Mass Loaded Vinyl (MLV) is a versatile and effective soundproofing material for windows, made out of PVC and vinyl by using a weighty substance which include barium sulphate or calcium carbonate. To fight airborne sound, the aim is to reduce the gaps and cracks through which sound waves can penetrate. https://ottlite55432.mybuzzblog.com/6351919/5-simple-techniques-for-acoustic-4sash-windows