The AV Receiver
The surround sound receiver is an important piece of equipment that is more commonly referred to as the AV receiver. AV in this particular instance refers to audio and video. In other words, the receiver receives all this information and then plays traffic cop directing it where it should go. If you purchase an all in one sort of AV receiver you will notice that in addition to conducting traffic this particular tool wears many hats when it comes to effectively running your home theater or surround sound system.
The receiver functions in the capacity of a switch for all audio and visual information that comes into your home theater system. This device takes all the source information and data and literally switches (or translates if you will) that data into pictures and sound. Without something to operate in this capacity it would be impossible to have a home theater system as the information couldn't be properly filtered and translated into the areas in which it needs to go.
Surround decoding is yet another task that the AV receiver performs with grace. Surround sound is encoded onto the discs that we play in our theater or sound equipment. The most common type of encoding is designed for 5.1 channel surround sound systems such as Dolby Digital or DTS receivers. There are others that exist but the vast majority of DVDs are designed and encoded for the above mentioned 5.1 channel systems.
As if these weren't enough the AV receiver also works in the capacity of a signal processor. Common signals that are processed by the receiver are the following: THX post-processing, bass management, digital audio decoding, and simulated soundfields. If at all possible and budget friendly to do so you should really take the effort to find an AV receiver that is THX certified. The requirements to meet the minimal certification standards make a system that meets those standards an excellent investment for your home theater or surround sound needs.
Amplification is yet another of the many tasks performed regularly by your AV receiver. This is an important task to your surround sound and the overall 'theatrical' experience of viewing movies on your home theater. You will probably be wise to check with your retailer about how much amplification you actually need in your home theater, as there are many mitigating factors that affect that number. Among some of the mitigating factors are: ceiling height, square footage of the room, flooring material and other things as well). While more power is good in most situations there are times when it is simply too much for your system to handle. This is one reason that many people opt to buy ready-made box kits for their surround sound and home theater needs.
Last but certainly not least, the AV receiver actually works as a tuner for AM/FM radio. Don't be too shocked and awed by all the jobs that this one little device does, just remember this when you see the sticker price and think to yourself how much more you would pay if you were buying a separate device for each of these functions. We should all be grateful to the person who invented this particular contraption and be glad to pay the price we are paying for the amazing sound that is produced.