MLV acts as a reflective barrier. The importance is that it contains and blocks the sound from leaving the confines of a space.
When sound waves make contact with a surface, their energy causes vibration. That vibration enlarges and transfers to the air surrounding the outside of a room.
Vibrations travel and transfer easily when the surface is firm like a wall or floor. If the structure were flexible or mobile, it would absorb the energy from the vibrations better and less noise would be transmitted. This is where MLV comes in. Since walls and floors are not typically made of malleable material, MLV acts as a sound proofing barrier within the structure to prevent sound vibrations from leaving the space. Due to MLV’s quality of flexibility, it makes an excellent barrier from vibrations, thus preventing the transmission of sound.
The installation of MLV is very straightforward. However, there are some recommendations for optimal performance.
For best results when installing in walls, it is recommended MLV be placed against the studs, then place drywall over. Although not necessary, it is suggested that MLV be hung in a horizontal manner in order to minimize the number of seams. This method allows for easy caulking or taping per section. Alternatively, MLV can be placed over existing drywall.
For installation in floors, it is always recommended MLV be installed beneath flooring.
For installation on pipes or equipment, simply measure the amount of material needed, cut with a utility knife, then fasten MLV using either tape or clamps.
Sound Transmission Class (or STC) is a test rating of how well a building partition reduces sound. STC is the most common sound reduction measurement which is widely used to rate interior and exterior walls, ceilings, floors, doors, and windows. The STC rating figure roughly reflects the decibel reduction in noise that a barrier can provide. In short, STC gives you an idea of how much sound a structure might stop.
STC is calculated by taking the Transmission Loss (TL) values tested at 16 standard frequencies over the range of 125 Hz to 4000 Hz which are then plotted on a graph. The curve created by data points on this graph are then compared to standard STC reference curves. The rating of the curve from the standard STC reference that matches most closely to the curve from testing is how the STC rating is determined.
STC ratings are the only way to accurately compare noise reduction capabilities between different products.