A Speech Intelligibility Testing System for Evaluation of Communication- and Hearing Protection Devices

A testing system for speech intelligibility in a noisy environment was developed and as a first case for testing, hearing protectors with one-way communication possibili-ties were chosen. The use of such devices leads to the question of the signal exposure needed for successful communications. By the use of Just-Follow-Conversationmeth-ods, speech-Bekesy and an Ascending method, a value of signal exposure required for signal intelligibility was determined for a population of 12 subjects. This value was then compared to values acquired from a Hearing In Noise Test for the same product. Using standardized H, M and L filtered pink noise the test was conducted using speech signals in form of audiobooks to minimize the effect of learning. Com-parisons of results using a statistical pairwise T-test suggest that the three methods make successful distinction between H-type noise but the methods do not succeed in distinguishing between M- and L-noise, which calls for further investigations int