Massloaded

Massloaded is an adjective used in engineering and acoustics to describe a structure, material, or system to which additional mass has been applied in order to increase inertia and modify dynamic properties. Mass loading is commonly employed to lower resonant frequencies, dampen vibrations, and reduce the transmission of sound through a structure. In building acoustics, adding mass to walls, ceilings, and floors increases the surface mass per unit area, improving sound isolation, especially at low frequencies, when paired with proper airtight detailing and, where appropriate, decoupling or damping.

A well-known implementation is mass-loaded vinyl (MLV), a dense flexible sheet used to add mass to surfaces without heavy structural remodeling. MLV comes in varied thicknesses and densities and is installed behind drywall, under floors, or around ducts to improve sound transmission class (STC) and impact isolation. Other forms include cementitious or polymer-based coatings and boards designed to increase mass per area.

Limitations of mass loading include substantial weight, potential installation complexity, and diminishing returns at higher frequencies. It requires careful integration with existing structures, including fastener selection, sealing, and moisture management. Mass loading is most effective as part of a broader acoustic strategy that also includes absorption, sealing, and, where necessary, decoupling. Beyond acoustics, the term can refer to adding mass to sensors or components for calibration or performance tuning, though this usage is less common.