Speech Intelligibility and Reverberation - Sound Demos

The sound files in the table below are a demonstration of the effects of additive noise and reverberation, respectively, on speech intelligibility. The reference signal in the first row (please select the appropriate column for each language) is a clean speech sample, without additional noise or reverberation. (The sentences used here are taken from specific tests - the so-called "matrix tests" - for measuring speech intelligibility. See, e.g., Wagener et al., 2003.) In the second row, a speech shaped, stationary noise signal is added at a signal-to-noise ratio (SNR) that typically yields 50% intelligibility for normal-hearing listeners. The signals in the last last two rows show the effect of two rooms with considerably different reverberation times on speech alone (without an additional noise interferer). Please note that two different sentences are used per language. Using headphones for listening is strongly recommended for correct binaural display.

Wagener, K., Josvassen, J. L., and Ardenkjaer, R. (2003) Design, optimization and evaluation of a Danish sentence test in noise. Int. J. Audiol. 42, 10-17.


  Danish Dutch English French German Polish Swedish
no reverberation (anechoic) Listen
no reverberation (anechoic)
with additional noise
yielding 50% intelligibility
(simulated) class room
(no additional noise)
(simulated) large church
(no additional noise)