Active sound reduction apparatus and active noise insulation wall having same

An active noise insulation wall, comprising:

• a plurality of rows formed by spacing adjacent rows by a predetermined distance, each of the rows being formed from a plurality of active sound reduction apparatuses, the plurality of active sound reduction apparatus in one row being spaced apart from the plurality of active sound reduction apparatus in an adjacent row, each such apparatus including,
• an active acoustic control cell, disposed on an upper end surface of a noise insulation wall, for controlling a coming noise such that a diffracted sound pressure component of the coming noise at the upper end surface is actively reduced, and
• one sound tube or a plurality of sound tubes of a length which is nearly ¼ of a wavelength or wavelengths of one sound wave or a plurality of sound waves other than a control target frequency of the active acoustic control cell, the one sound tube or the plurality of sound tubes being provided on a side of the active acoustic control cell facing a sound source to be subjected to sound reduction, or on a side of the active acoustic control cell opposite to the sound source, or on both of the sound source side and the opposite side of the active acoustic control cell,
• wherein the plurality of active sound reduction sound apparatuses is disposed in a longitudinal direction of the noise insulation wall.

An active noise insulation wall, comprising:

• a plurality of rows formed by spacing the adjacent rows by a predetermined distance, each of the rows being formed from a plurality of active sound reduction apparatuses, the plurality of active sound reduction apparatus in one row being spaced apart from the plurality of active sound reduction apparatus in an adjacent row, each such apparatus including,
• an active acoustic control cell, disposed on an upper end surface of a noise insulation wall, for controlling a coming noise such that a diffracted sound pressure component of the coming noise at the upper end surface is actively reduced, and
• one acoustic resonator or a plurality of acoustic resonators tuned to a frequency or frequencies other than a control target frequency of the active acoustic control cell in order to decrease a sound pressure at the frequency or frequencies, the one acoustic resonator or the plurality of acoustic resonators being provided on a side of the active acoustic control cell facing a sound source to be subjected to sound reduction, or on a side of the active acoustic control cell opposite to the sound source, or on both of the sound source side and the opposite side of the active acoustic control cell,
• wherein the plurality of active sound reduction apparatuses is disposed in a longitudinal direction of the noise insulation wall.