Abstract: An acoustic board including a front panel formed with a plurality of large openings and small openings, a rear panel having a distance from the front panel, an intermediate panel fitted between the front panel and the rear panel thereby forming a front chamber between the front panel and the intermediate panel and a rear chamber between the intermediate panel and the rear panel and having a plurality of large holes and small holes, and a plurality of sound collecting devices each including a conical hood, a cover, an outer housing and a front silencer, whereby the noise can be effectively isolated from one side to another.

Abstract: This invention relates to an acoustic board and in particular to one which includes a framework, a front panel formed with a plurality of larger openings and smaller openings and fitted on one side of the framework, a rear panel fitted on another side of said framework thereby forming a space between the front panel and the rear panel, a plurality of sound collecting cylinders having an open front end and a closed second end and each fitted within respective larger openings of the front panel and having the open end aligned with the larger openings of the front panel, and a plurality of silencers formed with a plurality of elongated perforations and extended through and supported in an opening provided in the second end of the sound collecting cylinder.