An amplifier allows you to increase the volume of installed speakers without sacrificing clarity. Your car’s radio has a small built in amplifier that does not produce a lot of power. Better speakers require more power to run efficiently and an amplifier provides that power.

While most people think power is only needed for volume, excess power is also needed to accurately recreate fast transients such as a cymbal crash or other dynamic change in sound output. Without enough amplifier power, the signal is clipped resulting in distortion.

Read more at Why Add a Car Audio Amplifier? and Two Common Car Amplifier Power Mistakes.

Choosing an amplifier can seem like an overwhelming process with so many choices but answering a few questions can help you make the right selection quickly and easily.

• Are you going to connect a subwoofer or speakers to the amplifier? If you are going to connect a subwoofer(s) to the amplifier you are going to want to use a single channel, mono block, amplifier to take advantage of its better efficiency. If you are going to be connecting full range speakers you are better off selecting a 2 or 4 channel model as they use class A/B design which delivers the best sound quality. If want to connect subwoofer(s) and speakers to the same amplifier then you want a 5-channel amplifier.
• What is the RMS power of the speaker or subwoofer(s) you are connecting and what is their impedance? Select an amplifier that most closely matches the RMS power rating of your speakers or subwoofers at the same impedance to ensure they will work. For example, if you have coaxial speakers that are rated at 60-watts RMS and have a 4Ω voice coil, you will want an amplifier that outputs close to 60-watts RMS at 4Ω. This information is available in the specifications tab of each part.