Alfa Romeo Giulia Bass Upgrade with Custom Enclosure

A former colleague from the mobile electronics industry contacted us about upgrading the bass in his son’s new car. He wanted to add subwoofers, an amplifier, and a custom enclosure to his son’s Alfa Romeo Giulia. We were honored that the client chose us to work on his son’s car and set up a time for him to drop it off.

Client’s Goals Are Our Goals

When planning a custom build, we always ensure to get as much information from the client as we can to help define the parameters of the build. In the case of this Giuila, the client wanted to make sure the enclosure did not block the opening of the trunk floor access panel. In this car, the battery and main fuses are under the trunk floor, and the client wanted to retain easy access to them.

Equipment Planning

We chose our small enclosure secret weapon because we weren’t going to have a huge amount of room and the client wanted quite a bit of bass. Our small enclosure secret weapon is the JL Audio 10tw1 subwoofer. The 10tw1 subwoofer is one of JL Audio’s thin subwoofers that works well in enclosures as small as 1/3 of a cubic foot. After careful measuring and a bit of plotting on our Term-PRO Enclosure Design software, we determined that we could fit two of the 10tw1 subwoofers in a vented enclosure within the constraints the client gave us. We would even have a bit of space left for some custom trim panels!

Electronics Installation

Measuring the factory response revealed a less than optimal response curve.

The electronics were mounted in a factory storage pocket.

We mounted the fuse holder on a vertical bracket in the trunk.

We laser-cut a custom trim ring for the bass knob.

We started the installation by tackling the electronics part of the job. When we are integrating bass with a vehicle we aren’t familiar with while retaining the OEM radio, our first step is to analyze the factory signal response of the radio. Looking at the response of the Giulia radio on our JL Audio MAX measurement system, we found that there was a gradual roll-off of bass on the low end of things. To help flatten out the bass reduction, we use a Wavtech integration processor that has a bass contour feature. The bass contour allows us to add back in some of the bass that the factory radio was filtering out.
The JL Audio amplifier wiring was pretty straightforward and didn’t take much power wire, as the battery is in the trunk. We securely mounted the fuse holder to a factory bracket and neatly routed the wiring. Both the amplifier and the Wavtech processor were mounted on a board that we constructed to drop into the factory storage space next to the fuse block.

Custom Enclosure Fabrication

Folding the center armrest down reveals the plate we laser-cut.

We didn’t want to leave the front of the enclosure plain!

We love adding small details to our builds!

The basic enclosure was the first part of the trunk build.

The enclosure front has threaded inserts in it to allow the trim plate to bolt to it.

Two Aeroports were used to minimize any unwanted port noise.

The honeycomb grilles were made with layered acrylic and attach to the enclosure with magnets.

A strip of blue LED lighting was used to light up the woofers.

The front trim bolts to the enclosure, and the honeycomb trim panels magnetize to the plate, covering the bolts.

The trunk looked great, sounded great and still left the client access to the factory fuse block.

We think the enclosure looks even better than if the factory had designed it!

We wanted everyone to know who built this awesome enclosure!

The blue LED lighting helped to highlight our logo on the enclosure.

The honeycomb inserts add a unique look to the enclosure.

The blue lighting helps to highlight our logo.

The trunk fabrication was next on our list of things to do on this Giulia. We started with the basics of building the custom enclosure. To maximize the airspace in the enclosure, we use Aeroports to port the enclosure. These tube ports are constructed of thin plastic, so they don’t waste too much airspace in the enclosure. Two extensions were added to the front of the enclosure, and they were smoothed into the face of the box.
The rear seats in the Giulia have a center armrest that folds down. In the instance of this car, there would be no skis going through the opening, so that would just leave the backside of our enclosure visible. We laser-cut a trim plate for the space and etched it with some decorative lines. The top of the plate has a circular cutout for an Alfa Romeo badge and a blue trim ring. We also laser-cut cut a thin wood outer trim ring that we molded into the back of the box. This trim ring provided a spot for the trim plate to drop into and flush into the enclosure.
Our plans for the enclosure included some lighting that would highlight the woofers. To help enhance the reflection of the light, we upholstered the front of the enclosure with a light-colored grey vinyl.
Next, we began construction of the outer trim for the enclosure. The client wanted the enclosure to look like it was part of the car, so our outer trim ring followed the contours of the trunk sides. To add more detail to the trim ring, we used a series of layers that were upholstered and painted. Flanking each of the woofers are laser-cut accent pieces. We cut honeycomb-shaped thin acrylic pieces that were overlayed on blue carbon fiber look vinyl. The final accent pieces were an upper acrylic plate that housed another Alfa Romeo badge and a clear acrylic piece with our laser-etched logo on it.

Another Great Result and Happy Client

Knowing that the OEM signal was taking a bit of bass out of the signal, we weren’t 100% sure what the performance of this system would be. We knew we did our best, and thankfully the results were impressive. The client loved the way the custom enclosure in the trunk looked and also thought the bass was impressive. We love to build one-of-a-kind designs for our clients. If it is time for you to dress up your trunk or add more bass to your vehicle, stop by or contact us here.