Abstract: A headphone section 10 having microphone elements 14L, 14R for detecting a sound around the user and signal acoustic transducing elements 15L, 15R which function as a sound source for canceling the sound around the user housed in the headphone boxes 13L, 13R and a control circuit section 20 that includes a noise canceling headphone together with the headphone section 10 are separately configured. The control circuit section 20 is adjusted in such a manner that variation can be reduced and predetermined frequency characteristics and gain characteristics are achieved at a predetermined frequency. To the headphone section 10, gain adjusting sections 16L, 16R are equipped.

Abstract: A sound collector which enables users to easily hear a sound from the front of the user's head when mounted on the user's head. The sound collector includes right and left hunger blocks provided at the ends of a headband to be mounted on the user's head, right and left microphone units for collecting an external sound, right and left loud speaker units supported on the right and the left hunger blocks for multiplying the external sound collected by the right and the left microphone units and emitting the amplified sound, and a power source block.

Abstract: A headphone apparatus includes a speaker unit accommodated in an accommodating member of an open-air type, a microphone disposed at a front side of the speaker unit, a circuit arrangement mounted on a circuit board in the speaker unit including a filter for lowering a level of a high frequency component of a signal picked up by the microphone, and a negative feedback loop for feeding back an output of the filter to the speaker unit to thereby lower the level of a low frequency component of circumference noise output from the speaker unit. This headphone apparatus further includes an equalizer having a frequency characteristic substantially opposite to that of the filter, wherein an input audio signal is added to the negative feedback loop through the equalizer and then output from the speaker unit.