Adding Subwoofers

Adding a sub is the point where your system will move to a new level. The extra low end punch will make the overall sound much more like you'd hear on a home hi-fi and then some!
To run a sub, you'll need to use an external amp as your head unit won't pack enough power to drive the sub. The sub will also need to be mounted in a special enclosure. The size of the subwoofer's speaker cone, the magnet configuration driving it and the type of enclosure that it is housed in all have effects on the resulting sound.

Choosing a Subwoofer Cone Size

Subwoofers are available with code diameters ranging from 4" up to 15"with some specialist models being available with even larger cone diameters.

However, in the small Arosa your limit will probably be 12" maximum (this
may even be pushing it!). An 8" or 10"(size I have) would certainly be sufficient, but if you wanna go mad two 10" subs will do the job!

The cone size is a factor in each the potential volume of the speaker, the sound quality reproduced by it, and the power required to drive it.
Generally, smaller subwoofers, 8" to 10", will produce a higher quality sound than larger units when powered by the same amp, but they wont be able to reach the extreme low end of the sound range, or produce the same sort of volume that larger units can, although larger units require a more powerful amplifier to provide a similar quality.
10" and 12" units provide a good balance between quality, volume and frequency range, with the 12" having the edge as long as it's powered by a suitable amplifier.

Enclosure Types

There are three differing types of sub enclosure to be considered.

Sealed enclosures will provide the best sound quality although they wont produce a very high volume unless driven by a powerful amp.

Vented (Ported) enclosures allow the box to be fine tuned to respond to a certain frequency. This can be useful if you listen mostly to a certain type of music and can set the system up accordingly, but sound quality on other music types will suffer as the sub wouldn't respond that well outside the frequency that the 'port' is tuned to.

Bandpass enclosures basically combine the two types to produce a louder sound without sacrificing too much quality. However, this means that more space will be required to install such a box and a high power amplifier will be required to drive it. Not really recommended in the Arosa
as boot space is very limited.

Active Subs

There are a few active subs on the market (the most common and best being Vibe). These have built in amps and can be perfect if space is limited as in the Arosa. They are easy to fit as well not needing an external amp. I recognised the advantages of these and opted for one of them.

Some people may argue that they won't produce as good a sound as separate a seperate sub and amp but I am still extremly impressed with mine. It has also been highly rated by our fav mag(?), Max Power. Just don't go for really cheap active tubes as these rarely produce a good quaity sound with depth and power.