5-Minute Tech Quiz

1. AC3 is another name for Dolby Digital.

a. True

b. False

2. Which speaker is primarily used for dialog?

a. Center

b. Tweeter

c. Subwoofer

d. None of the above

3. Which speaker primarily delivers the low bass frequencies?

a. Center

b. Tweeter

c. Subwoofer

d. None of the above

4. Which speaker primarily delivers the high frequencies?

a. Center

b. Tweeter

c. Subwoofer

d. None of the above

5. Active speakers include their own amplifier.

a. True

b. False

6. A video scan technique where the odd lines are scanned first and then the even lines is called:

a. letterbox.

b. interlaced.

c. progressive.

d. All of the above

e. None of the above

7. Generally speaking, the bandwidth of human hearing is 20 to 20,000 Hz.

a. True

b. False

8. All analog television sets will require a converter when broadcasters switch to digital broadcasting.

a. True

b. False

9. When will full power broadcast television stations stop broadcasting analog and switch to digital only?

a. December 2008

b. February 2009

c. December 2009

d. January 2010

10. An S-video cable contains both video and audio signals.

a. True

b. False

11. A process that horizontally condenses a 16:9 image into a 4:3 space is called:

a. anamorphic.

b. diffusion.

c. letterbox.

d. All of the above

e. None of the above

12. The aspect ratio for a widescreen image is 16:9.

a. True

b. False

13. When running home theater cables, you should keep them away from electrical cables and machinery.

a. True

b. False

14. You can use the same type of speaker cable regardless of location.

a. True

b. False

15. Which of the following connection techniques provides the highest quality video?

a. Component

b. DVI/HDMI

c. RF

d. All of the above

e. None of the above

5-Minute Tech Quiz Answers

1. a

2. a — The center speaker is used primarily for dialog and some on-screen sounds and should be mounted centered directly above or below the screen.

3. c — The subwoofer is designed to deliver low frequency sounds and may be powered or not powered.

4. b

5. a

6. b — The odd and even fields are aligned so that the human eye sees them as one image.

7. a

8. b — Some satellite and cable customers will not require converter boxes. Those receiving their broadcast television signals directly from an over-the-air antenna will need a converter box.

9. b

10. b — The S-video cable contains only the video signals. Another cable must be used for audio information.

11. a

12. a

13. a — Home theater cables can be susceptible to electrical noise and induction if run too closely to electrical cables or electrical devices, such as motors and fluorescent ballasts.

14. b — The length of the cable run determines the AWG size of the cable, and the environment where it is run determines if a special cable type, such as plenum or outdoor, should be used.

15. b — Of the video types listed, RF provides the lowest quality and DVI/HDMI provides the highest.

What’s Wrong with This?

Wally `Larman was installing a security system for a residential customer when he was asked if he could run the cables for a home theater system. Since he was running cables through the house, Wally agreed to run the cables and pulled a 22/4 cable to each speaker location as shown in this diagram. When he was finished, he carefully tested the cables for opens, shorts and grounds and found no problems. Everything seemed OK but when the home theater installer arrived, he had a problem. Can you see what Wally did wrong and what he must do to correct the problem?

Answer to: What's Wrong with This?

Wally’s problem is caused by the type of cable he ran for the speakers. 22/4 may be great for security systems, but high-quality home theater systems require a better grade of cable. The size (AWG) depends upon the cable length, but because the cable lengths are short, Wally should be able to use 16/2 or possibly 18/2. He should speak to the home theater installer and find out exactly what type of cable he wants run before repulling the wires. You should always check to see what type of cable is required anytime you are running cables for other contractors. Because running the wrong cable type can result in improper system operation and reduced customer satisfaction as well as profit, it is a good idea to get the requirements and locations in writing before you start your work so that there are no misunderstandings.