June 1999. Welcome back. By now you've read about my equipment selection in Part One and my paper design in Part Two. Now it's time to start putting it all together.

Construction

The position of the projector with respect to the screen is critical. CRT projectors typically have fixed focal length lenses (most LCD and DLP projectors have zoom lenses that permit changing image size). So there's an optimum throw distance for every image size. You've heard the expression measure twice, cut once. Well, in this theater it was calculate thrice, measure twice, cut and build once. After making very sure that I'd figured out the correct throw distance, and that I'd compensated for the thickness of the wallboard and screen frame, I carefully drew the first line on the floor. It was the front edge of the 2x6 floor-plate for the wall that held the screen. I then marked the center of the room on that line (I had already checked that the framer had correctly centered my projector mounting threaded rods). All the other floor-plate outlines were referenced to that first line and the center mark. Once the first line was down the rest flowed rather easily. I wanted to mark the floor-plates personally. Distances and positions were just too critical to chance a contractor error. If it was screwed up, I wanted no one to blame but myself.

Framing and the inner face of the sheetrock went up without a hitch (although there was some grumbling about the use of 2x6s and overdesign). Next, outlet junction boxes and in-wall electrical wiring went in (AC power, IR sensor cable, and IR emitter cables at curtain locations - no audio or video, they would be surface mounted later). Room lighting and its wiring was completed during the build of the outer shell. Next, I had a spray-foam insulation contractor come in to fill the voids between the studs in all the inner room walls. And here I made a distinct (but not critical) error.

If you'll recall from my previous chapter, the reason that I chose to use spray-foam was to stiffen the walls to reduce any flexing that could potentially cause resonances. Such resonances could affect the in-room frequency response. While I ensured that the foam I chose posed absolutely no environmental hazard (no outgassing, like formaldehyde), I did not ask for samples to judge stiffness. I now know that there are spray formulas and there are pour formulas. The latter is denser and stiffer. A pour formula is normally injected through small holes drilled in the gypsum and between studs after both faces of wallboard are installed. The spray formula is applied while one side of the wall is open, the expanding foam is then shaved flush with the studs, and the second side of wallboard is installed. If you choose to apply foam, shop around, consider different installation techniques, and request samples. Select the stiffest, highest density foam you can afford (and that's environmentally safe). The plan called for the walls to be acoustically inert. Rapping on any wall between studs should produce a simple, dull, muffled thud. My walls were very much improved over conventional construction, but the slightest low frequency resonance remained. It'll be interesting to see if acoustical instruments can pick it up.

(Note: do not use foam in walls that are constructed with double studding to disconnect the inner face from the outer face (see the previous chapter). This will couple the two faces and you will lose isolation as you gain stiffness.)

The spackling contractors came next. I sealed the returns and kept the door closed when they got around to sanding the walls. What a mess. They understood the special nature of the room and did a particularly fine job. When they finished, I thoroughly vacuumed the floor and washed the areas where the steps and seats would be installed.

To save money during the special pour for the pits in the floor, I simplified the design to easily fabricated rectangles. Now I had to construct two large odd-shaped steps, each precisely six inches high, for the decent from the upper seating level to the lower seating level. I used conventional framing techniques with 2x6s. All the joints were nailed and glued with Phenoseal. The frame was then glued to the floor with more Phenoseal, and secured with masonry nails. Plywood of a thickness that would build up the step to six inches was then glued and nailed to the frame. After the carpeting was laid, I didn't want anyone to be able to tell the difference between the concrete and wood. No creaks. No movement. Lots of Phenoseal.

Next, the theater seat mounts. I had selected six high-backed, rocking, home theater seats finished in burgundy velour and manufactured by Irwin Seating Company. Irwin also made available bolts of matching fabric, which would be used for the drapes. Like movie theater seats, these chairs are not free standing. They have small bases with bolt patterns punched in the sheet metal. So the seats had to be bolted to the floor. A concrete floor. Installing an array of masonry fasteners caused some concern. I was worried that the concrete would crack as people rocked in the seats; concrete is only good in compression. I decided to have two tenth-inch thick steel plates made; each was sized big enough to support a row of seats. Very heavy. I carefully marked and drilled holes in the steel for the seats. I then filed the holes into squares to accommodate carriage bolts to be poked up through the bottom (the plates were too thick for a punch). The square underside of each head would engage the square hole and prevent it from spinning when I torqued down the nuts on the bolts holding the seat bases. I ground slight depressions in the concrete to accept the protruding topside of the bolts' heads, which were on the bottom of the plate. The plates were then glued down and bolted to the floor with masonry fasteners. Very secure.

