Gibilisco - Acoustics, Audio, And High Fidelity

20 Questions | By BATANGMAGALING | Last updated: Jun 19, 2019 | Total Attempts: 159

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Gibilisco - Acoustics, Audio, And High Fidelity

Questions and Answers

1.

A young person can hear sounds at frequencies as high as approximately which of thefollowing?
- A.
  
  20 Hz
- B.
  
  20 kHz
- C.
  
  20 MHz
- D.
  
  20 GHz
2.

Electromagnetic interference to a hi-fi amplifier can occur in the presence of
- A.
  
  A nearby radio broadcast station.
- B.
  
  Improperly designed receiving antennas.
- C.
  
  Excessive utility voltage.
- D.
  
  Improper balance between the left and right channels.
3.

The midrange audio frequencies
- A.
  
  Are exactly halfway between the lowest and highest audible frequencies.
- B.
  
  Represent sounds whose volume levels are not too loud or too soft.
- C.
  
  Are above the treble range but below the bass range.
- D.
  
  None of the above are true.
4.

In the acoustical design of a room intended for a home audio system,
- A.
  
  The use of small speakers can minimize distortion.
- B.
  
  Reflection of sound waves from walls should be minimized.
- C.
  
  The walls should all intersect at perfect 90° angles.
- D.
  
  Wooden furniture, without upholstery, should be used.
5.

A change of +10 dB in an audio signal represents
- A.
  
  A doubling of acoustic power.
- B.
  
  A threefold increase in acoustic power.
- C.
  
  A tenfold increase in acoustic power.
- D.
  
  No change in acoustic power, but a change in frequency.
6.

What is the frequency of an acoustic disturbance whose wavelength is 120 mm in air?
- A.
  
  279 Hz
- B.
  
  2.79 kHz
- C.
  
  35.8 Hz
- D.
  
  358 Hz
7.

What is the frequency of a sound wave that propagates at a speed of 1100 ft/s?
- A.
  
  33.5 Hz
- B.
  
  335 Hz
- C.
  
  3.35 kHz
- D.
  
  Forget it! The frequency of a sound wave is independent of the propagation speed.
8.

The relative phase of two acoustic waves from the same source at the same time, one wavedirect and one wave reflected from a wall, can affect
- A.
  
  The positions of antinodes and nodes.
- B.
  
  The perceived frequency.
- C.
  
  The positions of antinodes and nodes, and the perceived frequency.
- D.
  
  Neither the positions of the antinodes and nodes, nor the perceived frequency.
9.

In an acoustic sine wave,
- A.
  
  The frequency and phase are identical.
- B.
  
  The sound power is inversely proportional to the frequency.
- C.
  
  The sound power is directly proportional to the frequency.
- D.
  
  All of the sound power is concentrated at a single frequency.
10.

Vinyl disks are
- A.
  
  Susceptible to physical damage.
- B.
  
  Useful primarily in high-power sound systems.
- C.
  
  Digital media.
- D.
  
  Preferred for off-the-air sound recording.
11.

If an amplifier introduces severe distortion in the waveforms of input signals, then thatamplifier is
- A.
  
  Not delivering enough power.
- B.
  
  Operating at the wrong frequency.
- C.
  
  Operating in a nonlinear fashion.
- D.
  
  Being underdriven.
12.

Suppose a 10-W amplifier is used with speakers designed for a 100-W amplifier. Which ofthe following statements is true?
- A.
  
  The speakers are capable of handling the amplifier output.
- B.
  
  The amplifier might be damaged by the speakers.
- C.
  
  Electromagnetic interference is more likely to occur than would be the case if the speakers were designed for a 10-W amplifier.
- D.
  
  The speakers are likely to produce excessive distortion.
13.

Which of the following frequencies cannot be received by an AM/FM tuner?
- A.
  
  830 kHz
- B.
  
  95.7 kHz
- C.
  
  90.1 MHz
- D.
  
  107.3 MHz
14.

Which of the following statements about woofers is true?
- A.
  
  They are especially useful for reproducing the sounds of barking dogs.
- B.
  
  They are designed to handle short, intense bursts of sound.
- C.
  
  They should not be used with graphic equalizers.
- D.
  
  They are specifically designed to reproduce low-frequency sounds.
15.

Suppose you have an amateur radio station and its transmitter causes EMI to your hi-fisystem. Which of the following would almost certainly not help?
- A.
  
  Build a new transmitter that works on the same frequencies with the same power output as your existing transmitter.
- B.
  
  Reduce the transmitter output power.
- C.
  
  Install shielded speaker wires in the hi-fi system, and be sure the system is well grounded.
- D.
  
  Move the amateur radio transmitting antenna to a location farther away from the hi-fi system.
16.

In an analog audio tape recorder/player, the recording head
- A.
  
  Converts sound waves to radio signals.
- B.
  
  Converts sound waves to fluctuating electric current.
- C.
  
  Converts AF current to a fluctuating magnetic field.
- D.
  
  Converts dc to AF current.
17.

A rack-mounted hi-fi system
- A.
  
  Can save floor space.
- B.
  
  Is more susceptible to EMI than a compact system.
- C.
  
  Is cheaper than a compact system.
- D.
  
  Is designed especially for use with vinyl disks and turntables.
18.

An audio mixer
- A.
  
  Cannot match impedances among interconnected components.
- B.
  
  Cannot increase the audio output of an amplifier.
- C.
  
  Eliminates EMI problems in all but the worst cases.
- D.
  
  Allows a microphone to be used as a speaker.
19.

Which of the following devices or circuits ordinarily employs D/A conversion?
- A.
  
  A portable CD player
- B.
  
  A turntable for use with vinyl disks
- C.
  
  An analog audio tape recording/playback system
- D.
  
  An RC tone control
20.

Which of the following is an advantage of digital audio over analog audio?
- A.
  
  Digital media can be used to record and play back audio at higher frequencies than can analog media.
- B.
  
  Multigeneration copies of digital audio programs can be made without degradation in fidelity, but this is not true of analog audio programs.
- C.
  
  Digital audio is compatible with vinyl disks and old-fashioned reel-to-reel and cassette tape, but analog audio is not.
- D.
  
  There are no genuine advantages of digital audio over analog audio. In fact, analog audio is superior to digital audio in every respect.