Competition Corner - April 2004
by CAE, Feb 24, 2009
We've spent a lot of time over the last several months showing the build-up of the Alpine Civic show car, and we finished it up last month. As you guys might have guessed, we've been working on the new 2004 show car for some time, and we'll begin covering the construction of this monster soon enough. While we spend lots of time and money on these show stoppers, it's also important to show more real-world applications of our products. For the Consumer Electronics Show in 2004, we decided to turn a 2004 Honda Element into an affordable, practical show car that contains a relatively inexpensive yet awesome-sounding Dolby Digital 5.1 system. This is also a good example of a really nice system that can be built on a realistic budget, saving both time and money.
The focus of this system is the performance of the products, so we're going to keep the install relatively simple, yet attractive. Also, we don't want to take up too much space, since this is designed to be a practical automobile. The most important concern when designing a sound system is speaker placement, so we decided to mount five midrange/tweeter combos in optimum locations for the best possible multi-channel experience. For Dolby Digital 5.1 and DTS systems, it works best to use identical speakers for the front, rear, and center channels, and to mount them as close to ear level as possible. Equal path lengths aren't quite as important as with a two-channel system, since the encoded signals will ensure a good soundstage for both driver and passenger.
The front left and right speakers were mounted high in the A-pillars, using the stock plastic A-pillar trims to form the basis of the panels. Holes were cut in each one to allow the mids to protrude through, then the panels were sanded with rough, 36-grit sandpaper to make sure the fiberglass would adhere to them. MDF rings were then made on the router to hold the midrange and tweeter combo. We decided to use the grilles that came with the speakers, rather than making custom grilles, to save time and installation labor. The rings were attached to the plastic panels temporarily with superglue, which holds them well enough until the panel is finished. Grille cloth was then stretched tight and stapled to the panel, giving it a three-dimensional shape. Fiberglass resin was then applied, and five subsequent layers of fiberglass mat laid down to strengthen the panels. This is the same technique we used to build many of the Civic panels, just on a smaller and simpler scale.
The rear pillars were formed in exactly the same way as the front ones, creating front and rear speakers that are high and as far to the outside corners of the car as possible. This was a great start to our 5.1 system, but we needed one more thing to finish up the soundstage -- a center channel. A properly performing center channel is absolutely critical to a multi-channel system, so we mounted an identical mid and tweeter in the middle of the dash to bring the soundstage alive. An MDF ring was molded to the top of the dash using Duraglass then the tweeter was placed in front of it on the radio bezel. These pieces were fitted together nicely to better integrate the large center channel into the interior of the Element.
With the speakers in place, it was time to tackle the rest of the fabrication on the front of the car. The factory double-DIN radio gave way to a flip-out DVD unit along with an MP3 hard drive player. The dash panel was sanded down and ABS plastic was used to integrate the two units into a space previously occupied by one. Duraglass was then applied to perfectly fit both units into the dash for a factory look.
Since our Element would also need to entertain the rear passengers, we decided to place a second DVD player between the front seats, as well as add a pair of headrest monitors. The enclosure for the DVD unit was built by bending and super-gluing ABS plastic together, which is a quick and efficient way to form many types of small panels. More ABS was then attached to the outside of the piece to add some style, then some Duraglass finished up the shape and fit of the piece.
The last element of our, uh, Element was the rear hatch area. This space needed to house the 12" subwoofer, two amplifiers and two video screens. We started by building the 3/4-inch MDF sub enclosure, a simple 1.2-cubic-foot box mounted in the bottom of the spare tire well. We didn't want to use all of the spare tire well space, since we would need some of it for mounting electronics once it was time to wire the system. A 3/4-inch MDF frame was built to fit the stock rear area of the car. The amps were mounted on welded 1/2-inch tube steel braces, which were then welded to the car. The frame for the rear panels was then made using MDF and superglue, cutting individual pieces to make the desired shape.
That's it for this month, so check out next month's column when we finish up our Honda Element. Check out SteveBrownUniversity.com, and send any questions to sbrown@alpine-usa.com.
