Psychoacoustics Final Exam

Psychoacoustics Final Exam Which of the following best describes the relationship between time and frequency representations of a pure tone signal? a) Multiplicative b) logarithmically related c) inverses of one ano ...

Psychoacoustics Final Exam Which of the following best describes the relationship between time and frequency representations of a pure tone signal? a) Multiplicative b) logarithmically related c) inverses of one another d) additive e) related by power law - ANS - Inverses of one another One complete cycle of a sinusoidal wave represents a) a frequency of 1000Hz b) a 360-degree phase change c) two wavelengths d) a half-period e) compression - ANS - a 360-degree phase change A sine wave that has a frequency of 200Hz has a period of a) .2 seconds b) .002 seconds c) .02 seconds d) .005 seconds e) .05 seconds - ANS - .005 seconds We use a Fourier analysis to a) Measure the amplitude of a waveform at each frequency b) Decompose a periodic signal into component sinusoids c) Produce a plot of the frequencies that are present in the signal d) both b and c e) a, b, and c - ANS - a, b, and c Which of the following scales is used to measure the magnitude of any sound in the environment? a) dB HL b) dB SL c) dB SPL d) dB IL e) both c and d - ANS - both c and d Every increase of 20dB HL on the audiometer dial corresponds to a) a 10dB SPL increase in the output of the transducer b) a ten-fold increase in the pressure of the sound transmitter c) no change in dB SL for audible signals d) both a and b e) a, b, and c - ANS - a ten-fold increase in the pressure of the sound transmitted If the raw sound pressure measured from a loud speaker is 3Pa and I I increase the output by +6 dB SPL, what will the new measured pressure be from the speaker? a) 8 Pa b) 2 Pa c) 1.5 Pa d) 6 Pa e) 30 Pa - ANS - 6 Pa Having access to RETSPL information is important in audiology because a) normal hearing thresholds occur at the same sound pressure level for all frequencies b) earphones, bone oscillators, and speakers produce the same sound pressure from an audiometer set at the same dB HL c) for any dB HL setting on the audiometer, the dB SPL output varies by frequency and type of transducer used d) patient thresholds differ when tested in sound field versus under earphones e) a patient's response bias can have an impact on how accurate their threshold may be - ANS - for any dB HL setting on the audiometer, the dB SPL output varies by frequency and type of transducer used The upside-down audiogram is beneficial for interpreting hearing loss because a) it represents a patient's loss of sensation relative to the minimum audibility curve b) it avoids the elliptical shape of average human hearing across the range of frequencies c) it can predict how well a person understands speech in both quiet and noise d) both a and b e) a, b, and c - ANS - Both a and b If a pure tone has a very short duration of 1--10 microseconds, a) energy will be very concentrated in its center frequency and it will be very specific b) spectral splatter will produce off-frequency peaks and nulls c) it will be especially useful for pure tone audiometric testing d) a and b e) a, b, and c - ANS - Spectral splatter will produce off-frequency peaks and nulls If the bandwidth of a spectral peak is 2/d where d is its duration, what is the bandwidth of energy around a 1000Hz pure tone with a duration of 500ms? a) .002 Hz b) 2 Hz c) 4 Hz d) 5 Hz e) .5 Hz - ANS - 4 Hz To measure the sound pressure level achieved when combining any two sounds, you a) add the dB SPL values of the two sounds together b) calculate the numeric average of the two dB SPL values c) convert the dB SPL to their pressure values, add those together, and recalculate dB SPL from the result d) either a or c e) both b and c - ANS - convert the dB SPL to