Home Theater Channels Explained
When you are shopping for a new amplifier and speakers to match your home entertainment system, one of the specifications that is likely to catch your attention is the number of audio channels i.e. channels of control voltage for each amplifier.
The number of channels will determine the number of speaker sets you’ll be able to power with each channel of your audio/video amplifier.
But what about the .1?
Many people mistakenly assume that the .1 in 7.1 indicates that there are .1 channels in a 7.1 speaker setup. But let’s first take a look at how the audio tracks are encoded on a DVD, CD, or Blu-ray disc. Your typical DVD player or Blu-ray player may be able to play back audio in one of three ways: Dolby Digital, DTS, or PCM. Each of these encoding methods is responsible for detecting and playing back the sound using a specific number of audio channels.
The thing to remember to about surround sound channels is that they are encoding channels, and not playback channels. The PCM format can encode up to 8 channels of audio including left front, right front, left back, right back, center, left surround, right surround, and left or right sub. The Blu-ray standard supports Dolby Digital 5.1 or DTS, which can encode 6 or 7 channels of audio, respectively.
Other Speaker Terms
Although the term audio channel may sound complicated, it’s actually very simple.
Basically, how many speakers you have is referred to as the number of audio channels. It’s the number of speakers connected to your audio/video receiver that deliver sound. So, if you have 5 speakers in total – 2 front (left and right) and 3 rear (left, right, and center) – your system has 5 audio channels.
When buying speakers, the most common audio channel types to look for are 2 channel, 3 channel, and 5.1 channel amplifiers. However, you can also find 6.1 channel amplifiers, which consist of 2 additional subwoofer channels. And more recently you can also find 7.1 channel amplification, which contains two additional channels for surround sound. The additional channels help to enhance realism for an immersive sound experience.
Here’s a breakdown of these amplifier types:
Ohms, volts … Oh my! What do all these mean?
The fear …, THE JARGON, is over at last.
One of the little secrets of the home theater audio world is that the rule of thumb for placing speaker placements is only that … a rule of thumb. That’s why you see people putting speakers in all kinds of places, even where you would not expect them to install a speaker in your home theater.
In fact, for a lot of home theater installs, the whole rule of thumb scheme doesn’t really apply.
This means that those who are clueless about AV equipment and wattage can install their own home theater and even do it themselves if they have a few friends who are technically sound.
Getting the AV equipment right makes a huge difference to the output of your home theater. In fact, high quality home theater audio goes beyond playing the latest movies and being able to hear every detail from the sound effects to the dialog. In order to get all this output, most of the noise and unwanted sound in the environment has to be filtered out.
The impedance rating is how much electrical resistance the amplifier or receiver has to work against to produce that sound you hear.
It tells how much power an amplifier or receiver will need to output to the speakers in order to get a specific amount of audio output. The two main ratings are "low impedance" and "high impedance".
A low impedance speaker is under 4 ohms and a high impedance is over 6 ohms. The impedance is what comes in to play when matching your speakers to your receiver or amplifier. While impedance doesn’t have a direct correlation to the quality of sound, it does play a role in how much power is needed to make the speaker operate. The amplifier or receiver can’t produce more than it needs and the speakers can’t receive more than they can handle. Speaker and amplifier manufacturers list the impedance value of their products for this reason.
So if your speaker “ says you need a 20-watt amp for example — a low impedance rating of 4 ohms would mean you could use an receiver or amplifier that outputs a maximum of 20 watts per channel. But, an amplifier with a high impedance rating of 8 ohms would have to be driving twice the power (40 watts) to produce the same volume.
The benefits of home audio and surround sound systems are obvious – your best entertainment is available to you not only at home but outdoors too, provided you have access to electricity and an outlet.
While what you're watching or listening to is often the primary concern with entertainment media, the quality and consistency of the sound and video you're experiencing are important too. The digital age has brought with it a range of benefits and challenges that, for the most part, have improved the entertainment experience. But the introduction of gimmicks, new formats and murky industry lingo has created confusion and frustration for consumers.
Fortunately, the use of confusing terms in home audio has been pretty minimal, with the major players making it easy to understand their products. But for a beginner, there can still be some confusion when it comes to audio terminology and what it means.
One of the more common terms you are likely to run into in your search for home audio is audio channel, whether it's in reference to television, surround sound, or home theater. So, let's demystify this jargon and understand the difference between audio channels, surround sound, and how they apply to home theater systems:
What exactly is an audio channel?
Total harmonic distortion refers to distortion that isn’t necessarily caused by speakers, but rather is a result of the electrical signal being manipulated by components in the audio chain. Thus, you can minimize THD by utilizing better audio components.
When you play a musical instrument, the sound generated is based on the string’s natural resonance. The string will absorb some of the energy and some will be created in harmony, creating a complex tone.
