Acoustical Aspects of Cocktail Parties

The signal-to-noise ratio in typical cocktail-party situations has been calculated and compared with the masked speech reception threshold for sentences. For the free-field condition (no ceiling) the sound level of the voice babble of all competing talkers is only about 2 dB below the limit for satisfactory understanding of the near-by talker one is listening to. In view of smallness of this margin and the unfavourable effect of ambient noise on the vocal output, the intensity of the noise reflected by the ceiling and the walls should not exceed the intensity of the free-field noise. The sound-absorption coefficients of the walls and the ceiling required to meet this condition are given. Since such measures are insufficient for hearing-impaired people (main category: elderly people with presbyacusis), rooms used by them for social gatherings should be highly sound-absorbent.