Audio & Video Specification

This design for your home cinema or Media Room must be carefully considered with a huge amount of attention going into the design process and equipment selection.

There are clear performance objectives for both audio and video. Home cinema design is not a subjective engineering process, it must be clearly defined by many standards, documents, and codes of practice.

All home cinema designs require a careful mix of science & art. Every room has issues that need to be dealt with at the design stage, and the best rooms are always those that have had the best application of intelligent compromises applied.

We are often requested to create several designs of the same room, with different equipment, configuration, and performance objectives, before finalising on one design. This is not unusual and it is this process that really adds value to the end result.

We aim to meet performance objectives set out to 105db reference level at the listening position for the audio system, as well as a minimum of 30 ftL for the front projection system in relation to the video image. It is also important to mention that the noise floor of the room itself is important to increase the perception of the dynamic range of the audio. The video also requires careful control of both natural and artificial light to increase the perception dynamic range of the video image.

Cinema and Media Rooms also need to be well ventilated and comfortable places to spend your time as well as the requirement for a simple control interface that will allow you to enjoy the movie or game with the minimum of fuss.

Surround Sound

For many people, a Surround Sound system is the traditional 5.1 setup, consisting of 3 front speakers for the left, centre, and right channels, 2 side speakers used for the surround channels, and 1 subwoofer for the low-level frequencies. This basic level of Surround Sound is designed for small to medium-sized rooms, and only considers a sing “sweet spot”. But what if the room is larger? 7.1 adds 2 extra rear speakers, which spreads the surround effect over a larger area, but this still only considers a single sweet spot.

So, what if we want more than one sweet spot in the room? In reality, the central area will always be the best position, but we can expand the area to cover multiple speaker positions by considering the placement of the speakers. This could mean having extra side speakers so that each row of seats has a dedicated side channel, adding extra front left and right speakers to expand the width of the sound space, and likewise with the rear channels. This is why larger cinema rooms expand the number of speakers beyond the more common 5.1 and 7.1 systems. They are not adding additional sound content or volume, but rather spreading the sound more evenly throughout the room.

So far, we have considered the speakers, but what about subwoofers? The number of subwoofers is represented by the second number in the 5.1/7.1 notation. Whilst off-the-shelf systems usually only include 1 subwoofer, it is far better to use a minimum of 2. This is not to add additional bass, we tend to turn down the subs more when using multiples. The purpose is to manipulate the acoustics of the room to provide better definition to the low-level frequencies. For a 2-subwoofer system, you would ideally position one sub at the front centre of the room, and one directly opposite at the rear of the room. As we add more subwoofers, we tend to stick to even numbers and keep to this parallel arrangement. Many poorly balanced Surround Sound systems have very loud bass, and this happens because with a single subwoofer at low volume, it is difficult to discern bass. With 2 or more subwoofers, we can improve definition without the need to make the bass overwhelming.

Dolby Atmos

The traditional Surround Sound system has been expanded to add overhead speakers to provide a more 3D sense of surround sound. This expands the usual notation for 5.1 to 5.1.2, just like its precursor 5.1.2 is designed for small to medium-sized rooms, for larger rooms we can expand to 7.1.2 or 7.1.4. We can also expand this 3D surround sound to cover a larger sweet spot using the same speaker placement techniques as before.

Dolby Vs. THX

Dobly are inventors of audio decoding and listening formats used by the film industry when mixing and mastering Surround Sound systems. Dobly publishes guidelines for the placement of speakers so that the system can accurately reproduce sound mastered by the film industry. Dolby's guidelines cover the traditional Surround Sound layouts, including; 5.1, 5.1.2, 5.1.4, 7.1, 7.1.2, 7.1.4. Dolby has limited guidelines for larger systems for domestic home use.

THX offers more guidance for home cinema. THX stands for the Tom Holman eXperiment, the company THX, founded by George Lucas, took Holman’s experiments into how sound is perceived by listeners in rooms, and applied it to cinema. Holman’s experiments found that spreading the speakers slightly further apart allowed for a better listening experience, but for smaller systems the THX speaker placements are very close to the Dolby guidelines, as the cinema gets larger, THX offers a simpler design principle with better user experience. Additionally, THX offers certification for products that reproduce sound to the highest standards of user experience, they also include an audio format for THX Advanced Speaker Array (THX ASA) which is particularly useful for larger cinemas where we need to spread the sound evenly.

One of the most important decisions you can make about your new home cinema is the aspect ratio for the projector screen: Widescreen or Ultra Widescreen / Cinemascope.

The aspect ratio, is the ratio of the width of the screen to the height of the screen, providing the viewing area. The most popular aspect ratio for consumer video display is 16:9, which is the standard TV format. The numbers mean that the picture is 16 units wide for every 9 units in height.

Screen Size - Widescreen vs Ultra Widescreen

If you are going to use a flatscreen TV for your home cinema, you are restricted to the Widescreen (16:9) format. But if you are planning to use a projector and screen, you have a couple of other options, the most common of which is 2.35:1, widely known as the Cinemascope format. This is a wider format than standard 16:9. Many people prefer it because it matches the aspect ratio of a lot of movies being produced today.

Videos and movies are made in a variety of different aspect ratios. There is no standard. So no matter what aspect ratio your screen is, you will always end up with black bars at the top and bottom of some material, and black pillars at the sides of other material. The only time you don't get black bars is if you are viewing video or film shot in the format of the screen you are using - either a film prodcued in Widescreen displayed on a 16:9 screen, or a movie shot in 2.35 on a 2.35 Cinemascope screen. In both of those cases, the screen frame will match the picture precisely, and no black bars will exist.

In the main, Widescreen is best for TV broadcast, and Ultra Widescreen / Cinemascope is best for movies, but not all modern films are produced in the Ultra Widescreen format. A few, including some new and popular titles, are produced in 16:9. 

Which of these options is the better choice depends on what you watch most frequently. If you watch a lot of TV broadcast content, you will probably want to see it full frame. If you don't watch much TV, and your primary objective is seeing movies in full frame without edge compromises, then the Ulrtra Widescreen format screen is the better choice.

The ultimate decision should be based on the type of material you prefer to watch...what kind of content do you care about most in your cinema? If your interests are primarily in movies, the Ultra Wide format is an excellent choice. If you add HD sports broadcasts and music concerts to your viewing mix, you will usually get a more immersive experience with a Widescreen format.

One reason people like the Ultra Widescreen format is that it can have a more dramatic appearance compared to standard Widescreen. If a standard Widescreen picture is being displayed, and you switch to an Ultra Wide image, it looks even bigger and more impressive. This switch is done either with movement of the projector's zoom lens or the deployment of an external anamorphic lens (a more costly but superior alternative). Whichever way it is done, there is a certain WOW factor, and many people find that it adds excitement to the home cinema experience.

If you are looking to achieve the best of both worlds, and want to use your Home Cinema for broadcast TV content as well as movies, then the ultimate solution is to use a masking projector screen. With a masking screen, we are able to adjust the viewing area of the projector screen, depending on what content you are watching.