15/04/2010 How do you design a Home Theatre for a limited space?

Tagged under Home Theatre
Posted by Len | No Comments

This article has also appeared in the April edition of T3 magazine:

The concept of a Home Theatre holds great appeal for most of us. The ability to simply put on a good movie, turn down the lights and be transported away to wherever that movie takes us is a luxury, particularly when it does not mean leaving the house. The drawback is that a Home Cinema needs space, and with an increasing number of people either downsizing or moving into inner city residences, space can sometimes be at a premium.

So how do you fit a quality Home Cinema into a small area?

The good news is that technology is on your side. Panel TV’s take up much less space than the older style CRT’s, and are very much at home hanging on the wall. If you decide to go down the projection route, they have also shrunk dramatically in size over the last decade. The performance of small speakers has also improved, as have in-wall and in-ceiling alternatives.

The best starting point for any cinema (be it large or small) is to sort the seating arrangements. The viewing position should be half to two thirds back in the room. If you sit back on the rear wall you will experience issues with room acoustics, plus it is almost impossible to correctly situate the rear speakers where they will give you a good sense of surround. Once you have positioned your seating position you can then calculate the size of the screen that will best fit this area. The most common mistake people make is to purchase the largest screen they can fit into the available space.
There are a number of different methods to calculate screen size, and even then your own viewing habits need to be taken into consideration. When you go to the movies do you like to sit down the front, or are you a rear row person. We all have our personal preferences. The recent advent of High Definition formats and TV’s also means that you can sit closer to the screen without noticing scan lines, video artifacts, etc.

However, if you are going to do it by the book, and we suggest that this is a pretty good place to start, the Society of Motion Pictures and Television Engineers (SMPTE) recommend that the left and right edges of the screen should be no more than 30 degrees off your viewing access. This equates to the distance between your seating position and the screen being 1.9 times the width of the screen itself (do not confuse this with the screen size, which is measured diagonally). So, once you have your seating position measure the distance between it and the screen, divide that by two, and you will be close enough to the width of screen best suited to your room.

Then work out where you are going to house the necessary electronics in the room. It is going to be necessary to house at least two pieces of electronics, and more in most instances. In most cases this will be in a cabinet or shelving system situated under the screen. There are two advantages in this solution, it will give you a shelf that you can sit the screen on, as an alternative to mounting it on the wall, and secondly you will only require short cable runs from the equipment to the screen. The other option is to house the equipment on the side wall, which makes access so much more convenient, but you will need to allow for cables runs from here to the screen. Don’t forget that it is also necessary to get power to the screen.
A good suggestion is that the wall behind the screen be painted a dark or subdued color. Firstly the screen will not dominate the room as much when it is not in use, and secondly if you have chosen light or bright colors for the wall it can detract from the screen image when in use.

Once you have the screen sorted it is time to look at the audio side of the system. There is no doubt that the importance of the audio system is greatly underestimated in most domestic theatres. Film director George Lucas once commented that a great movie experience is made up of 50% vision and 50% sound. Numerous studies have indicated that a small screen with a great sound system will give more enjoyment than a large screen with a poor quality sound system.
The options for the audio side of the system are numerous and varied, and the final solution will be dictated by the ability to run speaker cables, the size of the environment (is it small, or is it really small), and budget.

Budget first. Home-Theatre-in-a-Box is a recent phenomenon in the A/V industry. This is a complete surround sound system comprising of speakers, receiver and DVD or Blu-ray player supplied in a single carton. Its rise to dominance has been due to two reasons. Firstly price, and secondly the fact that the major electronics manufacturers realise that most of their products are sold through the major department and box-moving stores, where the technical expertise of the staff is at times lacking. It is an easy product to sell, without the need for a lot of knowledge. The downside in the majority of cases is performance. The upside is value for money. However unless budget dictates that you invest in a HTIAB, investing in a separate A/V receiver, DVD or Blu-ray player and quality speakers will yield far better results.

