A run-safe filter system is provided for confirming installation of a qualified filter element in a housing. The at least one transparent portion is made of one or more materials substantially transparent for light of at least a specific spectral range, referred to as transparent materials, and the at least one blocking portion is made of one or more materials substantially non-transparent for light of the specific spectral range, referred to as non-transparent materials. The motorized clasping mechanism further comprises a rotator mechanism configured to rotate the motorized clasping mechanism in the first direction about the axis. The ultrasound-to-audio-sound conversion in the confined volume of the inner ear appears to be constant pressure, as opposed to constant velocity, such that all frequencies of the audio bandwidth are produced with comparable sound intensity.