*Acoustical Systems Flashcards
What does transmission loss and noise reduction focus on?
preventing noise from transmitting from one space to another or between spaces
What does sound absorption focus on?
reduces noise within a space to minimize reflections, reverberation and improve speech clarity or privacy
What is STC and what does it rate?
Sound Transmission Class
This is a rating for interior walls.
describes how well a wall assembly reduces airborne sound passage between one side to the other.
The higher the rating the greater the sound isolation.
What is the best way to prevent sound transmission between spaces?
A slab-to-slab partition.
Sound batting can also be added to increase the acoustic qualities, and all penetrations must be sealed.
What is IIC and what does it rate?
Impact Insulation Class
rates how well a floor-ceiling assembly reduces structure-borne sound transmission to the room below.
Impact sound can be reduced by avoiding hard surface flooring using resilient underlayments, furring, or carpeting.
What do NRC and SAC relate to?
Room acoustics
What is NRC and what does it measure?
Noise Reduction Coefficient
measures the ability of a wall or ceiling to absorb airborne sound
What is AC and what does it measure?
Articulation Class
measure of the finished ceiling’s absorption and reflection of sound, but specifically affects speech clarity in an open office environment.
What is CAC and what does it measure?
Ceiling Attenuation Class
is a ceiling system’s ability to reduce sound transmission (not absorption) from one room to another when the rooms share the same plenum space.
Measured in decibles
What is sound masking?
Sound masking systems can provide a low level of background sound specifically engineered to increase speech privacy.
A system of speakers installed in the open ceiling or plenum creates just enough sound to cover up or reduce the disruption of distracting noises.
What are resilient channels?
Resilient channels improve the acoustical properties of a wall by separating the wall’s structure from its surface material. They make the wall less stiff, inhibiting the transfer of vibrations through to the other side.
The absorption of material is defined by the ratio of the sound intensity absorbed by the material to the total intensity reaching the material. What is this called?
coefficient of absorption
Materials with a coefficient of absorption below 0.2 are reflective.
Materials with a coefficient of absorption above 0.2 are sound absorbing.
