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Exam Question Checklist

Exam 1998 Question 7

" How is the perceived loudness of pure tones related to their intensity and frequency? How does the perceived loudness of pure tones differ for listeners with a cochlear hearing loss?"

20 things you should mention:

  • Loudness
    • threshold of audibility for pure tones
      • sets quietest threshold
    • threshold of pain (uncomfortable loudness level)
      • set loudest sound
    • also limited by frequency to between 20Hz
      • and 20,000Hz
    • diagram of dBSPL vs frequency, showing audibility
      • axes correct
    • 20µPa to 200Pa range (140dB)
    • equal steps of loudness on logarithmic scale, i.e. roughly equal on dB scale
    • equal loudness contours -> pure tones of different frequency
      • that have same subjective loudness
    • loudness measured in phons / less sensitive at very low and very high frequency / contours not equally spaced
  • Impaired
    • cochlear loss = problem in detection of BM vibration
    • shifts threshold of audibility
    • but not threshold of pain
    • so very quiet tones -> inaudible
    • mid-loudness tones -> just audible
    • loud tones -> still painful
    • recruitment -> unnatural growth in perceived loudness with increasing intensity

© 2000 Mark Huckvale University College London