Homework #4: Speech Acoustics
Department of Linguistics
1. Fundamental frequency I. Download this sound file. Open it up in Wavesurfer 1.8.5, which you can obtain here. For hints on using Wavesurfer, visit here.
a. Pick some interval of time, and count all the vocal cord vibrations that occurred in it. Specify the length of your interval in second (you can read this off the bottom of the screen in Wavesurfer).
b. Use the numbers you just obtain to calculate the pitch in hertz. Show your work.
c. Calculate the period (time needed for one vocal cord vibration). Show your work.
2. Fundamental frequency II.
Answer questions a-b-c above for this sound file.
3. Pitch contours
a. Does the following waveform show rising pitch or falling pitch? Explain your answer briefly.
b. Does the following spectrogram show rising pitch or falling pitch? Explain your answer briefly. Hint: re-read Rogers, p. 158.
2. Aspiration and vowel length.
Listen to these waveforms: A Nye spot B. nice pot (Nye is the name of one of the counties of Nevada.)
You can hear the waveforms here and here (but I'm not telling which order they occur in!).
Which of these figures is the waveform for A, and which for B? Justify your answer.
3. Intonation. Listen to these two wave forms: A B.
Which of these figures is the pitch track (displaying frequency) for A, and which for B? Justify your answer. Note that each pitch track shows a mini version of the waveform above it.
You could answer this question by downloading the waveforms and pitch-tracking them. But if you do this, keep it a secret! We're looking for answers based on intonation patterns.
4. Vowel Formants. Below are displayed spectrograms are of me saying seven vowels. These vowels are (not in this order):
The vowels sound like this:
[open o (backwards c)]
Download the waveforms to your desktop. Open them one by one in Wavesurfer. I suggest you right-click on an image, click Apply configuration, then Speech Analysis.
If you used the Speech Analysis configuration these will have nice little colored lines in the center of each formant. And, at the bottom of the screen, the last four numbers will be the lowest four formant frequencies (F1, F2, F3, F4).
Measure F1 and F2 of each vowel and write down your answer as a table, like this:
5. Plotting Vowels on a Chart
Print out this chart (click on it to bring up a full-screen copy, then print) and plot the values on it, labeling each point for what vowel it is. If you've done everything correctly, it will look like an IPA vowel chart.
6. Using formant transitions to determine place of articulation
In the following three spectrograms, the consonant is either [b], [d], or [g]. The vowel on either side of the consonant is a schwa. Determine which spectrogram has which consonant. Hint: compare these with the spectrograms in Fig. 8.13 of your textbook.
You can hear the sounds here, but not necessarily in the same order as the spectrograms: [b] [d] [g]
8. Sibilant Fricatives
In this spectrogram, the vowels are all [a]. One fricative is [s], the other is . State which fricative came first. Also, explain how you know. Note that the vertical axis is shown going all the way up to 8000 Hz, to help show the fricatives' full spectrum. A hint appears in Chapter 8 of Rogers.
9. Spectrogram Reading
Read both spectrograms. This box says what they say. In prose, justify each of the four two-way choices you have to make.
Rogers has several hints for solving this one. Going from left to right through the spectrogram, the hints are on pp. 163, 152, 78, 162, and 160.
Last updated February 24, 2012