Acoustic work is a mass and absorption problem. Machinery noise needs an enclosure with mass on the outside and absorption on the inside; a room needs absorption on the reflective surfaces; a duct needs lining that will not shed fibre into the airstream. We specify all three, and we say which one your problem is before quoting.
Materials run from density-graded rockwool and glass wool through open-cell acoustic sheet to mass-loaded vinyl barrier, finished in perforated GI or aluminium sheet, glass cloth or fabric depending on whether the space is a plant room or an auditorium.
