Room with a view
Aug 1, 1999 12:00 PM, Sharon Christopherson
Setting up a home theater with a front-projection system can range from asimple job to a complex installation. This is a step-by-step guide to front-projection system installation to help ensure your success. Although most front-projection system installations will follow all of the steps, some simpleapplications will not. Taking the time to plan the installation up front,however, will guard against costly mistakes and miscommunications with theclient. Review your drawings and plans with the client often and get hisapproval of any changes along the way.
Determine the client's needs first. If the room will not allow certainaspects of the application the client would like, make sure he or sheunderstands that. If the client does not have a projector already,recommend one. If the room is being built, you may be able to work with thearchitect, recommending changes to ensure a quality projector installation.For example, the ceiling will need enough support for five times theprojector's weight. Have the architect include a conduit for cabling and agood screen location.
More often, you will be remodeling an existing room - one not designed as aviewing room. The goal, however, remains the same - present the audiencewith a bright, crisp image on the screen that each viewer can see clearly.
Establish the scope of the job by creating a set of scale drawings (bothplan and elevation views) of the existing or proposed room. Include sucharchitectural features as entryways, doors and windows. Be sure to make thedrawings large enough to add information as you work. The morecomprehensive the job, the more detailed your drawings will be. Forelements of the project that may may delegated to other contractors, suchas security or home automation, provide technical drawings for the keypersonnel.
Next, specify a screen. Fit the screen to the audience, which is a goodrule of thumb for specifying an appropriate screen. To determine screensize, find out what kind of image the client plans to project and how theaudience relates to the screen.
There are two types of images projected - conventional video images (videofrom VCRs, DVDs or CCTV) and digital or pixelized data (spreadsheets andelectronic presentations). If the client indicates that most of the imagesto be projected will be digital data, which is rare in residentialapplications, keep your screen-size calculations at the large end of thescale. Remember, as screen size increases, there is a point of diminishingreturns. Unless you have a tremendous amount of light and great optics,your image will lose quality beyond a certain size.
Calculate the image size required by measuring the audience viewingdistance. Use a copy of your room drawing to note the audience arrangement.Measure the distance from the screen to the viewer who is the furthest fromthe screen. For computer graphics and text projected in a 3:4 aspect ratio,most experts suggest that the screen height should equal about 1/6 of thedistance between the screen and the most distant viewer.
You should also consider the viewers who will be closest to the screen.Viewing computer images from a distance of less than two screen widthsmakes individual pixels apparent. Text will be difficult to read. Once youknow how large the projected image will be, you can figure out where toplace the screen and what type of screen is the most appropriate for theviewing conditions.
Add the screen to the plan view of your drawing. Then, determine the angleof view for the viewers seated in the outermost seats. The viewers with theworst angle of view are typically the ones sitting in the first row,farthest from center. Digital data is difficult to read at more than a 30degree angle. You can compensate by specifying a special screen surface,but do not seat audience members at an angle greater than 45 degrees.Instead, consider rearranging seating temporarily during a period ofextended viewing or moving the screen to another wall.
The screen height is measured from the floor to the bottom of the screen.It should be a minimum of 48 inches (1.2 m) above the audience floor forall commercial applications, allowing those seated toward the rear of theaudience to see the screen. Make sure that all audience members have aclear, unobstructed view of the screen. If a column, podium, fan or lightfixture blocks the view, you can move the obstruction, the viewer or thescreen to solve the problem. Place the screen so that it does not reflectambient light. You can usually control ambient light with shades. If not,specify a screen that filters reflective light or a brighter projector.
Once you know the projected image size and the screen location, you canpinpoint the projector location. For every inch of diagonal screenmeasurement, the projector will be located 1.5 inches (38.1 mm) back fromthe screen. This applies to CRT projectors with a fixed focal length, butmost new projectors have zoom lenses. The goal is to fill the screen withthe image. After calculating how far from the screen the projector must bemounted to achieve the desired image size, use your scale drawing to helpyou position the projector. Include ceiling structures as well as suchpossible obstructions as HVAC vents and blowers and hanging light fixtures.
