Adding a Subwoofer

I very clearly remember the quality of the radio system that I had in my original spider in 1968. It was a mono AM-FM five button radio that played through a 3X5" single speaker under the radio playing through the grill in the radio console.

Pretty much no bass, and you could hardly hear it with the top down at 70mph. On a trip from Orlando to Whichita it was more than the poor little 3X5 could bear and it died. That next summer I installed a comlicated multiplexer for the Tenna radio that gave me a seperate amplifiers and even a "stereo" light that worked. Two four inch speakers went into the map pockets and I thought I had something pretty special. My how times have changed.

Today, head units put out 45 watts per channel and have four amplifiers capable of impressive volume and can be heard at any speed. There is an incredible amount of additional equipment that can be purchased thru the aftermarket that can enhance the sound of any car stereo system and over the last three years, much of it is being down-sized to fit the small compact cars that are available now. I guess we have the Honda Civic and Miata crowd to thank for this.

We've installed Kenwood midrange MP3 head units in most of the cars and are happy with the quality of sound, but the small speakers though producing a lot of volume, arn't up to the bass output of modern systems. Over the last couple of years, we've experimented with three different solutions.

First we added a "boom" box on the back seat with twin 8" speakers (visible in the final install picture) and this provided a pretty good midrange and the small tweeters provided some additional top down sound to overcome wind/engine noise, but there wasn't a lot of bass and it needed an additional amplifier to get any punch out of it. There just wasn't room that we wanted to give up for that sort of installation, and though it would look nice, doesn't fit well with the character of the car (opinions vary).

Second we tried a Basslink powered subwoofer. This was the first really "small" amplified subwoofer. The tube Bazooka style subs take up the whole back end of the spider, so we gave the Basslink a trial fit. It is a 10" 200watt driver/passive radiator system, that just plugs into your rear speakers, or low level (RCA) outputs from your head unit and hook it up to the battery and a small remote volume control and that's all there is to impressive bass. We currently have them installed in the big travel van, and the Bronco, and they work great. Lots of sound, self contained, and the are relatively small, about 14X14X10"tall. The Basslink almost fits between the Fiat seats in the back, but takes up the whole area, and invites being stolen as it is very visible. So we mounted it in the trunk. Sounded good a car shows with the trunk open, but left something to be desired when on the road, which is why we bought it.

Third, we purchased a couple of Kenwood powered subs known as the WooX. Sounds kind of strange, but these small subwoofers put out an amzazing amount of sound out of a small 5" woofer with a 6" passive radiator. The advantage as you can see from the picture is that it can be mounted right behind the driver and is mostly covered by the top cover when the top is down. By mounting it in the passenger compartment it makes it easier to hear than having it in the trunk. It also doesn't take up much room behind the seat as you can see from the picture, it wedges into the area between the seat and the door. Click the picture on the right for another view.

The bass response of these units is pretty amazing. They have very long cone excursions and when whey are really pumping, the cone bounces back and forward at least a half inch. The main limitation of this small sub is ultimate volume. We tested the unit with a test disk and it has a useable low range down to about 40hz, the front kick panel speakers gave up around 90hz, and you could hardly hear them. The WooX was just coming into it's element. It really adds a lot to the bass drum and bass parts of songs that we don't hear in Fiats. Clarion makes a similar unit in size to the WooX, but we didn't have a good source for one, they are a bit more expensive, and we wanted to stick with Kenwood to make the system match.

Out on the road, and around town, the sound is so much better than what you are used to in these cars. On the highway above 70mph, you won't be able to hear it much with the top down, but at 55-60 it is still able to come over the engine, wind and road noise.

There is a wired remote control to adjust the output of the sub, the crossover frequency, and the phase of the unit. we jut put it on the floor in front of the drivers seat. You can click on the image for a larger version. There are times when you want to turn it down on some kinds of music and this makes it nice. The remote control is not required to operate the sub.

Installation is very easy. We ran a power line from the battery in the trunk, we tapped into the activation line for the antenna to turn on the sub's amplifier, and hooked up the rear speakers to the speaker input on the sub's port panel. By using the remote antenna control to turn the sub on and off, we avoid running the battery down inadvertently. We had already run speaker wires to the "boom" box so we just tapped into them and left the unused wire concealed under the seat.