This should get you well on your way to a professional looking equipment installation that will provide years of service. If you care about such things, you might even impress your friends.

Home Theater Design and Construction - Part 8

Steve Faber | Home Theater Design and Automation

Home Theater Design and Construction - Part 8
by Steve Faber
 Home Theater Design and Automation

This should get you well on your way to a professional looking equipment installation that will provide years of service. If you care about such things, you might even impress your friends.

Click here for Part 1
Design Considerations
Click here for Part 2
Construction
Click here for Part 3
Speaker Placement
Click here for Part 4
Room Acoustics and Lighting Design
Click here for Part 5
Time To Start Shopping 
Click here for Part 6
Component Features and Performance 
Click here for Part 7
Component Features and Performance 


Everything seems to be in place. There are no shorted wires or cables and all your in-wall or in-ceiling speakers, if you have them, are installed. You really are on the home stretch now. Just a little equipment hook up, programming, and calibration separate you from having a great movie night in your new home theater. The question before you at this point is: "What to do with this bundle of wires coming out of the wall?"

That depends upon how you'll be housing your gear. If you have installed an equipment rack, such as the ones from Middle Atlantic, then you need to be sure you have enough length on your wires to allow for effective, and neat, cable management. An equipment rack will allow some equipment to screw right to the front of the rack, into metal bars with a row of screw holes. These bars are known as 'rack rails'. Equipment that doesn't have the provision to bolt directly to the rails can be installed on a special, rack mountable shelf.

If you have rear access to your rack or equipment shelf, the job will be so much easier. Another option is to mount the rack or cabinet on casters and allow it to roll out of its wall niche and into the room for easy access. Several manufacturers build racks that are fixed into the cabinetry, but extend into the room and rotate to allow easy access to the back of the equipment for equipment installation and servicing. This is a great option if you have no access to the back of your gear.

The alternative to having the rack roll or extend is to allow long enough wire trunks to enable the equipment to be removed from the shelves. Needless to say, this creates wire management problems, and is nowhere near as neat or tidy. It's nice to make the back of the rack look like it was wired by an aircraft or marine electrician. The trunk to the rack should be in one neat bundle, with all the wires running parallel to each other. At each piece of gear they should branch off and run parallel to the rear panel of the equipment until they reach their connection point, where they will make a gentle, 90 degree bend, and go into the appropriate connection. Wire lacing bars make this much easier. Wire lacing bars screw onto the rear rails of the rack, and give, as their name would suggest, a support on which to tie the cables.

As you run your wiring in the rack, you'll want to make sure every wire or cable, weather it originates in the rack, or comes from the wall, is clearly labeled. The easy way is to use a permanent marker and white electrical tape. That is not the preferred method, though. A much nicer and more legible solution is to use a label maker, such as those available from Brother or Rhino. Both work well, and models are available that have markings specifically for electronics and electrical jobs. There are many types of label tape available. Thankfully, you can get tape made for adhering to wire and cable. It is flexible and has special adhesive to make the labels very secure. Place the labels within a few inches of the end of the wires, so you can easily locate and read them. You'll have a much neater job using wire labels, and serviceability of your system will be much improved.

One great way to ensure you don't have too much excess cable in your rack is to use custom terminated cables wherever possible. This will allow you to cut everything to the precise length needed. There are multiple solutions in this area. Antec-DigiCon compression ends work very well and are used as OEM by several cable TV companies. They are available with different ends, such as BNC, 'F', and RCA depending upon the application. They also make ends for different types of cable, such as RG-6 or 6quad, RG-59, and mini high res, so you can use them for RF, video, line level audio, and coaxial digital audio, depending upon your application.

You'll need a special compression tool to install the ends. A common one is the Leviton 40989-CPT. It's also necessary to have a special tool to strip the different cable layers to the correct length. These are available from Leviton, Eclipse, Stirling and Ideal. Do yourself a favor and pick one of these up as well. Whatever you do, do not, under any circumstances, use the cheap, crimp on fittings, like your electrician did in 1988 when your house was built. Yes, they sell them at Home Depot, Lowes, and Radio Shack, but they make a poor connection, don't last, allow water into the cable, and have poor bandwidth. Any of the above reasons by themselves are enough not to use crimp on ends. To make matters worse, your friend the CEDIA installer will have a hearty laugh at your expense when he sees them.

The cable is available in different colors as well, allowing you to appropriately color code the cables. Comm-Scope and Belden make great cables for this type of application, and others exist as well. Coaxial cables are very sensitive to geometry, so as with the pre-wire, it is important not to disturb the proper geometry during your wire routing. The reason is because coax cables, especially when used for RF applications transmit the signal using (big buzzword coming) transverse electrometic (TEM) wave field distribution propagation within the transmission line, or coaxial cable (according to Belden). You can mess up all this propagation by putting a nice kink in the cable.

It's good practice to route the signal cables on one side of the rack or shelf, and power on other side. The separation will minimize noise picked up by your cabling. It's also easier to service the system in the future. If possible, use only equipment with detachable, IEC style power cords, like your computer. This will save you from having to remove the power cord when repairing or replacing a piece of electronics. When you bundle and tie the cables, use Velcro ties, instead of nylon zip ties. They are reusable, so if you forget or need to add or remove a wire, you can simply loosen them, and re-secure them when you're finished. They are also wider than nylon zip ties, so they put less pressure per unit of area on your cable bundles. This helps to prevent cable distortion.

One other thing; don't forget proper thermal management. Your electronic equipment is like you are. Too much heat can kill them or make you replace them far too soon. If your rack or equipment is installed in a closed cabinet or niche, use venting to promote proper airflow. You can use a thermostatically controlled fan to evacuate heat form the area. A super quiet bathroom fan works well, or you can use a remote, in-line fan, such as those available from Fan-Tech. Remember, you can't just pull air from the area, you have to allow for fresh air to replace it.

This should get you well on your way to a professional looking equipment installation that will provide years of service. If you care about such things, you might even impress your friends. In any case, you get to have years of home theater enjoyment.


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