Gibilisco - Acoustics, Audio, And High Fidelity

20 Questions | Total Attempts: 140

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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.