What is Home Audio?
Home Audio isn't what it used to be
In case you haven't looked in the last decade or so, the world of home audio has morphed into a new animal called Home Theater. While the topic of home theater typically includes display devices, the real definition of a home theater system is any display device accompanied by some form of multi-channel surround sound system. When looking for a full-sized home audio system at any retailer you're effectively looking for Home Theater. The availability of low cost processors, integrated circuit and stiff competition for good quality means there has never been a better time to be in the market for a Home Theater system.
So, what's required to turn my TV set into the center of a Home Theater system? Today the TV must be accompanied by a Dolby Digital audio system, at the very least, to be considered true Home Theater. Dolby Digital is an audio process that involves a total of six speakers. Also called 5.1 surround, this includes five speakers capable of a full range of sound and one subwoofer that will only carry the bass or Low Frequency Effects (LFE). The sub is responsible for 1/10th the range of your full speakers, so it gets designated as the .1 in a 5.1 system.
AC3 is an old name for Dolby Digital but it still means the same thing. Dolby Surround and Dolby Pro-Logic are older standards of surround sound. Older surround methods like Pro-Logic can still be the center of a Home Theater system, but you won't find receivers whose main multi-channel processing is based on Pro-Logic anymore. Today Dolby Pro-Logic II provides a variety of processing effects for two-channel material. It is a great way to add depth to CD recordings, stereo television shows or anything that has a two channel audio signal.
There are other processing standards as well. DTS is another Home Theater surround process that is very good at high resolution surround mixes and many DVD movies have an alternate DTS mix. DTS ES and Dolby Digital EX are extended surround processes that add two back speakers to the existing surround speakers. But the two back channels are not discreet and are certainly not required for Home Theater.
The speaker layout of the Dolby Digital system requires three speakers at the front of the room with the center above or below the TV. All three front speakers are aimed toward the viewing audience. These speakers are designated as the front left, front right and center speakers. Front left and right speakers and their accompanying channels of sound are familiar to anyone who's ever used two-channel stereo. These are your left and right speakers that will be used when you perform any stereo playback through your Home Theater system.
Behind and to the sides of the audience should be two surround channels aimed toward each other and at the sides of the audience. These will carry rear left and right channel sounds, giving depth and surround effects to the presentation. The subwoofer can be placed pretty much anywhere in the room because we humans have difficulty localizing low frequency effects. Low frequencies emanate in all directions from the speaker so they're not required to be aimed at the audience. The most popular configuration for the sub is to corner load or place it in the front corner of the room. Corner loading the sub augments the deep bass sounds and causes interaction with the walls around it, forcing certain low sound to reverberate through the room with a little more volume.
Once these elements are in place, you have a legitimate Home Theater system. Your budget and available space are important considerations when building your Home Theater system- you'll need to tailor your choices accordingly. Every electronic component you choose must be compatible with the others. Often this is simplified by an all in one kit that allows the manufacturer to build a complete system for you. Complete systems are great for guaranteed component matching and speaker timbre matching. However, it can be pricey to buy everything at once and it makes no use of some parts you may already have.
Home Theater In A Box (HTIB) is a low cost alternative to buying separate components. The bad news with HTIB is that they simply don't sound as good as a component system. There are some decent HTIB systems out there and names like Onkyo have taken HTIB to a whole new level of quality sound. But in general, you're better off piecing together your system one component at a time than taking the easy way out with HTIB.
If you don't care about surround processing at all, a receiver with two speakers is an option that many Home Theater receivers tailor themselves to easily. Since most manufacturers came out during the two channel stereo era, many have created Home Theater receivers that specialize in two channel musical playback. Look for brands like Arcam's Diva line, Yamaha and Pioneer Elite. These two channel mode receivers have alternate two channel amps that kick in when you switch over to stereo mode and disable the multi-channel features. The two channel mode on these specialty receivers will have more power and greater access to the system's power supply to draw more current.