If the installation of speakers cables is out of the question, and/or the room is particularly small, you could consider using a ‘Sound Bar’ instead of multiple speakers. While these have been around for some time, it is only recently that they have become popular.
A Sound Bar is a component that sits below your screen which houses a number of speakers, the required amplification and processing, plus the inputs necessary for external sources such as Tivo, Foxtel or Blu-ray. One of the original and best exponents of this technology is Yamaha. Their YSP-4100 for example houses 42 speakers and 42 digital amplifiers. It boasts 4 x HDMI inputs, and includes an FM tuner and iPod docking facility. It is capable of decoding all of the major surround formats, and all of this is housed in a box measuring 1030mm wide, 212mm high and 90mm deep. It will sit neatly and relatively unobtrusibly under any flat screen plasma or LCD TV.
Sound bars work though a combination of utilising the reflective surfaces in your room and some very cleaver psychoacoustics. The effect can be unnerving – despite the fact that you are well aware that all of the sound is emanating from the box in front of you, the sensation of hearing information from behind you is uncanny.

If on the other hand if there are no issues with running speaker cables and the area is large enough, the best effect is still going to be from using a conventional speaker combination. This consists of two speakers which will sit either side of the screen, a center channel speaker which sits directly below the screen, plus two rear channel speakers, which are positioned either beside or behind your seating position. The final speaker is the subwoofer which will sit on the floor. This combination is called a 5.1 speaker system, and is sufficient for most small environments (a popular alternative is a 7.1 array which has surround speakers both beside and behind your seating position, and is better suited to larger environments.)

There are a number of rules that should be adhered to when choosing and positioning speakers in your room.
• Do not underestimate the importance of the centre speaker. Almost all of the onscreen information is channeled to this speaker, and at times as much as 85% of the soundtrack is coming from this speaker.
• It is imperative that the center speaker sonically matches the main (left and right) speakers. Otherwise as the action moves from left to right or vice-versa the character of the sound will change as it passes through the center speaker.
• Do not position the left and right speakers next to the side walls. This will cause unnecessary reflections.
• The three front speakers should be positioned as close to ear height when you are in the listening position.
• The rear speakers should be approximately 400mm above ear height when you are in the seated position.
• Sub-woofer placement can be tricky. Firstly ensure that it is not in the corner of the room – it will tend to boom. Because of the length of the sine wave of a bass note, bass can form peaks and troughs in a room, and the smaller the room the worse this problem can be. This means that as you walk around the room you will find some areas where the bass is exaggerated and others where it almost disappears. It is important that you have a flat response at your seating position, and to achieve this you may have to experiment with the sub positioning, something that is not easy in a confined space.
While there can be no disputing that free standing speakers will offer the best performance in any environment, there is one compromise which you may consider for a small space, and that is using in-wall or/and in-ceiling speakers. The performance of both in-wall and in-ceiling speakers has improved immensely over the last decade, and many companies are now producing examples of these specifically for theatre applications. They are ideal for confined areas as they take up no space at all, and can be painted over so that they virtually disappear into the wall or ceiling.

However, a word of advice. If it is your ambition to build a theatre with a high level of sound performance don’t succumb to the temptation of placing your front speakers in the ceiling. Watching the actors lips move on the screen but hearing the voice coming from the ceiling can be very disconcerting. Even moving the centre speaker down to the screen level and leaving the left and right speakers in the ceiling can be very off-putting as the action moves from one side of the room to the other. Keep the relationship between the screen and the front speakers as close knit as possible.

There is some very good news on the electronics front. There are many companies now manufacturing one-box Home Theatre solutions, which frees up a lot of space. Products such as the NAD Visio5 and the Arcam Solo Movie house a DVD player, a tuner, the amplification and the processing all in a single chassis, without compromising performance. This means that all you now need to find additional space for is your Foxtel or Tivo box, if you intend to have one. The other good news is that in a smaller environment it is not necessary to aim for electronics which have tons of power. You will be better served by a lower powered, but higher quality amplifier rather than one where all of the money has gone into the wattage rather than the performance.

A good Home Theatre can be a very enjoyable addition to your home. Don’t be put off by lack of space, you will be amazed at what can be achieved in a limited environment – it just needs a little bit of planning and the right products. The results can be spectacular.

Len Wallis.

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