To help you decide exactly how many channels you need for your home theater system, here’s a breakdown of each channel speaker system.

2.0 and 2.1 Channel Systems

Your basic stereo system (a 2.0 system) has two channels of sound—left and right—produced by two speakers. A 2.1 channel system adds a subwoofer into the mix for extra warmth and bass, often a necessity for a music listener who prefers speakers to headphones. Every speaker system that ends with a “.1” includes a subwoofer, as it’s not considered a speaker, but still an important part of the speaker system. A 2.0 or 2.1 channel speaker system is by far the most cost-effective setup, and it’s well-suited to smaller spaces or to a space that you don’t want to get too loud, a common side effect of outputting sound to several speakers.

5.1 Channel Systems

A 5.1 channel speaker system brings an additional three speakers into the fold: a center speaker as well as two other speakers that can be positioned to the sides or back of the center speaker. Traditionally, the center speaker handles dialogue, music vocals, and UI interactions in games while sound effects and instrumentation go to the front-left and front-right channels, and in whatever you’re watching or playing, whatever’s going on behind or to the left and right of what’s happening onscreen will be piped to your back-left and back-right or side-left and side-right channels. Almost all music is recorded in stereo (recorded to playback in more than one speaker channel). Much older music may be in mono (recorded to playback in a single speaker channel), and some niche artists create music for more than two channels for a surround sound listening experience. So, if your main interest is music and not movies, TV, or video games, a 5.1 system with an additional three channels will likely be overkill.

6.1 Channel Systems

As you might expect, a 6.1 channel speaker system adds another speaker on top of a 5.1 system: a center speaker that goes in the back. With 6.1 systems, the speakers in a 5.1 system that can be positioned on the sides or back will be positioned at the sides for a true surround sound experience. 6.1 speaker systems are uncommon in the audio world with most people opting for either 5.1 or 7.1 systems when considering an investment in surround sound. This is because 5.1 systems can easily become quite expensive, and the savings that a 6.1 system brings over a 7.1 system is relatively insignificant, but the benefits of a 7.1 system over a 6.1 system can be significant. So, while a back-channel speaker will definitely be more immersive than without one, a 7.1 system is even better and often exists at a price point where the difference in cost of a single speaker is negligible compared to the cost of the rest of the setup.

7.1 Channel Systems

Considered the best of the best when it comes to a home theater setup for audio, a 7.1 channel speaker system adds a final speaker on top of a 6.1 system for two front channels, a center channel, two side channels, two back channels, and a subwoofer. As compared to a 6.1 system, a 7.1 system has a back-left and back-right channel while the 6.1 system has a back-center channel. Two speakers in the back distribute directional sound a lot better than a single center speaker. This will be most pronounced in something like a video game where you can use your back channels to pinpoint exactly where a sound in the game-world is coming from. In the context of movies and TV shows, the benefits will be less pronounced but will work in a similar way: it will be easier to hear and differentiate between sounds coming from behind you.