Amplifiers aren't just for making your music louder. The extra power will make your music sound more clear and full-bodied, even at lower volumes. And if you do like it loud, the added power of an outboard amplifier is exactly what you need.

How to choose an amplifier

You'll see a lot of options when choosing an amplifier, and making the right choice depends on what you're trying to do:

• Want to add more power to your factory stereo and speakers? Choose a 4-channel amp of 45- or 50-watts per channel, and make sure it has speaker-level inputs.
• Trying to power a subwoofer or two? Get lots of power with a mono- or 2-channel amp.
• If you want to power your speakers AND a subwoofer, then you need a multi-channel amp with four (or more) channels.

Below, we'll briefly explain the different types of amplifiers and some of their key features. For more details, read our car amplifier buying guide.

Types of car amplifiers

Each "channel" of an amp is a discrete source of power intended to power one speaker. There are ways to use one channel to power multiple speakers, but be careful, this is an advanced trick. You can also combine two channels to power a single speaker. This is called "bridging" and yields a lot more power than the channels would produce separately.

Mono amps -- If bass is your primary objective, take a look at these amps. Single-channel amps or "monoblock amps" offer maximum bang per buck for driving subwoofers. They offer simple system configuration and more power at lower impedances.

2-channel amps -- These amplifiers are used for driving two speakers (great for ATVs or old pickup trucks, for example). They can also be switched to mono mode to power a subwoofer.

4-channel amps -- 4-channel amplifiers offer a lot of flexibility for powering your car audio system. You can power all four of your car's speakers, or you can use two channels to power your front speakers and the other two channels to power a subwoofer box.

5-, 6- and 8-channel amps -- These amplifiers give you "full system" power in one box. A 5-channel amp has four channels to drive your four speakers, plus a fifth, higher-powered channel for your subwoofer. These amplifiers are a popular option for anyone who wants a system with a simple configuration and minimal loss of cargo space. 6- and 8-channel amps offer even more flexibility.

Compact amplifiers -- These tiny power packs fit in small, out-of-the-way places in your vehicle, so you can put big power where it would never fit before. They're great in small cars. The 2-channel versions are popular with motorcycle owners.

What to look for in a car amplifier

Speaker-level inputs -- Special type of inputs that let you connect the amp to a factory radio.

Built-in DSP -- All amplifiers have controls for basic sound adjustments. Amps with a built-in digital signal processor (DSP) give you much more sophisticated sound adjusting tools, typically via an app for your phone or tablet.

Bluetooth connectivity -- The ability to wirelessly stream music from your phone to the amp.