NSC/BCS 221: Audition Preparation Quiz 1: 22 January 2003

  1. What are the three basic physical attributes of sound? What are the primary perceptual qualities associated with each of them? (6 pts)
  2. What is the meaning of the word "otorhinolaryngology"? How would those who do this differ in their training from those trained in clinical audiology? (4 pts)
  3. What is an audiogram? (4 pts)
  4. In two or three sentences, what was the place theory of hearing? The temporal theory? (4 pts)
  5. In two or less sentences and a graph, what does a Fourier analysis of a sound wave provide? (4 pts)
  6. What are the two necessary characteristics of an object in order for it to vibrate? (4 pts)
  7. Graph one complete cycle of a sinusoidal wave with the axes labeled, and indicate the amplitude and the period, and the phase angle (in degrees) at any four points. Use any convenient frequency of the sine wave that could be heard by humans. Determine its period, and the approximate wavelength of your sine wave, if it is a sound wave in air. (Remember the speed of sound in air is about 340 m/sec, or 1000 ft/sec.) Would your sound wave cast a sound shadow around the head of a human listener? (10 pts)
  8. What is the difference between "peak-to-peak" amplitude and "rms" amplitude? Under what condition might these two be very different? (4 pts)
  9. What is Newton's equation for force? What is Hooke's equation? Why must both of these be used in tandem in understanding acoustics and auditory processing? (10 pts)
  10. In one sentence each, perhaps a formula, what is "work"? "power"? "pressure"? What is the relationship between acoustic power and pressure? (8 pts)
  11. The reference pressure used to calculate dB(SPL) is .0002 dynes/cm2. Suppose the pressure of a sound wave you are interested in measuring is 100 times this reference pressure. What would be its level expressed in dB SPL? (4 pts)
  12. What is the difference between dB (SPL), dB (SL), and dB (HL)? (6 pts)
  13. What are the different symbols of this formula, and what is its implication for hearing? (6 pts)
  14. Z = √(R2 + (Xm Ð Xs)2)
  15. For each of these formulas, (a) describe its meaning in words and (b) describe its implications for hearing -- either as a problem that the ear must surmount, or as providing a solution for some other problem. (4 points each)
    p = F/Ar ; _ = c/f ; I = p2/ _0c; f0 = c/(4L)
  16. Imagine a sound wave meets an object in its path: What determines whether the sound wave goes around the object, versus reflects back from the object? How is this effect important for hearing? (6 pts)
  17. Explain this figure (It is Figure 4.1 from Yost). (8 pts)

  18. You are presenting a white noise stimulus at 70 dB (SPL). Now you present a second white noise stimulus also at 70 dB (SPL): what is the dB of the combined stimuli? Suppose you doubled the power of each noise: what is the measured dB of this combination? (4 pts)
  19. Suppose you are presenting two tones, one at 100 Hz and the other at 105 Hz. What would the Fourier transform of this situation look like? What would it sound like? (4 pts)
  20. Suppose you are presenting a tone at 100 Hz and modulating its amplitude by a sinusoid that has a frequency of 10 Hz. What would the Fourier transform of this situation look like? What would it sound like? (4 pts)
  21. How does the resonant frequency change when the mass of the vibrating object is increased? When the stiffness of the vibrating object is increased? (4 pts)
  22. What are the frequencies of the first 3 octaves of a base frequency of 300 Hz? Of the first 3 harmonics? (4 pts)