having looked on the internet read the 50 / 50 comments on them i decided to track one down as i wanted a small install with as little modding as possible.
found a few examples of bose systems from scrap cars mainly audi these A3 sub units sit on the rear wheel arch and act as a small subwoofer.
Bought the A3 subwoofer for ?20 tried running it direct, worked in a fashion hardly booming in the box. I then tried fitting this to the rear arch of a mk1 golf, with some cutting of the brackets the subbox would fit except the direction of the sub speakers faces the boot lid.
Found an alfa romeo bose subwoofer, bought this one for ?60 this is a larger box but has a side facing single sub about 150mm hardly massive bought fits nicely under the rear shelf to the right reducing the boot slightly.
the amp on this was huge, opening the unit it up and trying to trace 21 odd pins on the unit was a nightmare, the amp itself was a 5 channel system, wires going everywhere on closer inspection it looked like someone had worked on this amp so the chances of it working were slim and i didnt want all the extra channels sold this off to cover the cost of the subwoofer.
The A3 subwoofer however has two naff speakers but a rather tiny amp inside
the amp is 100watts stereo hardly ear shattering but it runs at 1 ohms and the 150mm sub rated in at .5ohms.
To connect the bose amp required opening the amp and tracing the wires this amp has 7 wires. 4 for the speakers 1 live, 1 trigger live switch and 1 earth.
i initally connected this to the aux on the back of a old head unit, worked a treat except it popped each time you changed tracks, so it seemed to start and stop the amp.
i then bought a kenwood amp mono running at 2 ohms and tried this on the subwoofer the sound was crap at least a quarter of the power less.
took the kenwood amp back and decided to stick with the popping bose amp, instead i wired this direct off the rear speakers of the unit and it works a treat no popping nothing, you only have to turn the volume up a notch and the bass is there, the crossover in the amp does a good job and the sound is impressive for saying the subbox is about twice the size of a shoe box.
if you cant find the bose amp you can mount a choke on the back of the speaker to increase its impedance so that it can be run on normal amps.
you can get no end of these bose systems off the internet if you fancy something different the speaker you need is called a RichBass speaker they will be only one of these in the box these run at .5ohms, the stereo versions have two tiny sub speakers which are piss poor these run at 2 ohms. the easiest to wire up are the enclosed amp units from audi's you can also obtain adaptors for these.
total cost came to ?30 after selling the alfa amp and the spare empty A3 subbox
