Building a Dedicated Home Theatre

This article describes about building a dedicated home theatre room with fully geared equipments to match with, ultimately giving you an immersive and spectacular visual/audio experience.These informations are gathered from various AV forums, home theatre consultants etc. I would like to get comments from reader if I had mentioned anything wrong. So, lets start...

A dedicated home theatre room can be divided into different sections as below..
 

A dedicated home theatre room



1. Basically, a dedicated home theatre room.
2. A display screen & Gadget for immersive visual experience
3. Supported by a powerful Audio equipment to create those shakes & impact
4. And, Sound treatment i.e. treating the sound to not to get outside from the home theatre room
   and similarly no other sound coming from outside to inside the home theatre room creating
   disturbances.

The above sections are elaborated in detail as we read through this article.

1) Home Theatre Room
      A dedicated HTR (from here on, I will be mentioning as HTR for Home Theatre Room) can be your existing living hall, bedroom or a separate room exclusively to view movies or listen to music. I would prefer a separate room for one to enjoy the maximum while seeing a movie or listening to music. This not only gives you more involvement while it also isolate the sound from reaching to your neighbours.

     The HTR has some thumb rules before finalising the dimensions. There are some golden ratios in achieving the HTR dimension while planning.

These are a few golden ratios
Room 1 - 1x, 1.14x, 1.39x
Room 2 - 1x, 1.28x, 1.54x
Room 3 - 1x, 1.60x, 2.33x

where '1' denotes the height of the room. There is no hard & fast rules that one should stick to these ratios, but it gives an approximate measurement while designing the HTR. For eg. lets say the height of the room is 8.5ft so to determine the width & length it should be calculated as follows.

8.5 (H) : 8.5 x 1.6 (W) : 8.5 x 2.33 (L) which results in 8.5ft (H) x 13.6ft (W) x 19.80ft (L)

NB: The above value are the final room dimensions after the completion of the acoustic treament. In other words, your actual room would be actually 14.6 ft wide and 20ft long, after the completion of adding the acoustic panelling etc the there would be a slight reduction in dimensions which has to match approximately to the golden ratio. There can be + or - 5% deviation from these golden ratios in that case is tolerable. But, the sad news is many could not comply with these golden ratio in their existing setups since mostly the matching doesn't happen. Either, one need to redesign the civil which is a difficult task or to extend/merge two rooms to achieve this ratio. Both is not practically possible unless one is building a new room from scratch keeping in mind these ratios.

More to discuss in detail about the acoustic treatment methods that is adopted in these dedicated HTR setups as explained in section (4).

2) The Display Screen
       Display can be categorised into two parts

1. Less than 50 inch diagonal screen
2. More than 50 inch diagonal screen      

Display can be right from a 21inch TV to 150inch massive projector screen. For a dedicated HTR setup I prefer the latter. Choosing the display depends on infrastructure, space and lighting conditions. Normally, everyone wants a big screen no matter what size the room is. Therefore, in this article I have described doing a projector screen of size say 130 inch or more. Lets see how much we can achieve with regard to our room size and other factors.

So, how to determine the screen size with the room size is the big question. I have seen in a movie theatre, while I choose a seat that is positioned little back (not the last row) and is in the centre to the screen. Others, may choose the front row or the last row or some, the corner seats. So, its ones individual preference he/she has to decide how big the screen should be. But, again there is no shortage for thumb rules for everything. 

The size of the screen is best found by dividing the room's length by 4.5. I've used 4.5 as it a 'round' number, but the actual number you use can be anything between 3.68 and 5.18 and where '4.5' is somewhere in the middle of that, but closer to the long end of the range. Dividing the room's length by the chosen number gives you an ideal screen height for that room that allows you to work out both Seating Distances and Throw Ratio (will be discussed in detail as we read through).

Eg: For Room length of 19.80ft / 4.5 = Screen height of 4.4ft, here the width of the screen can be easily determined reverse calculating the aspect ratio (this is discussed in detail as we read through).

I would like to mention here that there are a few jargon words that keeps appearing as we read through this. One need not be confused about these because it is not going to stop one making an HTR but it gives an insight about what is all about, atleast for the sake of academic interest.

Since, I have decided to choose a 130 inch display screen or more, it is practically impossible to buy that large Plasma or LCD which should cost you a fortune keeping in mind selling your house/property etc. There comes the Projector for the rescue to serve screens ranging from 40 inch to maximum 300 inch screens with a budget easily reachable.