The type of lens on the projector will determine the throw distance (thedistance between the screen and the projector). Some projectors includezoom lenses as standard equipment. A zoom lens will provide someflexibility in mount location. You can change the image size by zoomingwhen you cannot mount the projector at what you had initially believed tobe the increments. You can also cut them in half to achieve an adjustmentrange of 12 inches to 24 inches (305 mm to 610 mm). For angular orcathedral ceilings, you not only have to achieve the proper drop angle, butalso a drop of as much as 4 feet (1.2 m). Solve the problem by using acombination of angled ceiling adapter with an adjustable suspensionadapter. If the ceiling is particularly high, you may not be able toproject a perfectly rectangular image onto the screen. Some projectorsinclude a keystone adjustment to compensate for a tilted projector, or youcan adjust the amount of drop from the ceiling by adding extensions to theprojector mount. Some ceiling mounts are susceptible to vibration frommachinery and foot traffic, especially mounts that include extensions toallow increased drop. A stabilizer strut adapter adds rigidity wheninstalled between the mount and the ceiling.
For more traditional ceiling installations, use an adjustable wood-joistadapter. It can be mounted to joists between 2 inches and 7 inches (51 mmand 178 mm) wide. Simply bolt it through the beam. I-beam mounting alsorequires a special adapter. Because you cannot drill or weld to astructural I-beam, use an I-beam adapter to clamp directly to it.
Often what appears to be a custom mount may in fact be just a combinationof a mount and adapters to achieve the desired projector position. Contactthe mount manufacture if you are unsure which mount assembly you need.Manufacturers can often recommend a mount solution.
Lighting has a dramatic effect on video quality. Discuss what type oflighting the client wants. Sometimes you will be able to specify majorlighting changes. Other times, you will need to work with the existingfixtures. Whether you are working with existing artificial lighting ordesigning a new lighting system, be sure to consult an electricalconsultant if you are not a licensed electrician.
Start by adding the current lighting system into your room drawings.Include the electrical circuitry, wall switches or controls, and lamp typesand wattages if possible. Some rooms have no lighting control in the room.Unless the projection system that you are installing is capable of castingacceptable images with the lights on, you will need to add light switches.Even if an acceptable image is visible with the lights on, they may bedistracting to the viewers. If all the lights in the room are controlled byone switch, you may want to separate the circuits for different lightingbanks. Placing different banks of lights on separate switches allows rudimentary dimming. It is important that the lights immediately above the screencan be dimmed or turned off to reduce screen glare.
Determine what activities viewers will be engaged in during presentations.When installing a projector for a living room environment, be aware thatwhile the projector is in operation, other people in the room may read,write or be engaged is some other activity that requires light. Makecertain that the specified projector can produce brightness sufficient towithstand the light required for those activities. In a dedicated hometheater room, however, such lighting concerns may not be so dramatic.
If the room lighting is unacceptable for viewing presentations or video,consider adding appropriate light fixtures. Specify dimmable wall fixturesor overhead tungsten lighting. Another factor to consider is ambientlighting - from windows, skylights and other sources. Add ambient lightsources to the drawings. Identify the primary light sources and indicatehow they are controlled. If possible, find out how light enters the roomduring different times of the day. Consult an interior designer todetermine your options for window coverings. Some windows or skylights mayrequire powered, remote-controlled window coverings.
When evaluating the acoustics of a viewing room, look at both the audiosystem and ambient noise. If the client is investing a sizable budget inthe room, you can justify enhancing the room acoustically. Consult anacoustical engineer, if necessary.
Begin by analyzing how well the room is insulated from outside noise. Use acopy of your drawings to record all the acoustical attributes of the room.Include such features as carpeting, wall types and windows. Intrusivenoises - traffic, HVAC systems and voices on the other side of the walldetract from the home theater experience. Most ambient noise cannot becontrolled. You must, if possible, prevent it from getting into the room.
