TUTORIAL ANSWERS 350-370

 

 
 

Your Answer to Q350.  Sorry, your answer is not correct. How often does the wave shape repeat?

Help: Fundamentals of Sound, Sec. 8-B.

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Hint for Question 350:  The repeat time is the time between identical pulses. How is repeat frequency related to that?

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Your Answer to Q350. Congratulations, your answer is correct.

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Correct Answer to Question 350:  The repeat time is the time between pulses, which is 0.008 s. The repeat frequency is the inverse of this or 1/0.008 = 125 Hz. This is typical of the pitch of a voice.

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Your Answer to Q355.  Sorry, your answer is not correct. The glottal wave has not yet been filtered through the vocal tract.

Help: Fundamentals of Sound, Sec. 8-B.

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You should try to work out the answer on your own, but if you insist on reading it the correct answer is here.

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Hint for Question 355.:  What is the repeat frequency of each wave?
 
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Your Answer to Q355. Congratulations, your answer is correct.

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Correct Answer to Question 355:  The repeat frequency of the wave on the left is 1/0.008 = 125 Hz and that on the right is 1/0.01 = 100Hz. Thus the the speaker having the left wave will have a higher pitched voice. The shape of individual pulses is the same although they occur at a different frequency. The two waves do not yet represent speech sounds because the glottal waves have not been filtered by the vocal tract. The correct answer is simply b).

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Your Answer to Q360.  Sorry, your answer is not correct. Recall what are the standing wave frequencies of a tube open at one end and closed at the other end.

Help: Fundamentals of Sound, Sec. 3-D, 8-C.

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Hint for Question 360:  The lowest resonant natural frequency for a tube open at one end and closed at the other end is f0 = v/4L.

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Your Answer to Q360. Congratulations, your answer is correct.

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Correct Answer to Question 360:  The lowest resonant standing wave frequency for a tube open at one end and closed at the other end is f0 = v/4L = 1100/(4x0.55) = 500 Hz. This is the LNRF and the position of the first formant. The next higher modes are 3f0=1500 Hz, and 5f0=2500 Hz. The even modes are missing. The latter two resonant frequencies are the second and third formants.

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Your Answer to Q365.  Sorry, your answer is not correct.  A vowel is formed by passing the glottal wave through the "filter"  of the vocal tract.

Help: Fundamentals of Sound, Sec. 8-C.

Or would you like a HINT?

You should try to work out the answer on your own, but if you insist on reading it the correct answer is here.

Return to Question 365.

 

 

Hint for Question 365:  A vowel is formed by passing the glottal wave through the "filter" of the vocal tract. Voice pitch is determined by the repeat frequency of the glottal wave.
 
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Your Answer to Q365. Congratulations, your answer is correct.

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Correct Answer to Question 365:  The correct answer is f); both a) and c) are correct. For a vowel to be pronounced correctly requires a standard shape of the vocal tract. This shape determines the formants and what quality of sound, that is, which vowel, is heard. Thus a) is correct. However the glottal wave passing through the vocal tract can have any repeat frequency— and it is the repeat frequency that determines the pitch of the voice, high for a child and low for an adult. Even after filtering, the two golttal waves continue to differ, and the one with the higher repeat frequency continues to have, for example, a less dense frequency spectrum. So b) is incorrect. However the envelope of the frequency spectrum is determined by the formants and those have the same relative positions for the same same vowel spoken by two different individuals, so that c) is correct.

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Your Answer to Q367.  Sorry, your answer is not correct. Can you figure out what is wrong with the statement you chose?

Help: Fundamentals of Sound, Chapter 8.

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You should try to work out the answer on your own, but if you insist on reading it the correct answer is here

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Hint for Question 367:  Perhaps you should review Chapter 8 to see the general outline of how a speech sound is formed. .
 
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Your Answer to Q367. Congratulations, your answer is correct.

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Correct Answer to Question 367:  The correct answer is a). A wide-band spectrum does allow one to see the individual glottal pulses on a spectrogram. The frequency corresponding to the voice would be 6/(3xI0-2 s) = 200 Hz, which is reasonable. b) is incorrect since the pitch of a voice would change if the fundamental frequency of the glottal pulses were changed. c) is incorrect because one is usually able to see the formants in either a wide- or narrow-band spectrogram. d) is incorrect because a formant will not of itself show the pitch. One needs to look at the glottal spectrum. e) is incorrect: The artificial larynx produces only a glottal pulse, while the patient's vocal tract would continue to act as a filter to produce the formants.

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Your Answer to Q370.  Sorry, your answer is not correct. Compare each sound with those shown in Chapter 9.

Fundamentals of Sound reference:Chap. 9.

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You should try to work out the answer on your own, but if you insist on reading it the correct answer is here

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Hint for Question 370:  For "stay" look for the fricative followed by the plosive.
 
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Your Answer to Q370. Congratulations, your answer is correct.

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Correct Answer to Question 370:  The correct answer is e) 213 - "stay," "look," "seen." "Stay" starts out with a fricative—the noisy high frequency sound, followed by the blank space of a plosive "t." The next part is the vowel and semi-vowel of "ay". In the vowel-semivowel part, one can see the little bit of movement of the formants. "Seen" also starts with a fricative, but one can see the vowel with its formants following. The ending on "seen" is characteristic of the nasal with the weak second formant. "Look" starts with a semi-vowel and vowel—there is some motion in location of the formants—followed by the silence and noise of the plosive.

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