The effect of infrasonic and very low frequency noise on speech intelligibility

An experiment was performed in which a noise containing frequencies from 10 Hz to 47 Hz was used to mask speech. The behaviour of speech intelligibility with speech presentation level and masking noise level was examined briefly.The infrasonic and low frequency masking noise did reduce the intelligibility of speech. The effect only became significant when the masking noise level was present at levels of 115 dB OASPL or above.