Unwanted noise can also occur inside the viewing room, including the soundgenerated from the audience and the projector itself. Most of this noisecan be diminished through floor coverings and acoustical wall and windowtreatments. Evaluate how well sound travels in the room. Add the locationof the audio system loudspeakers to your drawing. Ideally, a person in theback of the room can hear the sound system voice as well as someone in thefront.
Power and grounding
Before beginning installation, make sure the power system and itscomponents are adequate to operate the projector and other componentssafely. Record the current electrical circuitry on the drawings. Notecircuit capacities and the number of circuits in the room. From theclient's electrical diagram, determine if any large equipment draws powerfrom the circuits that you plan to use. If the projector shares a circuitwith equipment in other parts of the home or apartment building, it may bedamaged. If you cannot ensure a clean, well-regulated power source, installa power-conditioning device.
The projector is likely to be the most demanding device you place online.Make sure that the system is capable of handling it in addition to othercomponents - audio amps, additional lighting, power curtains and videosystems. Do not depend on hardwiring the power to the projector and usingthe remote to turn it on and off. The projector must be switched.
Regardless of the complexity of the system you install, consider how theoperators will control the projector and other peripheral devices during apresentation. For simple installations, an IR remote may suffice. Determinewhat other A-V equipment must be controlled. Each source should beconveniently controlled either by the resident; the more you simplify theuser's interaction with the equipment, the fewer explanations you will haveto offer over the phone. A remote control allows the user to control thelights without leaving the comfort of his chair.
To centralize the control for a variety of sources, use a third-partycontrol system. Installing a custom control system makes it easy for aresident to control every aspect of a multimedia room - from projector andsound system to lights and curtains. Moreover, these systems allow moresophisticated projector control. For example, the controller can beprogrammed to synchronize multiple projectors. For a custom control system,devote a copy of your room drawing to the system. Note the type andlocation of the devices to be controlled.
While determining and installing the cables for a projection system, youmay be working with an electrical contractor, an audio specialist and adata/video equipment installer. Once you know the number, type and locationof all equipment to be installed or cabled into the system, add theinformation to the drawing. List all of the signal sources, signalreceivers and processors. This will help you determine where you are goingto run the cables, the type of cables the installation requires and theamplification. Be sure to conceal the cables along the walls and ceiling.Keeping the cables completely out of sight can go a long way towardpreserving a room's aesthetics, which is critical when installing insomeone's home.
Dropped ceilings offer the advantage of a concealed space above the ceilingtiles in which you can hide cables. If you are not working with a droppedceiling, find out how the electrical circuits have been run. You may needto share that space.
On a copy of your room drawings, show all planned connections betweensystem components and the projector. Include the types of cables youpropose using and the approximate cable lengths. You will use the drawingto determine locations for such special interface devices as adapters,synchronization boxes, distribution amps and decoders.
Once you have installed the projector and other required peripherals, youmust test the system, fix any problems and walk the client through itsoperation. Double-check all system components to make sure they operateproperly. This includes projecting all the different types of images thesystem is capable of projecting. Make sure each component is adjustedproperly. If the equipment does not work as expected, isolate the systemthat is causing the problem first. Check the cabling.
When you are satisfied with the system's performance, review its operationwith the client. This process includes everything from powering up theprojector, to operating remotes, to setting appropriate audio levels.Discuss proper room lighting, even if you did not install alighting-control system. Indicate how audience seating can influence theperception of a presentation.
Finally, leave printed instructions for all equipment. Make sure the clientunderstands that proper maintenance is essential to protect the projectionsystem. Remember that it is critical to ask the right questions up frontand record the answers carefully. Review your progress with the client, andinclude any changes to the original plan. Do not forget the client'soriginal concept of the system - what he saw that sold him on the system.That will be your benchmark. By following the process outlined here, youcan be confident your installation will be a success.