Soundproofing 101 | 5 Elements of Soundproofing
Soundproofing is reducing the sound pressure between the source of noise generated and the receiver of the sound or reduction in auditory perception of sound pressure. Sound isolation works the same, both ways, there is no difference in approach to keeping sound in or out.
There are 5 elements in sound reduction (Absorption, Damping, Decoupling, Distance and Mass) The “Absorption” aspect in soundproofing should not be confused with Sound Absorbing Panels used in acoustic treatments. “Absorption” in this sense only refers to reducing a resonating frequency in a cavity by installing insulation between walls, ceilings or floors. Acoustic Panels can play a role in a treatment only after walls or ceilings have been soundproofed, reducing the amplified reflection in the source room.
Damping: When Damping a wall , we are aiding in the effectiveness of decoupling, mass, and absorption materials. Think of a wine glass ringing out, if you were to place a crumpled napkin in the glass or wrap the glass with a wet napkin, the resonating sound within the glass will change significantly. Use of Sound Absorption adhesives (Green Glue), Use of Mass Loaded Vinyl or other sound deadening materials to reduce vibration on impact noise.
Decoupling: Separation between sheetrock and studs/joists. Use of Resilient Channel, Sound Isolation Clips, Rubber Pads to minimize impact vibration.
Distance: Sound waves spread out with distance, lessening the sound intensity from the source to the receiver.
Mass: Adding dense materials to a soundproofing treatment in order to stop sound waves from exiting a source wall, ceiling or floor. Use of Mass Loaded Vinyl, QuietRock, Plywood, MDF, Concrete, Rubber… Different materials reduce sound within different frequency range. Use of multiple layers of materials is essential to the success in any treatment.
Most common problems reducing noise between offices are duct work, drop ceilings, walls above drop ceilings that are unfinished and only framed to the drop ceiling, leaving a gap above the wall where sound can transfer from one office to the next. Other issues are speech intelligibility in conference rooms due to reflection or echo in the room. Acoustic Panels being installed strategically can help reduce echo and improve speech clarity.
Larger spaces require heavier acoustic treatment. Echo, reflection, and reverberation can be an issue with higher ceilings, large windows, flat surfaces, etc. Large machinery, HVAC systems, elevators, pumps… produce lower resonating frequencies which require spring loaded isolation mounts, sound deadening materials, added mass to walls and ceilings to prevent vibrations from transferring to the larger rooms where these frequencies can reflect and cause major issues in the work space.
When sound proofing a room in a apartment, we are trying to keep noise out from noisy neighbors, impact noise from ceilings, street traffic from windows.. All of which require different levels of treatment, rarely corrected with acoustic panels or acoustic foam. Window noiseproofing requires sealing the framing of windows, we may replace windows, or install an addition window. Noisy neighbors often involve adding insulation, mass and decoupling the walls or ceiling, sound deadening materials. We may suggest installing heavier solid core doors, weather stripping around the perimeter of the doors, tighter precision door framing..
ROOM WITHIN A ROOM (RWAR)
Creating a large air-gap between the outside wall and inside wall in combination with decoupling the drywall from joists and studs is recommended for reducing sound transfer from exterior noise. This works both ways keeping sound in and out. Most commonly used in a recording studio, this technique has shown great results apartments.
SOUND DEADENING MATERIAL
Several factors come into play when using different sound deadening material, acoustic foam for instance, we are looking at the thickness, cell size, shape, density.. Density in all material is what determines the true effectiveness in any given treatment. Resonant absorbers are a certain density and thickness based on specific frequency range being reduced.