Likewise, when you play an audio file, the sound you hear is also based on the frequency response of the speaker. The frequency response follows the laws of physics and is useful for most inputs. However, THD is caused when an input’s frequency response isn’t similar to the speakers’ frequency response. Most music we listen to is recorded digitally and thus has a flat frequency response that works well with speakers.
How does Speaker Placement Affect Audio Quality?
When you decide to install your own home theater system, you also have to consider how to position your speakers. If done incorrectly, the audio quality can be negatively affected. If done correctly, your movies and music will sound substantially better. Unfortunately, getting the positioning right is a major challenge. The good news is that with a bit of careful planning, the results you get are well worth your efforts.
The first thing to consider is whether you want to put your speakers on the floor or on the ceiling. If you go with ceiling placement, you’re much more likely to get the right results. The ideal height to place the speakers above the seating position is 1.3 times the height of the listeners' ears. Placing the speakers within this area will ensure that every member of your family hears the best possible sound quality. If you don’t want to install ceiling speakers, you can use wall-mounted speakers. For the best results, mount them just behind the viewers' ears.
As for the orientation of the speakers … if you’re using a 2.1 speaker setup, you want to place the left and right speakers on the left and right edges of the screen.
For a 5.1 setup, you would have the left and right speakers at the left and right edges of the screen and the center speaker directly below the screen.
What are the Parts of a Speaker?
No matter how large or small your home theater setup is, it’s important that you have a good understanding of the components of a stereo system. Whether you’re buying a new audio/visual receiver, speaker, media streamer, or any other device, you want to make sure you’re buying what you need for your system.
If you’re planning to expand your audio/visual system or want to add a new device in the future, understanding how audio channels and devices work together is an important step.
The key components of a stereo system include:
- Media streamer
- Media player
- Audio/Video Receiver/Amplifier
> Media Streamers
A media streamer is a digital source of entertainment that uses streaming technology to play audio and video content.
There are a variety of different media streamers available on the market, including:
- Apple TV
What are the Different Kinds of Speakers?
The best thing about home theatre today is the fact that it’s easy to set up. Thanks to modern technology, you can enjoy a rich, immersive, and exciting experience with relatively little effort.
Although there are dozens of speakers to choose from, you’ll only need to focus on four. They include the fronts, centre speaker, and surround channels. In addition, you can also use a subwoofer if you want a more powerful and deep bass.
Let’s take a closer look at each of these channels so you can determine which one you’ll need to buy. For a more in-depth look, check out this guide to home theatre speakers.
Bookshelf speakers are the most popular in home theaters and AV systems, and for good reason. Bookshelf speakers are designed to be used as the front left and right channel in a surround sound system, whether a 5.1 channel speaker setup or an 8.1 channel speaker setup. For reference, it dominates the market share compared to tower and in-wall speakers.
If you're looking for a stand-alone speaker to provide sound for your bedroom or kitchen, bookshelf speaker are the right choice for you, unless you prefer a floor standing speaker for a dedicated subwoofer.
Satellite speakers can be placed anywhere in the room including on a TV stand or entertainment center, on the wall above or below the TV, or on a standalone speaker stand. You need to position and angle satellite speakers so they can reflect sound at your listening position.
Make sure there is nothing in your satellite speaker's line of site that can create unwanted sound reflections when it is in use.
Vs. Surround Sound Speakers
In your home theater you have a choice of installing surround sound speakers or tower speakers. If you’re trying to decide between the two and don’t know where to start, this guide is for you.
Tower speakers are designed to sit on the floor and deliver the surround sound experience from the front left, right, and center of your home theater. These speakers are usually tall and slim with long wires and slender mounts that hold them up.
On the other hand, surround sound speakers are designed to be mounted on the wall behind the TV in your home theater. These speakers output sound seperately to the left, right, and center of your home theater. If you purchase a set of these speakers you will still need the tower speakers to get the surround sound experience.
When deciding which speakers to install in your home theater, the major difference is the potential to install them in areas where space is limited. If you have a large space in your home theater for your speaker installation, you will find that tower speakers are often preferable because they don’t require mounts and special hardware to mount them on the wall.
What are the Best Speakers for My Needs?
If you’re still asking yourself the question, how many speakers do I need for my home theater, then we should start from scratch to help you figure this out. There are a few questions you need to answer first before you can determine the number of speakers that fit your needs.
First, decide if you prefer a sound bar or a 5.1 channel speaker setup. In the case of a bar sound system, you’ll only need four speakers and a subwoofer. If you prefer a 5.1 setup, then you’ll need a separate subwoofer, left, right, and center front speakers, and a left and right rear speaker.