Fig.1

All nice talking about large screens, but one has to do the math to see what screen size is suitable for the HTR. For that, I need to put you through some technical jargons at this point of time which should make you understand the logic behind why it is done, how it is done and you can visually see the end result right from the start. So, lets start from Throw Ratio (hereon I will be mentioning as TR). TR is the distance from the tip of the projector's lens to the screen (see Fig.1). Most commonly, the projectors have a TR of 2.0. Meaning, for each foot of image width the projector has to be 2 feet away from the screen i.e 2 / 1ft = 2.0. Eg, To achieve a 5 feet width image the projector has to be 5ft x 2 = 10ft away from the screen. So, using TR one can determine the throw distance or image width.

Now, here come another technical jargon Aspect Ratio (hereon i will be mentioning as AR) which is an important jargon to determine the screen size. AR is commonly categorised as below.





Fig.2


1. 1.33:1 (4:3 - Standard television)
2. 1.78:1 (16:9 - widescreen as seen in Plasma/LCD)
3. 2.35:1 (21:9 - superwide or cinemascope as seen in commercial theatre)

As you see, the image gets wider as you increase the numbers. What actually these numbers denotes? Well, it is the ratio of the width vs height. In other words, our 21 inch CRT TV is 4:3 ratio i.e. 4 divided by 3 gives you 1.33. So, the image is 1.33 times wider than height. Similarly, you see more and more Plasma/LCD TVs becoming cheaper day by day and affordable to everyone. These Plasma/LCD are all 16:9 AR i.e 16 divided by 9 gives you 1.78:1. When you go to a movie theatre, more than 90% of the movies screened are in superwide AR or Cinemascope which is 21 divided by 9 gives you 2.35:1 AR. 

Fig.3

  Commercial film makers choose the aspect ratio of the film based on the visual required for the story. Will you enjoy if the movie Transformers had been shot in 1.33:1 AR (see in the Fig.2). Since the film has visual effects it requires a much more wider spectrum to showcase it to the audience, hence 2.35:1 AR is chosen. Same goes with all movies that is being made today. A superwide or Cinemascope makes the audience immersed to the visual treat showcased in the movie. Now, see Fig.3 which shows how the actual movie which is shot in 16:9 appears in a normal television (4:3) and in a widescreen Plasma/LCD (16:9) TV. You can see black bars on the top and bottom of the screen appearing as seen in Fig.3 in a standard tv on the left, whereas the image fills perfectly to 16:9 Plasma/LCD on the right.

Why is this black bars appearing?
This is because the standard tv has to accomodate the full width of the movie so that the sides are not cropped and all detail in the movie is viewed. In doing so, the height of the movie has to be reduced thus creating black bars in the top and bottom of the screen. Similarly, when we view a 2.35:1 or Cinemascope movie on a Plasma/LCD (16:9) TV, there are still black bars appearing on the top and bottom because the 2.35:1 movie is wider than 16:9 as seen in the Fig.2.

So, hope you should have undergone some technical concepts which one should understand while building the HTR. Now, the question comes "Which type of AR should I choose?"

Before giving you an straight answer, I need to make you understand the following concepts for one to make the choice easier.

Choosing the right Aspect Ratio Screen: As you seen in Fig.2, the common AR are 4:3, 16:9 and 2.35:1 which has its own advantages/disadvantages and depends on viewers selection of movie/video that he/she is viewing. But before hand I would like you to take through the meaning of "Resolution of Video" for easier understanding of AR.

What is Resolution in a Video or TV?
Resolution in a video is the number of vertical and horizontal line present. Resolution can be categorised as 2 types a) Standard Definition b) High Definition.

a) Standard Definition (SD): Earlier, DVD movies and TV broadcast are all produced in standard definition resolution, i.e the number of vertical/horizontal lines are 728 x 576
b) High Definition (HD): Currently, most of the BluRay movies are encoded in 1080, i.e., 1920 lines horizontal by 1080 vertical lines. There is also 720 available which is still categorised under the High Definition giving resolution of 1280 x 720 lines. Meaning, the more number of horizontal/vertical lines gives amazing picture quality. Especially, you can notice in your school/business projectors, when you play a SD video on a big screen you notice square like appearing in fast moving scenes. Whereas, in HD videos there is no such pixelation because the more number of lines reduces these artifacts and gives you much clearer, sharper, stunning image quality.

