Amplifiers are necessary to provide you with loud music but they also provide you with a much higher quality sound at all volume levels.

Before choosing an amplifier you need to know what kinds of speakers and subwoofer you will be running because your amp need to be able to provide your speakers with all of the power that they require. When figuring out how much power you will need from your amp look at the RMS power and not the Peak power of the speakers and amp. Choose an amp that is rated to supply power from 75%-125% of the total power need for your system.

If you are just going to be powering a subwoofer(s) a mono amplifier would make a great choice. Mono Amplifiers have built in bass boost, low pass filters and were designed with subwoofers in mind. An even better choice would be a Class D mono amplifier because they are much more efficient and run a lot cooler. You can also use a 2 channel amp to power 2 subs or use both channels to power a single sub.

If you are going to be powering a full range of speakers and subwoofers then you will need to use a 4-6 channel amplifier. This allows you to divide up the power your amp is supplying and give your speakers a channel and then give your sub multiple channels so that it will get the power it needs and you will not over power your speakers.

It is also important to look at the quality of the heat sink on the amplifier. The heat sink disperses the heat given off by the amplifier so that it can run efficiently. Some amplifiers even come with cooling fans that keep them even cooler.

To ensure the highest quality of sound is coming from your speakers you need to choose an amplifier that creates a high damping factor in your system. Having a high damping factor keeps your speakers from vibrating when they are not supposed to and keep your music extra clean and crisp. You can calculate the damping factor by dividing the impedance of the speakers by the output impedance of the amplifiers.