Acoustical Treatments on Ventilation Ducts through Walls: Experimental Results and Novel Models

Sound reduction is complex to estimate for acoustical treatments on ventilation ducts through walls. Various are available ducts, including internal lining (absorption along the inner perimeter), external lagging (external sound insulation), silencer, and suspended ceilings. Previous studies have examined how silencers affect transmission of ducts. However, there few theories predict effect in combination with total affected. This article aims investigate different develop theoretical models when stone wool used reduce flanking via surface area Theoretical developed compared measurement data. Measurements theory generally good agreement over third-octave band range 100–5000 Hz. The clarify that distance closest wall has main impact a combined system duct. Suspended ceilings found be enough as certain combinations seems only effective solution offices schools large duct passes high reduction.