Floor impact noise suppressor in a multi-storied building

A floor impact noise suppressor for reducing propagation of floor impact noises, having a sound wave frequency of not more than about 500 Hz, generated in an upper story to a lower story in a multi-storied building, comprising:

• a reference sensor for detecting a floor impact noise generated in the upper story and converting it to an electric signal, said reference sensor being disposed in a periphery of a floor of the upper story or in any place from a bottom of the floor of the upper story to a bottom surface of a ceiling of the lower story;
• a speaker for emitting a sound wave for suppressing the floor impact noise, said speaker being disposed at a position lower than that where said reference sensor is disposed;
• an error sensor for detecting an interference sound caused by interference between the floor impact noise and the sound wave emitted from said speaker and converting it to an electric signal, said error sensor being disposed inside a room in the lower story;
• means for converting any signal having a low frequency of not more than 200 Hz among the electric signals each transmitted from said reference sensor and error sensor to a digital signal and transmitting it to a controlling means;
• a controlling means for computing, according to an adaptive control based on the signal transmitted from said converting means, a driving signal for emitting a sound wave having a phase reverse to that of said floor impact noise and also having a waveform with the same amplitude as that of said impact noise from said speaker;
• and
• means for converting said driving signal to an analog signal and transmitting it to said speaker.