Hope this gives an idea how the resolution important while viewing on big screens. Now, lets see how resolution relate to AR. The most common Aspect Ratios are explained below.

4:3 AR (1.33:1): Normally seen in a standard CRT tv, the olden days when we viewed movies on these TVs. This AR is now getting phased out and used mainly in business presentations/advertising/public displays etc.

16:9 AR (1.78:1): Since, due to emerge of HDTV (Hight Definition Television) as you seen during the days the introduction of SunDirect HD, TataSky HD, Airtel HD, Reliance HD, DishTv HD etc. More and more players are coming to market in the HDTV segment thus making the cost much more affordable during the course of time. HDTV transmission are in 16:9 AR (1.78:1 widescreen) and there is more resolution added to these signals and picture is now wider than the 4:3 AR. This AR is commonly used in DVD, Bluray, HDTV and even some movies.

21:9 AR (2.35:1): This is less common AR format to domestic segment, but common in commercial applications. As you see in a movie theatre, the picture is wider than your Plasma/LCD TV. Thats why you see black bars when viewing these movies on your Plasms/LCD TV. Now, most of the present movies are produced in 2.35:1 AR since it gives audience more immersive experience.

     Now saying all these, we the viewers need to choose what kind of AR would be suitable. Since, 4:3 AR is almost phased out and so the comparison would be between 16:9 vs 21:9 ARs.

This article below narrates the advantages/disadvantages of both the ARs and the choice of the viewer to choose which is best for him/her.

Comparison between 16:9 Vs 21:9 (Advantages & Disadvantages):
The AR is based on the viewing material that one is going to watch very often. Say, if a person is more interested in sports and would be viewing HDTV or SDTV broadcasts then 16:9 AR is the best one. Seldom, he may watch movies which are in 2.35:1 AR where black bars appear top and bottom of the screen.

Fig.4 (Cinemascope)

Fig.5 (16:9 AR with black bars on left & right sides)

Fig.6 (4:3 AR with broader black bars on left & right sides)

Say, if a person is going to view only for movies (like me) and may seldom watch TV broadcasts in that case 2.35:1 AR is the best option. A HTR often are 16:9 AR display screens balancing between both the AR formats.
What happens if a 16:9 AR is viewed on a 2.35:1 AR screen?
As you can see in Fig.4,5 & 6 the comparison how a 4:3, 16:9 and 2.35 ARs appear on a 2.35:1 AR display screen. This is same as you see in a commercial theatre.

Ok, now lets get into action...

As mentioned earlier, as we go big screen >100 inches, it is always better to go for projectors which is cheaper when compared to Plasma/LCD for that screen sizes. Say, I need to achieve 100" diagonal display screen then the cost would be approximate 10Lakhs plus based on Plasma/LCD. At the same time, a projector starts from Rs.30,000 onwards based on features, picture quality etc. There are different brands offering projectors in three different technology similar like Plasma/LCD in TVs.

Different technology in Projectors: It consists of DLP (Digital Light Processing) by Texas Instruments, LCD (Liquid Crystal Display) and LCoS (Liquid Crystal on Silicon). DLP technology is popular mainly for movie viewing just like Plasma TV where it gives theatre like feel with high Contrast Ratio. LCD are commonly used in business presentations etc where it is brighter than DLP at the same time Contrast Ratio is limited. Ok, I understand that you may ask what a Contrast Ratio (CR) means to you. CR defines the ratio between brighter areas to blacker areas i.e. 10000:1 CR means that the brightness is 10000 times more than the black area. So, more CR meaning better picture quality? not exactly, it again depends on projectors various factors like lumens, color etc. One need not require to know indepth knowledge about these ratios/factors but will be very helpful when buying a projector.
   Nowadays, LCD have improved their CR and can say they perform equally or outperform a DLP projector. It is not thumb rule that one should use only DLP projector, since many brands offers excellent features & enhancements in their respective DLP, LCD, LCoS technologies. It is upto the customer to decide which one is best for him/her depending on the budget.

Some of the few popular brands which are good in HTR setups are mentioned below for general guideline to make purchase easier.

