A shaped acoustic foam insert for use in improving the performance of circumaural hearing protectors is described. A foam block having a cross-section and shape is adapted to occupy the entire interior volume of an earcup of a circumaural hearing protector. The insert has no folds or open acoustic cavities....http://www.google.es/patents/US20050126845?utm_source=gb-gplus-sharePatente US20050126845 - Attenuating foam insert and method for manufacture
Attenuating foam insert and method for manufacture
