Guide for selection, installation and placement of the components of a Home Theatre System

In a Home Theatre system, as you can see, the speaker placement is of paramount importance to achieve optimal playback. But did you know this probably already know this and also their landlord, out of the blue, you are seen to invade the living room and can not live with those parallelepipeds in the middle of the room. Place them on the wall in the corners maybe it would be better? No and again NO!

The main front speakers or must remain detached from the wall at least 50 cm and the distance that separates it must be at least 250 cm.

The center channel, almost always located on the television. Normally one uses a dual speaker broadband broadband, or two and a central tweeter. Important, do not come to mind to any place a box on your TV by way of the center channel, you magnetize the TV screen. The speakers suitable to be placed on the TV shows are shielded magnet, precisely to avoid causing problems.

The subwoofer, which is usually the most difficult component to place. To accommodate the sub, a corner of the room is fine and if you delight in carpentry work you will easily conceal the box makes it look like a piece of furniture. I must add that the subwoofer, even if your amplifier is prepared, as he told the shopkeeper, usually requires a separate amplifier.

The alternative would be a powered subwoofer. It is a box that encloses both the amplifier that the sub itself. Unfortunately the subwoofer good brand can have a considerable cost, while those cheap generally leave much to be desired both in terms of sound pressure that audio quality that, in this case, it is also important for the subwoofer.

The cases side effects or channels have the task of reproducing the effects and audio delays and in this are "helped" by both the main speakers from the center channel. Their positioning is always very critical and, unless you have programmed the arrangement of the furniture, the fateful make you sweat seven shirts. First of all, they can not stand in front of the listener, as can fit on the sides. The ideal is to arrange them in an equidistant position slightly behind the listening point and well spaced between them.

We complete this overview with the surround amplifier, after which we will see how everything will work. But before talking about amplification is a need for clarity on the standards introduced by Dolby.

With reference to Home Theatre Home Cinema renamed confine myself to a summary list that will help us understand the meaning of the symbols.

 

-       Dolby Surround was the first standard and included two front stereo channels plus rear mono channel to be allocated to at least two speakers. The audio band of the latter was limited from 100 to 7000 Hz (more or less equivalent to the yield of a television). It was a rudimentary system when compared to modern digital systems but it was the home cinema!

-       The Dolby Pro Logic is an evolved version that provides for the addition of the front center channel, in the presence of a support etched in Dolby Surround, the system is able to discern the sounds for the various channels and this thanks to the analysis of the two stereo tracks, but they are the limitations of the rear channels that are still driven in mono. This standard has not been abandoned but has evolved in Dolby Surround II allowing you to have the two rear channels in stereo.

-       The Dolby Digital Dolby AC3 is better known as the modern standard of reproduction Home Cinema. Here we count six audio channels, just 5 +1. The two rear channels are now stereo and full range, that is able to reproduce the entire audio band. To take advantage of all this technology is necessary is a compatible reader that an amplifier ready for AC3.

 

The amplifier used to drive the audio system provides, in most cases, 5 + power outputs an output of low level is intended to be sent to the subwoofer amplifier.

The 5 outputs as set out above are broken down as follows:

-       two-channel stereo for the main speakers, these channels are always working and determine the maximum power.

-       two-channel stereo or a mono system used / or drive the speakers to the rear, these are excluded and may have a lower power than the main speakers. (As seen above the piloting of the rear channels can be in mono or stereo, depending on the type of amplifier)

-       the fifth channel is always mono and manages the center speaker designed to reproduce the dialogues of movie soundtracks recorded in Dolby Surround or Dolby Digital.

-       the sixth output, as already said, is destined to the amp of the sub and almost always is low level, that provides a minimum signal intensity that can be used to be sent to the subwoofer amplifier.

-       As already mentioned, we distinguish two types of amplifiers: Dolby Pro Logic and AC3.

 

Let's work on Dolby Digital AC3. As suggested by the acronym for AC3 are digital media, in practice we are talking about DVD Digital Versatile Disc. In a DVD are placed a high definition movies, audio tracks and dialogues in different languages. All this thanks to an advanced compression technique developed by Dolby Laboratories in collaboration with Pioneer. This technique, quite simply, provides the "cut" of all that is deemed unnecessary. Needless, at least theoretically, for a normal perception based on principles psico acustic well known. To understand the validity of this technique, the best thing to do and be sensitive to. In fact, you can eliminate much of the data while maintaining a level of quality which reserves many surprises and we must not forget that DVDs have a capacity far greater than the normal audio CD.

To connect a DVD player at best, there are two possible solutions. Use the optical output digital-or six channels with RCA type connectors. In both cases, by placing the amplifier in operation AC3 and having a support etched in Dolby AC3, the signals in transit will be directed in such a way as to arrive to the various channels in the right time and to the right channel. Possible actions by the user, especially on channels effects are determined by choices made by the manufacturer of the amplifier.

 

 

The choice of the plant components

There are two types of approaches to the choice of a Home Video:

1. go to a well stocked shop and, with the assistance of a trained, to be guided in the choice of an entire system that would be compatible with the room in which it will be installed.

2. choose individual components on the basis of their knowledge, and, if necessary, make a speaker system that includes handcrafted pieces.

In both the cases, in my opinion, is crucial to modulate the plant in such a way that individual parts can be replaced easily. This means buy components with standard connectors, not in all-in-one.

 

 

Direct resources

Who does not have problems of financial resources, blessed him, will choose the best, but having to weigh the choices in order to keep spending within a preset limit it is unclear how to allocate resources.

The amplifier is the hub of the whole system, there is no doubt about this, so if we spend more than what we had budgeted, never mind. We will have a device that maybe in the future we will not regret the extra cost.

The choice of the DVD player, particularly paying attention to the connections must be made offering and the manufacturer. I think that the Asian producers, in terms of sources, not second to none.

The front speakers determine, along with the amplifier, the total power of the system to be suitable to the environment in which the system will be installed. In my opinion, systems AC3 Dolby Digital is not strictly necessary to use the subwoofer, thanks to the new standard, with a reproduction of the audio range also on the side casings. Save the expense for the subwoofer is to buy a good pair of front speakers is a great choice. I will spare you any comment on the choice of speakers, because it would be superfluous, though starting from a configuration with dual 16-17 cm woofer and tweeter seems like a good idea.

The cases side effects or channels. If we are setting up plant in AC3 is a must for a full-range speaker, the minimum would be 13-16 cm woofer and tweeter. In the case of Dolby Pro Logic is also possible to opt for the speakers limited to the range 100-8000Hz: some manufacturers have set up templates that you can hang on the walls.

 

The center channel, better choose good quality: maybe in the future we want to change some part of the system but a good center channel to be placed on the TV will keep it in the future. The solution of the dual tweeter and midbass from 10 cm center is certainly the best. "

 

 

30/06/2011

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Translated via software

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Source:

Italian version of ReteIngegneri.it