The ceiling, front wall, and "stage" area were painted flat black, as were any pieces of hardware that would be mounted on a black surface (supply and return grills, top-hat light fixtures, and the NEC projector's mounting bracket). To color-match the burgundy fabric, I took a sample to my local paint store. There, we discovered that the optical scanners used to match colors did not like velour at all. The paint had to be color-matched by hand. I worked with the mixer until we were both satisfied with the match. Several coats of paint later, the room was ready for carpeting.

To capture the feeling of a classic movie palace, I had decided to add the decorative touches of crown molding (Home Depot), resin appliques (Outwater Plastics Industries), and columns (HB&G). I chose smooth, round, split, eight-inch columns, each with a Roman Corinthian Capital and Attic Base. The thick pile carpeting would partially obscure the column bases, and the carpeting had to be installed around the bases, so I fabricated a few special parts. I traced, cut, and matched half-inch plywood pieces to each column base. I then painted them black and attached them to the floor with masonry fasteners where the columns would be mounted. The carpeting contractor then installed around these wooden plates at the column base locations without my having to risk his damaging the bases (and I avoided some obscuring of the bottoms of the columns). The carpeting installer also did some serious grumbling. Many bends, peculiar shapes, and pieces. Four elevations and odd steps. And 32 bolts sticking up from the floor. These guys really prefer large flat areas.

This is an appropriate place to mention that as I planned my theater, I realized that if I should ever sell my home, the next buyer may or may not want to invest in this room. So I designed the theater so its contents could be moved. The inner walls, the carpeting, the seats' mounting plates, and the steps would, of course, all have to stay; but, everything else would be designed to go. So I had to devise a temporary but strong method of mounting the columns. I fabricated aluminum brackets that attach to the wall with mollies and extended out into the hollow, split columns. Mollies were also mounted on the column sides of these brackets. Holes for the brackets were drilled in the columns where the bases and capitals would be mounted, so the screws would be hidden. After I painted the columns, it was a simple matter to stand each against a wall and hold it in place with a couple of screws (the columns would stand on their own, so two number-eight machine screws were more than adequate). The capitals and bases were then glued in place with silicon rubber adhesive, strong but temporary. The appliques also went up with silicon adhesive.

I decided to hang the surround speakers directly on two columns just below the capitals. This may seem like a strange choice, but... The speakers are black, the columns are black. The speakers are slightly wider than the columns. The columns are in good positions to locate surround speakers. When mounted, the surrounds will tend to visually melt into the columns. So I mounted the metal speaker brackets on two columns and drilled holes for the speaker wires before the columns went up.

The screen was bolted to the wall, taking great care that it was level. The NEC mounting bracket was bolted to the ceiling and the threaded rods trimmed. I rented a Hi-Jack from my local Taylor Rental, a device capable of lifting 500 pounds to a height of over eight feet. It was used to mate the projector to the ceiling mount - very carefully. Do not try this alone! It takes at least on person on the lift and another to guide the projector onto the bracket.

The bolts of velour fabric had been sent out to a custom drapery contractor. He came in and installed all the drapes. There are nine drapery panels; the screen is split, so it counts as two. Three would be against the back wall and be opened only to access electrical outlets or the central vacuum cleaner connection. One would cover the door to the service area, and one would cover software storage. I specified Makita motorized rods for the remaining three locations: the entrance, the equipment rack, and the screen. And wasted more money. I find that I use the entrance and equipment rack drape controls all the time - very handy, no regrets. Originally, I had visions of programming a sequential macro into my universal remote control to close the entrance drape, close the equipment drape, open the screen drapes, dim the house lights, dim the screen floods, then start the movie. Very dramatic, very much like a classic movie theater. Very unnecessary. In practice, I find that the screen drapes are open all the time. If I had it to do over again, I'd eliminate the cavities on either side of the screen and I'd eliminate the screen drapes and their Makita motorized rods.

