There are many ways to build an awesome home theater system. You can go the traditional route of buying an AV receiver and multiple speakers. You can buy a home theater starter kit (also known as "home-theater-in-a-box"). You can buy a soundbar then — by adding satellite speakers and a wireless subwoofer— turn into a wireless surround sound system later on. You can even buy something like the Sony HT-A9, which is a completely different kind of surround sound system.
No matter which route you take, it's also important to have a basic understanding of multi-channel systems. For instance, what's the difference between a 2.0 and a 2.1 system? A 5.1 and a 5.1.2 system? A 7.1 and a 5.1.4 system?
We've asked Rob Brennan, the technology manager for home entertainment and sound at Sony Electronics, to help break it all down as well as give some buying advice on which home theater configurations make the most sense for you.
Let's dive in.
What do the numbers mean?
In simplest terms, there are three numbers (and two dots) in every multi-channel system. Let's use a 5.1.2 system as an example. The first number represents the number of speakers at your ear level. The first three (so a 3.0) represent the left, right and center channels, and the second two (to make it a 5.0) represent the rear satellite speakers. The middle number (the "1" in the 5.1.2 example) represents the number of subwoofers. And the last number represents the number of height-channel speakers.
There are a couple other things to point out in regards to these numbers:
• First, if you have a system with only two numbers, like a 2.0 or a 5.1 system, that simply means that the third number is zero — there aren't any height-firing speakers.
• Second, height-channel speakers (also known as up-firing or top-firing speakers) can be one of two things. They can be speakers that are physically installed in your ceiling or they can be upward-firing speakers, usually in your soundbar or placed as "toppers" on bookshelf or floorstanding speakers, that shoot sound upwards so it reflects back down off the ceiling. Both help create a greater level of immersion.
• Third, you can have multiple subwoofers in a home theater system. The advantage is that it helps more evenly spread low frequencies around — especially in a big room — so there are no dead spots. According to Brennan, however, because each subwoofer gets the same signal and does the exact same work, the middle number can only be "1." For example, a 5.2.2 system is still really a 5.1.2 system (but one with two subwoofers).
A New Age of Home Theater Systems
In terms of home theater systems, there's been a big change in how audio is engineered and mixed due to the emergence of immersive sound technologies, specifically Dolby Atmos and DTS:X. "We've gone from a channel-based audio mix to an object-based audio mix," explained Brennan. In a channel-based system, engineers assign specific sounds to specific speakers. While with object-based systems, sounds aren't inside of speakers anymore.
The advantage of object-based systems that support technologies like Dolby Atmos and DTS:X, is that sounds can be made to appear in more specific locations. "Essentially the engineer has this kind of three-dimensional bubble and they place these objects (specific sounds) in space," said Brennan. And the more speakers (or channels) you have in your home theater system, the more accurately you can get specific sounds to appear exactly where you want them.
The Beginner Home Theater System: 3.1
A 3.1-channel system is an entry-level home theater system that solves one of the most common problems that people have when just using their TV's built-in speakers: poor dialogue. A 3.1 system adds a dedicated center channel speaker, which Brennan says allows for better control, as well as better projection of dialogue and the main audio of whatever it is you're watching; the action and the main music— that's all coming from the center channel. With the subwoofer, it adds support from the low frequencies as well.
The good news is that there are a lot of 3.1-channel systems out there. In fact, there a lot of soundbars that are in fact 3.1-channel systems, with dedicated right, left and center channels. The main downside is that with only three speakers, even if the 3.1 system supports immersive technologies (which it likely does), it's not going to place those object-based audio effects as accurately as if there were speakers.
"Any speaker system can fake it," said Brennan. "We can manipulate the timing, frequencies and the phasing of sounds to make them appear to be in front of you, behind you, above you or below you — that's just the frequency manipulation. And so we can do those sort of tricks, even with a 3.1 system where all the speakers are in front of you, to make it seem like some things are behind you. But it's not as accurate as then going to a 5.1 system."
The Best Home Theater System for Most People: 5.1
A 5.1 system is simply an 3.1 system — so left-, center- and right-channel speakers, and a woofer — with the addition of left- and right-rear speakers. The big benefit is that the rear speakers add an even deeper level of immersion.
"Physical speakers will always more accurately produce sound behind you than the phasing manipulation that can happen [without them]," explained Brennan. "So it creates more accuracy and more envelopment, and it's certainly better for larger spaces and that's all that happens. In a 5.1-channel system, the two rear-channel speakers are recommended to be placed at around ear-level and directly across from their opposing left and right front-firing channel speakers.
"[A 5.1 system] is what I would consider to be the most popular home theater surround sound standard — that's pretty accessible for people," Brennan said. "You can add two speakers to a 3.1 soundbar and you can get to that 5.1 standard pretty quickly without a whole lot of cost or annoyance."
The Upgrade Home Theater System: 5.1.2
If you're serious enough to want to go beyond a 5.1 system, you've got options. You can upgrade to a 7.1 system, which adds two surround speakers (or speakers that get placed behind you and to the sides of your existing rear speakers) or you can go to 5.1.2 system — the latter of which is what Brennan recommends.
"For a lot of people, doing a 5.1.2 would be more impactful than a 7.1," Brennan explained, "Because you can take more advantage of that object-based audio." The "dot two" in a 5.1.2 system represents the overhead or up-firing speakers. These are speakers that can even better take advantage of content that is mixed for Dolby Atmos and DTS:X because, once again, physical speakers are better than gimmicks.
Overhead speakers are height-channel speakers that you place in your ceiling, which is probably more than most people want to do. An easier option is getting a system or soundbar with up-firing style speakers, which do effectively the same job — by they fire sound upward so that it reflects off your ceiling and back down towards you (the listener) — without having to cut holes in your ceiling or drag wires.
You can go a lot further than just a 5.1.2 or a 7.1 system, of course. You can add more height-channel speakers (which would, for example, take you to a 5.1.4 system) or another woofer.
"For my money and from my personal experience, a 3.1 [system] is a great place to start because it solves a lot of pain points that people have, but I don't know that I would ever call it a home theater system," said Brennan. "A 5.1 is what we are really talking about effective, really effective immersive audio. And then if you want to go beyond that, start thinking up before you start more [speakers] around because that's the next biggest improvement is to take full advantage of height-based audio."