Results of sound measurements in the discotheque. The frequency analyzer was placed in the audience. (A) Frequency analysis obtained during "techno" music with a high level at deep frequencies. Gray bars show the mean sound pressure level (SPL) of each frequency analyzed; lines represent the minimal and maximal SPL values, respectively. (B) Continuous increase in loudness. A mean value of 95 dB(A) was established, but peaks of 110-120 dB (A) were found at the beginning of music exposure (22:14 P.M.) that rose to 125- 130 dB(A) at the end of the discotheque visit (0:34 A.M.). Thick line gives the actual noise peak levels; thin line (Leq) shows the energyequivalent level of continuous noise. MV = mean value.