I fabricated speaker platforms from three-quarter-inch particleboard. I mounted them behind and flush with the bottom edge of three speaker-sized holes in the speaker mounting board below the screen. The left and right platforms were toed in. The angle was calculated based on the high frequency directivity pattern of the speakers and the locations of the seats. The platforms were glued and screwed in place, then painted flat black. Black silicon-rubber weather-stripping was applied to the top surface of each platform. The left, center, and right speakers were placed on the rubber strips and slid forward until they were as close to flush as possible. They neither vibrate nor move. The subwoofer was moved into its opening, slid forward, made flush, and the feet adjusted.

The equipment rack was jostled into place and the legs were adjusted to gently snug the rack up against the top of the wall opening. All the equipment was then racked and interconnected. Which brings me to...

Wiring And Cabling

I've read endless debate over the merits or lack of merits of obscenely expensive cables. I'm in the latter camp.

Film audio is far from purist quality. Innumerable layers of elements, a combination of looping and original dialog, recorded sound effects and Foley stage effects, multi-mike score recording, and mutli-channel mixes all contribute to dramatic sound, but hardly represent a natural acoustic environment. And even if it did, I have yet to find any engineering basis for exotic cable claims. Particularly for the short runs I have in my home theater system, any respectable audio cable would do. My only special requirement is that the audio cables have gold-plated connectors. Gold doesn't oxidize, so the resistance of the connection will remain low. I use Radio Shack Gold Series prefabricated audio cables.

The digital audio connection between the Sony DVD player and the B&K decoder is coaxial cable. I have yet to hear the slightest difference between a coaxial cable and an optical digital connection in any high quality home theater. If there are no ground loops in the coaxial connection, I doubt that any audible differences exist.

As for video, as long as the coaxial cable has the correct impedance and the distributed reactance doesn't place a stressful load on the source component, the video image should remain unaffected. I found that the best solution for me was to buy a 500-foot reel of Belden type 9240 (low-loss RG-59) coaxial cable, and Amp crimp tools and connectors. I then fabricated all my own high quality cables to minimum length. This decision was made before the outer walls went up. I had to prewire the video cables in the ceiling (RGB-HV plus a spare) before the gypsum was applied to the ceiling.

Speaker wire may be the most hyped of all. From my point of view, all that's required is to keep the resistance as low as possible between the power amplifier and the loudspeaker. This keeps the damping factor high and the speaker is better controlled by the electronics. High frequency considerations in cable structure are irrelevant at audio frequencies as long as the cable doesn't contribute excessive reactive impedance. The speaker conductors in my audio system, upstairs in the living room, are very thick; each is almost a quarter-inch in diameter after the insulation is stripped off. But that wiring is for full-range speakers. My home theater M&Ks reproduce sound from about 100 Hz and up; the subwoofer does the rest. So damping factor is less stringent. For the theater, I chose heavy 12/2 lamp-cord style wire.

That leaves the sub-woofer with its integrated power amplifier. Here too, I fabricated my own cable. Since the frequencies are all below about 120 Hz, this is perhaps the least critical coaxial cable of all. I used a length of spare RG-58 cable and soldered a gold-plated RCA connector on each end.

IR Lighting Control

I had three requirements: that the lighting could be controlled with my universal remote control; that the lights could be made to automatically dim rather than simply switch off; and, that the controller could replace the three-way switches the electrician originally installed. Again, I was trying to capture a movie theater effect. Fortunately, such a product exists; it's the Lutron Spacer. I bought two, one for the overhead, recessed, top-hats, and one for the two miniature floods installed between the front valance and the screen. The Spacers work very well. My only gripe is that you cannot control the two dimmers independently, so dimming the lights sequentially is not possible.

IR Distribution System

To control everything in the theater from one hand-held device that I can see in the dark, I chose the Marantz RC-2000 learning remote control. All the buttons are backlit, as is the programmable liquid crystal display. It has macro capability. It should work well, but will it learn odd codes like the Makitas and the Lutrons? In a word, yes. What a relief. But all the IR sensors are hidden behind heavy drapes. And the Lutrons are in another room, the service area. So how do I get the IR signals from my remote control to all my components? An IR distribution system.

