Recognition of low-pass filtered words in a noisy and reverberant environment with and without earmuffs.

The effect of earmuffs on the recognition of low-pass filtered Finnish speech test material was investigated by presenting both the unfiltered and filtered words at two speech levels, 60 dB(A) and 85 dB(A) to a group of students with normal hearing. The background noise level (quiet, S/N +10, +5, 0 dB) and reverberation time (2.1 s and 1.6 s) were altered in a multi-purpose hall. Unfiltered words were recognized better without earmuffs in quiet conditions and at S/N +10 and +5 dB. At S/N 0 dB, however, better scores were obtained when earmuffs were used. Filtered words were recognized significantly better without earmuffs at both reverberation times and at all S/N conditions tested. The decrease in the reverberation time improved all the recognition scores essentially.