VDV Audio/Video Systems Installation 2 — Questions and Answers
Question 1: When installing ceiling speakers in a commercial space, what is the recommended minimum distance from a speaker to a wall to avoid comb filtering?
- 12 inches
- 2 feet
- 4 feet (Correct answer)
- 6 feet
Correct answer: 4 feet
Placing ceiling speakers at least 4 feet from walls minimizes comb filtering caused by early reflections interfering with direct sound.
Question 2: Which cable type is most appropriate for running a balanced audio signal over 100 feet to minimize noise pickup?
- RCA coaxial cable
- Unshielded twisted pair (UTP)
- Shielded twisted pair (STP) with XLR connectors (Correct answer)
- Speaker wire
Correct answer: Shielded twisted pair (STP) with XLR connectors
Shielded twisted pair with XLR connectors carries balanced audio signals, which reject common-mode noise over long cable runs.
Question 3: A projector is displaying a washed-out image in a room with high ambient light. Which specification should be increased when selecting a replacement projector?
- Throw ratio
- Contrast ratio
- ANSI lumens output (Correct answer)
- Aspect ratio
Correct answer: ANSI lumens output
Higher ANSI lumens output overcomes ambient light interference, producing a brighter and more visible projected image.
Question 4: What is the purpose of a rack-mount UPS (Uninterruptible Power Supply) in an AV equipment rack?
- To boost audio signal levels
- To provide clean power and protect equipment during outages (Correct answer)
- To cool the rack with filtered air
- To distribute HDMI signals
Correct answer: To provide clean power and protect equipment during outages
A rack-mount UPS conditions incoming power and provides battery backup to prevent equipment damage and data loss during power interruptions.
Question 5: When terminating an RJ-45 connector for a VoIP phone installation, which wiring standard is most commonly used in the United States?
- T568A only
- T568B only
- Either T568A or T568B, but consistently throughout the installation (Correct answer)
- CAT5e crossover wiring
Correct answer: Either T568A or T568B, but consistently throughout the installation
Both T568A and T568B are acceptable, but the same standard must be used consistently on both ends of every cable in the installation.
Question 6: Which video signal format provides the highest quality uncompressed signal for short-distance professional AV connections?
- Component video (YPbPr)
- Composite video
- SDI (Serial Digital Interface) (Correct answer)
- S-Video
Correct answer: SDI (Serial Digital Interface)
SDI carries uncompressed digital video and audio over a single coaxial cable and is the professional broadcast standard for high-quality short-distance connections.
Question 7: A customer reports that their newly installed flat-panel display flickers intermittently. What is the most likely cause when using an HDMI connection?
- Incorrect aspect ratio setting
- A loose or damaged HDMI cable (Correct answer)
- The display's contrast setting is too high
- Incorrect speaker impedance
Correct answer: A loose or damaged HDMI cable
Intermittent HDMI flickering is most commonly caused by a loose connection or a damaged cable failing to maintain a stable HDCP handshake.
VDV Audio/Video Systems Installation 2
When installing ceiling speakers in a commercial space, what is the recommended minimum distance from a speaker to a wall to avoid comb filtering?