An IR distribution system is composed of three parts. The first is a centrally located sensor, built right into the wall. (I put mine above the center of the screen where it would be illuminated by the Marantz remote as I held in my hand at a natural angle.) The IR sensor picks up the signal from the remote and sends it to the second part, the distribution amplifier. The amplifier accepts the signal from the sensor, buffers it, and sends it out through a bunch of connectors. You plug IR emitters, the third part in this chain, into the amplifier's connectors. Each tiny emitter has a self-adhesive surface that you press onto the IR sensor on the component to be controlled. Or, if a component (like my B&K AVP-3090) has a control port as well as an IR sensor, you can use a miniature phone-plug direct connection. Xantech is the manufacturer. The products I bought include the 10-emitter connecting block (amplifier), double and single mini stick-on IR emitters, and a round IR sensor that mounts in a half-inch hole.

The two Lutrons, the three Makitas, the Sony DVD, the B&K decoder, and an older Sony TV tuner for the rare off-the-air program were all connected. I trained the Marantz with the original remotes, programmed its display, and I was in business, with two exceptions. My early model Faroudja doesn't have an IR remote control. But it does have a remote control port; so I had to make my own remote control. Velleman, a Belgium manufacturer, makes IR remote control kits. I bought their IR transmitter (the handheld remote control) and their Universal Relay Card. Luckily, the Marantz was able to learn the Velleman codes. This allows me to control all the push buttons on the line doubler, but I have yet to find an appropriate and reasonable source of motorized potentiometers for the Faroudja analog adjustments (if anyone knows of a good source, please let me know). Also, my JVC professional Super-VHS deck doesn't have an IR remote control. I decided to let this one slide. This tape machine gets used less and less and it's my intention to replace every tape in my library with its DVD counterpart (thirty-nine to go).

(You may ask why I own prerecorded tapes but not laserdisc? The answer is that I'm very intolerant of disc-swap or side-flip interruptions. They destroy my willing suspension of disbelief. So I tolerated the awful quality of tape while waiting for the inevitable better video source. And then DVD arrived.)

Power Conditioning

I live in an area where an occasional, brief power failure is common. A fraction of a second to a minute is typical. This may happen about two or three times each month. For such power disruptions, the projector, the line doubler, the DVD player, and the decoder will all shut down - talk about interrupting your willing suspension of disbelief. So to avoid such annoyances, I installed two powerful uninterruptible power supplies (UPS). A UPS contains a large battery and an inverter, a circuit that produces AC line voltages from the low voltage of a lead-acid gel-cell battery. If a UPS detects a power failure, it immediately kicks in the inverter, preventing system shutdown. (As you might expect, I have a UPS on my computer, a more typical application, and on my upstairs audio system.) This approach has a few other advantages as well. The Sony DVD player will lose all its user settings if left unpowered for several minutes; the UPS prevents this. And the UPS contains serious surge suppression to protect my electronics. My two home theater units are rated at 1400 volt-amps each. I split the electrical load from my electronics as equally as possible between the two. APC is the UPS manufacturer.

Two More Mistakes

I had planned to remove the manufacturer's grill cloth from the front speakers and install a single, wide frame covered with black grill cloth in front of them. I bought the grill cloth, a roll of Velcro, and built the frame. But when I saw how the recessed M&Ks looked, I decided it wasn't necessary. A bit more cash wasted.

When I had my home built, I remembered to specify remotely mounted bathroom exhaust fans. These are fans that are ten or twelve feet away from the bathroom ceiling and connected to the air intake grills by flexible, sound-absorbing ductwork. This arrangement makes for a very quite exhaust fan. So how could I forget the NEC projector's internal exhaust fan? The theater is so quiet that the projector fan is obvious - not anywhere near as loud as the Sony VPL-W400Q LCD projector, for example, just obvious. I could have mounted a fan in the service area and brought flexible ducting to the projector above the ceiling. I could then have disconnected the NEC's internal fan. The cooling would have been better and the noise would have been diminished. In practice, the soundtrack virtually always masks the projector. But with the amount of time and energy I've invested in this room, I would have liked to have lost the fan noise. We learn by doing.

Coming In Part Four

Coming in Part Four, the system gets tuned, the Avia DVD is assessed, and (if they come out)...photos.

(If you have any questions or comments for the author, say hello to Mr. Blandings here.)