Home Theatre Audio – Five and Sevens and Subs
There was a time when audio in your home was quite easy. For your grandparents, it was probably a hi-fi. That was a huge box almost the size of a coffin, It had speakers on either side and an integrated amplifier, radio and turntable in the middle. It also made a great stand for chips and dip.
In you parents’ time, the home stereo came along. The detachable speakers were a big advance over the hi-fi, and quality was sometimes (though not always) pretty good.
Now, you’re automating your home and the time has come for you to put in a home theatre. The designer is going to talk to you about what kind of sound you want. Questions about 5.1, 7.1, Dolby, powered subs and a lot of other things are going to come up. So, what are they talking about and what do you want?
The main thing to understand is that the quality of your listening experience in a home theatre is very much a product of how many speakers you have and where they are located. That’s because there’s a different sound coming out of each speaker.
How does it do that? Well, it all starts at the DVD. It has information coded into it that has the sound separated into multiple channels. From there, the sound goes into a receiver that can make sense out of the information on the DVD. The receiver amplifies these signals and sends the sound to each speaker. The speakers are meant to positioned all around you, therefore the name Surround Sound. So why all the numbers? It’s actually pretty easy.
In the days of stereo, we could have called the system a 2.0 two different sounds, two speakers. About twenty years ago, with the arrival of the DVD, that changed. Now there was room for a lot more audio information, and we had Surround. Now instead of two channels, there was room for many more channels of audio. The next thing was to build receivers that were capable of taking the information from a DVD, breaking down the signal into its separate parts and driving it through the individual speakers.
5.1 Surround sound
The first system to come along was 5.1. Here’s what the five channels are:
A center channel. The speaker for this one is usually placed in the middle of the screen
Left and Right front channels. Placed on either side of the screen.
Left and Right surround channels. They’re placed behind you on the left and right.
The subwoofer to produce really low music, explosions, rumbling sounds. It can be placed almost anywhere in the room.
These systems really shine in small and medium sized rooms. There are many people who would find 5.1 to be a very good system that will suit their needs for a long time. But there is another option.
7.1 Surround sound
The 7.1 system does all the things a 5.1 does, but it also does another trick. Instead of combing the side and rear sound into one speaker, (like 5.1) it splits them into separate channels. Now you have speakers on either side, as well as in the front and the back. If you have a large home theatre room, you can really appreciate the extra spacious sound you get from a 7.1 system.
The 7.1 system comes with a warning you may have a 7.1 system, but you may not be listening to true 7.1 sound. Here’s why: To get 7.1 Surround sound, EVERY part of your system has to be 7.1. That means you have to have a DVD or Media Player that will produce 7.1. It means you have to have a receiver that produces 7.1. You have to have cables that are up for carrying this much audio information (very likely this will now involve HDMI cables). After all that you need to have seven speakers plus a subwoofer in place to carry the sound to the listeners.
That having been said, even without a true 7.1 system, you can still get some very nice results by putting a 5.1 signal through a 7.1 system. Have a look on your receiver. It might say that it has 7.1 DSP (Digital Signal Processing). It may have other names like Dolby Pro Logic, but the point is it takes a DVD that only has 5.1 and finds a way to split the sound so you get a separate signal through the side speakers giving you a 7.1 experience.
Now you know what is Home Theatre Audio – Five and Sevens and Subs.
What about 9.1? Or 11.1?
Like everything in technology, the envelope is always being pushed. You a going to hear about 9.1 or even 11.1 systems. Not only would you need a receiver that can handle this, you need the extra speakers. The important thing to remember is that most DVD’s only have 5.1 sound embedded in them. (with a smaller number of 6.1 and 7.1). That means that almost all systems above 5.1 are to some degree simulated. Still, a properly installed and tuned 9 or 11 speaker system can sound amazing, especially in a very large room where you have space for lots and lots of speakers.
The truth is, for the average small or medium sized home theatre, 5.1 does a very good job. For the audiophile or the family with a huge home theatre, the 7.1 can be a nice to have. The 9 and 11 speaker systems are great for early adopters and those who want to show off a little when they’re giving the tour of their system.
If you still find it hard to grasp Home Theatre Audio – Five and Sevens and Subs, make sure you talk to the home automation professionals at OneTouch AV. They will analyse your theatre space, respect your budget and make sure you get the system that suits your entertainment lifestyle. If you need any help designing your audio visual or automation systems please feel free to contact us.