LAB 13: Speech Intelligibility and Confusion Matrices

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The main purpose of this laboratory is to examine two methods of assessing the intelligibility of speech passed through a communication channel.

Here are the resources that you will need:

Lab Handout (PDF)

Audio for the Listening Tests

In this lab, you will participate as a subject in two types of intelligibility tests:

• Consonant-vowel (CV) nonsense syllables with 10 dB, 5 dB and 0 dB signal-to-noise ratios (SNRs).
• Sentences in noise (Spin test) with 10 dB and 0 dB signal-to-babble ratios (SBRs).

The stimuli will be presented on audio tape during class. If you do not attend the class, the audio is available on the Lab Database page.

A third type of test is available, although it is not presented in class:

• Consonant-vowel-consonant (CVC) nonsense syllables with a 0 dB SNR.

The audio for this test is available on the Lab Database page.

The Tools

• Paper and pencil
• Response sheets: CV response sheet (PDF) (3 copies), Spin test response sheet (PDF) (2 copies)
• Answers to the tests: CV answers (PDF), Spin test 0dB answers (PDF), Spin test 10dB answers (PDF)
• If you choose to do the CVC test, you will need: CVC response sheet (PDF) (1 copy), and CVC answers (PDF)

Reference Readings

Miller, G. A., and P. E. Nicely. "Analysis of perceptual confusions among some English consonants." J Acoust Soc Am 27 (1955): 338-352.

Kalikow, D. N., K. N. Stevens, and L. L. Elliot. "Development of a test of speech intelligibility in noise using sentence materials with controlled word predictability." J Acoust Soc Am 61 (1977): 1337-1351.