Each car music device has some sort of amplifier, but most of it is made up of head units. If you have ever ramped up the stereo volume and heard a lot of distortion, it is presumably due to the built-in, underpowered amp.
So how many sources will you use, then?
Amplifiers are available in a range of different setups, and the number of speakers you have or your sound system depends on how you choose the right amp for speakers.
In general, every speaker you want to enhance requires one sound. If you add a subwoofer to an existing network the work should be done by a single channel amplifier.
There are also mono amplifiers in Class D series which are specially designed to use less power and heat when amplifying subwoofers.
The two-, four- or six-channel networks are more versatile. You can either control two coaxial speakers or two woofers using a two-channel amp, or you can use two sets of coaxial speakers to transform it into one stand.
Whether you want to install a subwoofer to give your full-range speakers extra power than a four-channel amplifier can do the job.
You can run any full-range speaker off your own screen in that situation, and then connect the other two to power the sub.
Alternatively, the same system should be used to power the four coaxial speakers and then connect the subwoofer to a separate mono adaptor.
Component systems may be more flexible and may require multiple amplifiers, external crossovers, and other parts.
Do not skimp on research
If you are trying to get the pick the right amp for speakers of your car stereo, it is important you do not put your speakers underpowered.
That is why many people are first picking up speakers and then having an adapter to give them enough power to power them.
If you are only dealing with your factory speakers, you can always consider the value of RMS (root mean square) and then select an amp that can produce at least 75 to 150 percent of that volume.
Energy is also a problem if you are looking to run a sub off the same amp with which your speakers work. Bridging two multi-channel amp channels can have adequate power to run a sub but it is not suitable in any way.
If an amp cannot meet your specific subwoofer control needs, then it is best to look for another mono amplifier that can do the job.