The effectiveness of electronic earmuffs is improved by incorporating a mechanism which causes the middle ear muscles to contract before an intense sound is generated. This contraction is achieved by incorporating a wireless receiver into the earmuff. Immediately prior to the generation of the intense sound, the wireless receiver receives a signal which causes it to generate a loud, non-damaging sound in a loudspeaker in the earmuff. The received signal is generated by a radio frequency transmitter that is activated immediately prior to the activation of the mechanism producing the intense sound. The non-damaging loud sound from the loudspeaker causes the middle ear muscles to contract (this is a natural reflex of the ear). The intense sound is received outside the earmuff before the reflex contraction of the middle ear muscles has been relaxed.
A device and a method for preventing damage to hearing which may result from activation of vehicle occupant restraint systems operate using a source of sound for producing a primary sound event having a sound pressure level non-injurious to hearing. The sound pressure level is, however, sufficient to trigger the so-called acoustic reflex of the human ear which has the effect that the ear's sensitivity is reduced when exposed to high sound pressure levels and the subsequent sound event has only a fraction of the negative effects of the primary sound event on the internal ear. The primary sound event needs only be triggered sufficiently shortly in time before the secondary sound event which occurs on activation of the restraint system and features a sound pressure level injurious to hearing.