• Benq (DLP)
• Digital Projection (DLP)
• Epson (LCD)
• Infocus (DLP)
• JVC (LCoS)
• LG (LCoS/LCD)
• Mitsubishi (DLP/LCD)
• Optoma (DLP
• Panasonic (LCD/DLP-Commercial)
• Runco (DLP)
• Sim2 (DLP)
• Sharp (LCD/DLP)
• Sony (LCoS)
• Vivitek (DLP)

Earlier, projectors had only 4:3 AR, nowdays all projectors have 16:9 AR. So, say one require a Cinemascope (2.35:1 AR) screen as seen in Fig.4 what he/she has to do to achieve the same if the projector AR is 16:9. Will the picture not have black bars on the top and bottom? Lets, learn more how it is done in the following section.

How to achieve a 2.35:1 AR from 16:9 AR projector?

Anamorphic lens

Basically, we need 3 components to make it possible
1) A projector (normally 16:9 AR)
2) Anamorphic Lens
3) 2.35:1 AR screen

Fig.7

Fig.8



Fig.9



Fig.10

See the above images for your understanding in three simple steps.  Fig.7 shows the 16:9 AR projected to a 2.35:1 screen. You can notice that a 2.35:1 image inside the 16:9 AR where you see black bars on the top, bottom, left and right sides. In Fig.8, you can see that the image now is vertically stretched using the projector's picture setting where the black bars in the top & bottom have gone and appearing only on left and right sides. But at the same time, you can notice in Fig.8 that since the image is stretched vertically it appears elongated not resulting like the original image. Finally, we place an Anamorphic lens in front of the projector as shown in Fig.9, here the lens would slide to the fron t of the projector lens using a motorised sled mechanism when viewing 2.35:1 movies. And in Fig.10 you can notice the image now expanded fitting perfectly to the 2.35:1 AR screen just like the original image in Fig.7 but eliminating the black bars completely. Thus bringing the experience as you enjoy in a commercial movie theatres.

3) Audio Setup

Fig.11 (5.1 Surround Setup)

      Audio plays a major role in HTR setup to bringing life to visual experience by creating much more feel that the audience is sitting right in the centre of the excitement. Audio department throughout these years have taken care to ensure that excitement never gets dull rather amazing as you hear more and more of the new movies released in future. This is because of the various technological research going on and implemented during the course of time. We do remember the days we were watching movies in Stereo (2 channels) in a movie theatre. But, when Dolby Laboratories introduced the Surround Sound concept thereby bringing enveloping surround sound to the audience making that he/she is sitting right in the centre of the action. This was with the introduction of 4 channels creating a psuedo surround effect from stereo source. Later on, 4 separate tracks were introduced and recorded separately thereby creating distinct reproduction of audio to the respective channels and creating more realistic surround effect. Technology didn't stop there, Dolby again introduced 5.1 channel where .1 refer to LFE (Low Frequency Effect) in otherwords called as Subwoofer to reproduce the low bass explosions/impact in a movie sound track. They called in Dolby Digital 5.1 Surround Sound as seen Fig.11. Then came the evolution of DTS firm which offers same surround sound solution as Dolby. The only difference between Dolby and DTS is both are different companies offering same technology under different brand name called "Dolby" & "DTS" with some features giving real competition between the both. Then the came the introduction of 6.1 where a centre back surround speaker is introduced between the left and right surrounds giving more depth.  



Fig.12 (7.1 Surround Setup)



Unfortunately, not many movies are produced in 6.1 Ch and rather 5.1 Ch is still common currently and even in commercial movie theatres. Now, we have a some members to the surround stable 7.1, 7.2, 9.2 and even 11.2, wherein .2 is same as .1 but adding one more Sub for more balanced reproduction of the low frequency. As of now, movies are still produced common in 5.1 and a very few titles available in 7.1. As you see there is still no .2 recordings in a sound track. It is actually the amplifier which does splitting the .1 to two separate points making it .2 for a balanced bass effect in a HTR.  In a 7.1 Surround setup, 2 new surround back channel are introduced with the existing 5.1 Ch configuration thus creating a 360 degree enveloping surround sound effect as seen in Fig.12.  Like you see advancements in Video from SD to HD, similarly both Dolby & DTS have introduced the audience to experience HD-Audio thereby giving us names like "Dolby TrueHD", "DTS-HD" giving a major leap in the audio quality reproduction. There are certain loose ends where I have skipped abruptly and only had given a brief explanation to those terminlogy which we will discuss lateron in a separate article which will be coming soon. Hope you have a basic idea of surround sound technolgy and lets move into building the audio setup

Basically, the components that makes your audio setup are

• Source: A DVD, BluRay, HD Media player or HTPC (Home Theatre Personal Computer) for playing all your discs/media. Now, more number of 3D movies are releasing hence the market is flooded with 3D BluRay players, 3D Plasma/LCD, 3D Projectors becoming popular day by day and costs drastically reducing and more affordable. There will be a separate article with regard to 3D coming soon.


