Headphones; Megaphones; Microphones; Sonars; Acoustic alarms; Acoustic couplers; Acoustic separation units; Acoustic sound alarms; Apparatus for wireless transmission of acoustic information; Audio-receivers and video-receivers; Audio equaliser apparatus; Audio mixers; Computer chips; Conductive silicone packing for electro-magnetic interference; Data processing apparatus; Digital sound processors; Equalizers being audio apparatus; Filters for radio interference suppression; Humanoid robots with artificial intelligence; Integrated circuits; Silicon chips; Sound equalizers and crossovers; Sound recording apparatus; Sound transmitting apparatus; Surveying machines and instruments; Telephone receivers