Psychoacoustic Speech Tests: A Modified Rhyme Test

An attempt has been made to develop and evaluate an intelligibility test that can be used routinely by operational personnel to evaluate the condition of communication systems. The format used is similar in general respects to that described by Fairbanks as a rhyme test. Six lists of fifty monosyllabic words were constructed in such a way as to form fifty ensembles, each composed of six related words. Any given ensemble is characterized by one vowel that is the nucleus of each word; all of the words in a given ensemble either are initiated or terminated by the same consonantal phoneme. The listener is asked to select from each ensemble the word being transmitted. An experiment was performed to determine the general reliability and acceptability of this new test when administered under a wide range of signal-to-noise ratios to U. S. Air Force enlisted personnel. Testing of 18 subjects over a period of 30 days showed that repeated exposure to the materials did not change the average response levels in any appreciable way. Analyses of responses to individual phonetic elements suggest that the test may be useful for diagnostic purposes, as well as for over-all evaluation of communication systems. [This work has been supported by the Decision Sciences Laboratory, Electronic Systems Division, U. S. Air Force.]