• Audio/Video Receiver (AVR): An AVR is just simple as an amplifier which amplifies the signals from various sources such as DVD, BluRay players etc. It is more similar to a normal stereo amplifier which does only 2 channel amplification. Whereas, an AVR can able to decode the Dolby/DTS signals coming from DVD, BluRay players and processing to 6 or 8 separate channels. Basically, in a 5.1Ch AVR it consists of Front Left, Front Right, Centre, Left Surround, Right Surround and Subwoofer preout (denoting .1 - LFE) and in a 7.1 Ch AVR it the same as 5.1Ch with 2 extra channels for Surround back Left & Right as you see in Fig.11 & 12. In a DVD, BluRay discs the soundtrack is encoded to respective Dolby/DTS signals and these signals are then passed from the player through either HDMI, Optical/Coaxial digital inputs of the AVR. Which then decodes the signal and splits these to either 5.1 or 7.1 signals depending on the AVR and then amplifies the respective channels and feed to the speakers.
  




Satellite Speakers

 



Bookshelf Speakers

 



Floorstanding Speakers


• Speakers: Speakers play a significiant role in reproducing the sound as accurate as the original recording. I need to have a separate article to discuss indepth about speakers and you may take your time reading the same later on. The speaker has to matched with the AVRs output and impedance. Nowadays, there more than 1000plus brands offering various speaker configurations for 5.1/7.1 setups matching the AVR specifications. Speakers generally come into three forms Satellite, Bookshelf and Floor Standing. One can choose from these 3 form factors based on the HTR size and budget. Satellite speakers are generally single driver speaker units which contains one single 4inch or 5inch speaker or may have a tweeter separately to reproduce the high frequency notes. They are very compact, stylist, sleek and mostly in plastic/fibre/wood type enclosures.These are for space conscious listeners who have very limited flexibility in installtion or want their speakers to be literally invisible in their HTR. Bookshelf speakers are little larger speakers commonly in wooden enclosures and can be easily mounted in a cupboard/bookshelf where it seats perfectly to the name its called. These speakers units normally are 2 way i.e. one tweeter and one woofer or in some cases 2 way, 3 drivers where 2 mid-woofers and 1 tweeters are present. Generally, these speakers are best for listening stereo (2 channels) reproducing sufficient bass without the help of a subwoofer and clean treble (high frequency). Bookshelf can definitely improve sound quality when compared to satellite speaker units becuase of their enclosure and multiple drivers. Floorstanding speakers are tallboy units which doesn't require any mounting options as it is placed directly on the floor. These speakers are mostly 3 way with 4 or even 6 separate drivers for maximum sound quality. The 3 way driver covers the full bandwidth in a frequency where it consists of a tweeter for high frequencies, a midrange/midwoofer for producing the mid frquency like voice in a music/movie and woofer for low frequency irerespective of the separate subwoofer as we refer to .1 LFE. It is upto the user to choose the best speaker for his/her setup based on the HTR and budget.
• Cables: Cables play important role in carrying signals to the speakers without signal loss from the AVR. So, selecting good cables significiantly improves sound quality and accurate reproduction in speakers. More we will discuss in a separate article coming soon.

4) Sound Treatment for HTR

      Sound treatment plays a major role in deciding the sound quality in HTR. Even though one has got the best of players, AVR and speakers and if the room is not acoustically treated the end result will be worst. Sound treatment ensures that proper absorption/diffusion treatments are done in HTR. Normally, sound waves reflects in all sides of the room and it has to be controlled by ensuring to reach to the listeners position with very less echo/reverberation. Likewise, diffusion is a process to spread the sound waves from highly concentrated area to a lower concentrated area. In otherwords, diffusers help in spreading the sound waves uniformly in a room just creating equal effect irrespective of where we sit and listen. As for Ceiling/flooring/walls, there are sound absorbant panels available on various budget. More coming soon in a  separate article.

Conclusion

Hope this gives you an overall idea of what is a dedicated HTR and the various process involved to setup with different options available in the market. I may have abruptly skipped a topic or missed something, in that case please feel free to post your comments so that this article can be improved further in helping others.