Next, decide if you want to upgrade the quality of the sound from your television or if you want your home theater system to surpass the sound quality of your television. For example, let’s say you have a 40 inch 4K UHD Mitsubishi television. The next question is whether or not you prefer a sound bar or speaker system that fits under the TV. If you prefer under-TV speakers, then you can use a smaller 5.1 system. If you prefer the sound bar, you’ll need the same number of speakers used in a 5.1 speaker setup even though you can get away with using a 5 channel soundbar.
How Many Channels?
The minimum for a decent home theater sound system is 5.1. This is because it includes surround (surround speakers), center (speaker or woofer) and bass (woofer). But the best sound systems offer 7.1, 7.2, or 9.1 channels. This means more channels of surround sound and further speaker placement options.
Channels refers to sound localization and sound quality. The more channels, the more detailed the sound and the more directional it is. For example, when you hear a helicopter flying overhead in a 5-channel sound system, you hear the sound of the helicopter and the blades whirring around.
With a 7-channel system, you’ll hear the helicopter as well but also hear the propeller rotating and the helicopter wheels colliding with the ground…and so on.
This is especially important for movie viewing and gaming since it helps localize sound in a virtual 3D space and truly transport you to the scene. The better the sound system is, the more you’ll get pulled into the action.
Type of Speaker
In audiophile terminology, the number of channels used in a movie theater or home theater is called the "channel layout". A 2.1 channel layout means there are two main channels – left and right, and one additional channel – usually the center channel (for the dialogue). A five channel layout would add front center and surround channels to the mix.
While audiophiles argue the benefits of the various channel layouts, and when you really need one or more of the additional channels, for the home theater beginner, a good rule of thumb is a 2.1 channel system as a good starter system. As you experiment with new audio components, you may decide to add to your setup.
Five channels make for a more immersive experience, allowing you to more easily hear the action coming from different directions of the screen, but they are also more complicated to set up and require more interconnecting cables.
Seven channels are the most commonly used layout, and there are many excellent 7.1 channel receivers on the market, but there is no reason to upgrade unless you really want to. The 7.1 system offers a more immersive experience and has more accurate surround reproduction if you have a full 7.1 channel speaker setup.
Ease of Setup
Apart from speakers, a home theater system also needs a receiver or pre-amp to handle the audio and video signals and power the amplifiers. The receiver also provides the necessary surround sound signal processing functions for the outputs of the media player, DVD player, and video game console or choose from an optional external pre-amplifier.
Sound bars are an excellent and affordable alternative to a full surround sound system and provide a more flexible configuration. Also, they are a great alternative for rooms that lack space for a surround sound system.
Home theater systems also need an audio-video (A/V) source, an input device to connect the source to the system, and an audio-video (A/V) display, like a TV, to play the sound and video.
Subwoofer or No Subwoofer?
The basic rule of thumb is to keep two speakers for every seat in the room. So one speaker for the front of the room and one for the back. That way you will never miss out on dialogue from any angle. Keeping a balance between the front and back speakers is key to a great home theater audio system.
A subwoofer should be used on low frequency sounds like explosions and bass-heavy music. For best results, bass frequencies should be limited to two speakers so the sound doesn’t become muddy. You can use small satellite speakers or a medium-sized subwoofer to achieve this balance.
You are not limited to the amount of speakers you can put in your home. You can play with the configuration and use as many as you want as long as the configuration works for you.
So the short answer for this question is “ if you have the budget to add a subwoofer, then you should use it. If you do not, the sound should be balanced enough without it.
What About Budget?
Before starting to think about the myriad of customization options, you have to ask yourself is it really necessary? If your goal is to simply get a better home theater audio experience, the most economical way is to upgrade to a better receiver or sound bar. That can include cleaner, purer audio, a more powerful subwoofer and a whole array of sound customizations. However, if you’re looking to retain the vehicle audio system or can’t see yourself giving up your existing speakers (and you should consider keeping them), then you have to think about how you’re going to incorporate this system into your home theater.
The quest to find the right home theater speaker system can seem dizzying, especially if you’re a beginner. Home theather speakers are designed to play back audios on a wide range of frequencies as accurately as possible. While this goal may be a bit oversimplified, the following is a list of frequency response ranges that most home theater speakers will typically cover:
Subwoofers: 20 HZ to 300+ HZ
Loudspeakers: 100 Hz to 20,000HZ
Center Channel: 100 Hz to 20,000 HZ
Rear Channel: 100 Hz to 20,000 HZ
Front Channel: 200 Hz to 20,000 HZ
The above chart provides a good picture of what kind of frequency range most home theater systems are designed to cover.
However, not everyone’s home theater room can accommodate all of these different sized speakers. It may be that you only have room for small front speakers, or if you’re looking to add a subwoofer, you may want to purchase a separate one.
The best performing home theater system should always include at least one subwoofer to ensure that low frequency sounds are reproduced accurately (bass, explosions, etc.,), because they are frequently most dangerous for your ears. A high performing system will also include one or more dedicated front speakers.