Learning Exercise

Vowel acoustics

In this lab, students record vowels and diphthongs, measure Fundamental Frequency, identify F1 and F2 and explain how tongue placement affects them.

Audacity is a free, easy-to-use audio editor and recorder for Windows, Mac OS X, GNU/Linux, and other operating systems.... see more


Lab 6: Vowel Acoustics Vocal acoustics A. Concepts to work with 1. vocal tract as various tubes w/ resonances 2. acoustics of vowels (formants) /α/, /i/ /u/ 3. Spectral analysis reading 4. Waveform reading B. Activity: Create these recordings in Audacity. Use Edit, Preferences, and in the Spectrogram tab, set the FFT to 512 and the Max frequency to 8000 Hz. 1. Record /α/, /i/, /u/ (as in “ha, he, who”) for each lab partner, holding the microphone about 3 inches from your mouth. a. Use the plus button on the left at the upper right on the tool bar to make the timeframe bigger (so you can see hundredths of a msec). Then drag the bottom of the picture down so the waveforms are bigger. Use a central portion of the /α/ to figure out your fundamental frequency. Count the number of repeating waves you see in 1/10th of a msec. Multiply that by 100 to get your Fo. Copy and paste your picture into your lab. Use the minus button in Audacity until you can see all 3 syllables before moving on to the next question. What is your fundamental frequency (Fo)? ________________ b. Toggle to the spectrogram view. Highlight a segment of the /α/, then choose Analyze, Plot Spectrum from the menu at the top. Find the formants; for /α/ it is hard because F1 and F2 are very close together. Norms for females are in parentheses to help you find them. Yours should be a similar frequency. Then do the same for the other 2 vowels. Copy these spectrograms and plots into your lab. Label the formants with a line. Contact a friend and compare your results, including the numbers in your tables. How does tongue placement affect F1? What changes in tongue placement affect F2? /α/ Name F1 (850 Hz) F2 (1220 Hz) /i/ Name F1 (310 Hz) F2 (2790 Hz) /u/ Name F1 (370 Hz) F2 (950 Hz) c. Record a whispered /α/. Change it to a spectrogram. Magnify at least once. Copy and paste it into your lab and put a copy of your spoken /α/ next to it. What are the differences between a whispered /α/ and a spoken /α/? Where are F1 and F2 for the whispered and spoken /α/? Analyze both with a plot spectrum and include those pictures in your lab. 2. Diphthongs: Record /αi/, /jα/. Change it to a spectrogram. Magnify two times. Copy and paste it into your lab. Describe the changes in the formants. Why do they change?

Technical Notes

I have students use Jing or MWSnap to capture the spectrogram images and insert them into the lab.


Using Audacity to record speech, screen capture


vowel acoustics

Learning Objectives

Students will: 1. Measure fundamental frequency 2. Identify F1 and F2 3. Explain how tongue placement affects F1 & F2