<p>A sound reproducing device suitable for use with a headphone of the open-air type in noisy environment. The frequency band of sounds leaking out when the headphone is put on is measured in advance, and the leakage from the headphone is controlled by switching a filter for attenuating the leakage frequency band when the headphone is being put on. Moreover, noise frequency characteristics are measured in advance, a low frequency band is reinforced to correspond to the above characteristics, and operation of the filter is changed over to attenuate the high frequency band that includes the above sound leakage frequency band.</p>
