lifts the removable panel over the fuses. It's made of plexiglass, bent and carpeted, then velcro-attached in place for quick access. Notice the panels come flush to the amp but leave all of the heat sink fins exposed for maximum cooling.
This is the other side, equally carpeted to match. There's a window to show off the crossovers, and another in the removable panel over the equalizer. This panel also lifts with a chrome handle to make equalizer adjustments, then reattaches with velcro. Under the amp I flush-installed a black textured plastic panel with a Jaguar emblem. No real reason, just felt like it. This picture also shows some of the blue neon light I installed behind the CD changer to light the entire area with a blue glow. Love that mirror behind the amp, too. New side panels for the trunk have been fabricated, carpeted and installed.
This is the works, with the removable panels removed. As you can see, I met my goal and kept everything up in the front of the trunk. The amp is exposed for cooling, the fuses and equalizer are easily accessible, everything is covered in matching carpet and the CD changer is easy to reach. It's hard to tell from this angle, but the CD changer is actually over a foot away from the amp. That's how deep this trunk really is! A bonus is that heat rising from the amp is not going directly into the CD's. Whaddya think? There's better pictures of all this on the Picture Page.
As for some specs I've forgotten, let's hit them now. The subwoofers are JL Audio 8IB4 8" drivers, especially designed for this infinite-baffle application. They are 8-ohm because I needed to wire them together in mono for a 4-ohm load on the amp. The amplifier is configured to send 40 watts to each of the front kick panel speaker component sets, 40 watts to each rear door speaker, and 200 watts mono into the subs. The amp delivers this power at .05% total harmonic distortion from 5 to 50,000 hz. Signal-to-noise ratio is 102db for the front and rear speakers, 107db for the subs. Incredible specs, but you really need to hear this system to believe it. The kick panel speakers are driven down to about 70 hz, which provides convincing bass-from-the-front imaging. I didn't think you could run 5-1/4" speakers that low, but these Quarts kick like crazy. They actually make your feet twitch on the drumbeats! The subwoofers, with all the bracing into the car's unibody structure, transmit their energy directly to the car's structure for extra kick. Don't think 8" subs can be enough? I disagree, it's all in the installation. These subs sound clean, tight, and powerful. You can play rap music if you want, and it will sound great, but that type of boom is not this system's forte. I wanted a system I cound listen to heavy metal with for headbanging, while also being able to fully experience everything in Tchaikovsky's 1812 Overture from the barely audible hand bells to the Civil War cannons firing. I think I succeeded.
Other electronic additions to the car include the cellphone system. All genuine Motorola, there's a quick-release cradle for the flip-phone, power to drive the phone and charge the battery while it's in the cradle, and a 3-watt power booster to the external antenna for maximum range. It can be used hands-free with the microphone at the driver's sunvisor and the speaker below the seat. I also installed an Alpine alarm system to protect the whole thing. It's got the normal stuff - underhood siren, starter disable, electronic shock sensor, and sensors on all doors and the trunk. It's also got a dual-zone radar sensor embedded inside the front armrest. This magical gizmo throws up one radar field inside the car, and another outside. Anyone dawdling too close to the car for too long will get warning chirps, while any intrusion inside immediately triggers the alarm. I've set it so I can occasionally park with windows or the sunroof open, and while pedestrians walking by are ignored, just sticking a hand through a window opening or the sunroof sets off the alarm. You could go a lot further with an alarm, but hey, if they want the car that bad they'll just drag it away with a wrecker while the siren blares happily away!
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