Home Toys Article
- June 2005 -
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If your budget allows, you can used advanced construction techniques to keep your theater soundtrack from annoying the rest of your house, your neighbors, and scaring the neighborhood pets. In addition you can keep outside noises from intruding into your theater.
by Steve Faber, www.1touchmovie.com
So you've finally made the decision, you want a home theater. There are many questions to answer before you even begin to swing a hammer. The key to maximizing your enjoyment is careful design. Many disciplines comprise media room design.
Interior design, architecture, acoustics, electronic systems design, electrical engineering, control systems design and video systems design all come into play when designing a home theater. These days, computer and network expertise is increasingly necessary too.
Obviously, knowing the intended use of the facility is paramount. A media room that is going to be used primarily for a group of guys to watch sports on weekends is going to have some very different requirements than a dedicated theater used mainly for a couple to watch movies. It is important to know as much about this as possible. Sometimes the client will come out and tell you. Other times, you have to ask careful questions to get the best picture of how the room will be used. If it is a personal project, you obviously have a much better idea. Keep in mind that once the room is complete, you may use it differently than originally intended.
You first need to thoroughly examine your needs. How will the space be used? Is it to be a true dedicated theater or a multi use room? How many people does it need to accommodate? Will you use the theater for only movies or will you watch other programming such as sports and TV shows as well? Will it be used by kids, adults or both? Will it be a gaming facility? Will it be part of a whole house audio / video system or a stand alone home theater? Do you want to incorporate elements of your home's existing décor into your theater or do something completely different? What type of movies do you enjoy watching; action/adventure/bang-bang, comedy, dramas, or some mixture? Do you have any ideas on what you would like your theater to look and or function like or are you pretty much undecided?
Then look at your resources; space, expertise, finances, existing equipment. Do you have equipment you will be incorporating into your new home theater or are you buying mostly new gear? Does it need to fit into an existing room or are you lucky enough to be building a room just for your home theater? What is your budget? Are you working with a professional designer and/or installer or would you like to? If you are remodeling an existing space, what type of construction is the residence? What is the proximity of adjoining living spaces, if any? Is this your first theater, or have you had the pleasure of one or more in the past? Do you want dedicated theater seating or couches & loveseats?
You can see there are many things to be taken into account when conceiving your home theater project. If you are doing a true, dedicated theater you will be able to accomplish some things that are very difficult to achieve when you are dealing with a mixed use facility because you have to make fewer compromises.
Once you've answered the basic need questions, you can begin the design process. Let's look at a true, dedicated theater, one that you can begin completely from the ground up, without having to fit into a pre-existing space.
First of all you must determine how many friends and family you'll have over for movies. If your room must serve 16, obviously it will have different requirements than for a theater seating only four. From this determination, you can start the process of determining the size and shape of your theater.
If you have an overall space to work with, you can begin to make a general seating plan. The exact locations will come later, dictated by room acoustics. If you are using dedicated theater chairs, you must determine how many to place per row and how many rows you require to accommodate your guests. Theater chairs come in a huge variety of styles, colors and fabrics. You must select the correct ones to go with your desired décor. If you are working with an interior designer, they will be quick to select chairs that work with the aesthetic they are trying to create.
You need to see what chairs you are using to determine their width. From that, you can then figure the space required for a row of seating. This procedure is different if you are starting with an existing space and one or more predefined dimensions. In that case, you would start with the width and figure how many chairs you could fit in the space. In some cases, you may have to revise the number of guests you will be able to seat.
Once you have determined the space required for a row of seating, you can see how many seats you can fit into a row and how many rows you will require to accommodate the desired number of theater guests. You should figure about 18" - 30" inches from the back of one row to the front of another, depending upon the type of chair you are using. It is a great idea to use tiered seating to give good sightlines to the screen. Put each row that is behind the front row on a riser to allow an unobstructed view of the screen. Typically, an 8" riser works well.
Screen size is usually derived from the seating distance. Once your seating is laid out, you can determine the screen size. The number of seats, acoustic concerns, and room size will determine the distance from the seats to the screen. The distance to the primary seating location, known in the industry as the "money seat", will determine the optimum screen size.
The screen should occupy a viewing cone that extends 15 degrees to either side of center, for a total of 30 deg. A basic rule of thumb dictates a screen width of 1/2 to 1/3 the distance from the primary seat to the screen. For example a distance of 14' (168") would support a 45" x 80" screen very well. Keep in mind this a general rule and there are many exceptions. Too large a screen will lead to fatigue from constant eye movement. This phenomenon is often unnoticed at first because it can be very subtle. Too small a screen detracts from the theater experience by reducing the impact and amount of information conveyed to the viewer.
One of the basics for a great home theater is proper acoustics. Room acoustics is dictated in large measure by the size and shape of the room. If you have a dedicated room, especially if you are building a new space, designing for proper acoustics is much easier. One of the most common acoustical problems is known as standing waves. They are caused by the interaction of sound waves inside the room with the room itself. Standing waves are a function of the relation of a wavelength corresponding to a particular frequency with the dimension of the room in one or more axes.
In more basic, oversimplified terms - all sounds are waves and all waves have a wavelength (even the ones in the ocean). The wavelength is determined by the frequency of the sound and its speed. The speed of sound, for our purposes, is a constant. The frequency is what determines the tone or pitch of the note. If the wavelength of a particular note happens to be the same, or an even fraction (1/2, 1/3, ¼, etc.) as one of the room's dimensions, there'll be a standing wave created. Standing waves cause certain frequencies to be accentuated at various locations in the room and reduced in others. Basically it can cause one seat in the room have great sound and another to have very poor sound.
In order to reduce the effects of standing waves, it is best to have the room follow certain dimensional ratios. (ratios of HxWxL). First of all, run & hide from a room that is a perfect cube. You should avoid rooms with any ratios that are perfect multiples of each other. An example of a poor room would be a 15' x 20' room with a 10' ceiling. Some good ratios are 1 x 1.3 x 1.7 or 1 x 1.3 x 1.9 or .9 x 1.3 x 1.6. It is easier to work with a rectangular room because the good speaker and seating locations are easier to predict.
These basic rules can help determine the suitability of a room or enable you to construct one that works well for your home theater. Later we'll examine how to use these rules to place seating and speakers.
If your budget allows, you can used advanced construction techniques to keep your theater soundtrack from annoying the rest of your house, your neighbors, and scaring the neighborhood pets. In addition you can keep outside noises from intruding into your theater. Keeping the noise floor low will enhance the experience and keep you from having to turn up the volume so loud. In turn, lower absolute volume levels enable you to use less amplifier power and speakers with lower output capabilities, saving money on equipment.
At this point, you should be able to determine the size and shape of the room, the general seating layout, the screen size and distance to the screen. Next time we'll look at: room construction techniques; how to place the seats; what to use for a display and, if applicable, where to put the projector and other equipment. Later, we'll look at interior room acoustics, equipment selection, lighting control and automation.