This article is about car audio amplifier wiring kits and what they contain and how to set one up in your car. The reason for wanting a car audio amplifier in your car is to drive a subwoofer or to deliver greater power and control to your speakers. Perhaps you want to have both a subwoofer and power your speakers from amplifiers. Whatever combination you want the fundamentals of what you need remain the same.

The first thing that you need to check is whether or not your head unit (cd player) in your car has a pre-out that (standard low voltage audio output) can be used for connecting it to a car audio amplifier using a wiring kit. This connection will be on the back of the head unit and will be phono connections which are red and white usually, although sometimes they are red and black. These are like the connections you can find on your home stereo or your TV. If you really don’t know what I mean then just Google phono socket and check out the pictures. If there are multiple phono connections on the back of your head unit then they will most likely be labelled. You will probably find front, back subwoofer and maybe AUX. The AUX connection will be an input, the others are all outputs to the relevant areas of your car. For the purposes of this article we will assume that you are using a head unit with a single output as this is what most will have.

When using a head unit with a single phono output the signal will most likely be switchable between full range and low frequency. Full range would output all the sound whereas setting for low frequency only would be the setting for connecting to a subwoofer.

There will also be a remote cable on the back of the head unit, this is usually coloured blue, but I would recommend checking. This information is either on the top of the head unit on a sticker or in the book that came with it. This remote cable tells the amplifier to switch on when the head unit is powered up.

The first thing that you should do is disconnect the battery so that you remove the risk of causing any damage to the car electrical systems. This is very important that you do this as some damage could be expensive to fix and it is always best to minimise risks. The last thing you want to do is blow some components in your new amplifier or set off some airbags.

The earth cable should be connected from the amplifier to the chassis at a point that is not painted, for example where something is bolted to the chassis. The earth cable is the big black or brown cable which should be the same gauge as the red cable.

The power cable which is the big red cable should be fed from near the battery to where the amp is situated, do not actually connect it to the battery yet. It is important to have an inline fuse installed somewhere along this power cable. Make sure it is somewhere accessible, typically near to the battery but that is not always possible. The important thing is that it is relatively easy to change if you need to.

The phono output from the head unit should be connected to the phono input on the amplifier using a phono cable. The phono cable is a twin run of coaxial wire with phono plugs on either end. When you run the cables make sure that the phono cable is routed a reasonable distance away from the power cable as this will prevent any interference.

The remote cable should be connected from the head unit to the amplifier also. This will be clearly labelled on the amplifier.

The speaker cable should then be installed. This is a twin run of unshielded wire, which is most likely quite thick. The power that will be used to drive the speakers will determine the required gauge of cable. When wiring up any speakers make sure they are wired the right way round otherwise you will invert the phase which will cause cancellation and a reduction in sound at certain frequencies. By this I mean make sure that positive goes to positive and negative to negative for all the speakers. If you are just wiring one subwoofer then this is not as critical as you can usually invert the phase using the amplifier which will solve the problem.

Once you have all the cables set up as described above it is wise to check them to make sure everything is right. If everything looks good then it is time to reconnect the battery and also connect the red power cable to the battery. Once this is done your new amplifier should be installed and working. All that remains is to set it up correctly but that is for another article.