Noise control is an active or passive means of reducing sound emissions, often incentivised by personal comfort, environmental considerations or legal compliance. Practical and efficient noise control is wholly reliant on an accurate diagnosis of what is causing the noise, which first involves finding the source of noise. Once the source of noise has been found, the focus is reducing the noise at source by engineering means.

Noise Absorption Sound absorbers are soft, porous, open-celled materials such as foam sheets or fiberglass blankets and baffles that reduce the reflection of sound waves. Their sound absorption efficiency is rated by a “NRC” number – Noice Reduction Coefficient*. The HIGHER the NRC rating, the more EFFICIENT the product is at absorbing noise.

Noise Absorption
Sound absorbers are soft, porous, open-celled materials such as foam sheets or fiberglass blankets and baffles that reduce the reflection of sound waves. Their sound absorption efficiency is rated by a “NRC” number – Noice Reduction Coefficient*. The HIGHER the NRC rating, the more EFFICIENT the product is at absorbing noise.

Quoted from https://allnoisecontrol.com/glossary/index.cfm:

Acoustic Glossary of Terms and Definitions for soundproofing and noise control research, products and materials

Question:
STC means how well the product stops or blocks sound from getting into or out of the room. Is noise absorption the level of noise that is generated from within the area that bounces off the material/wall? I want to make sure I understand the difference between them. Also, which one is more important to people?

Another post by a visitor that will be sure to help anyone in shared commercial spaces with noise coming in from adjoined spaces which is a typical situation found in commercial and retail spaces

We are a massage therapy business and need to block the noise coming through the walls and across the drop ceiling from the business next door, which has loud screaming children and music.
Which would be the most effective way to block the noise, on their side of the wall or on our walls? Both sides of ceilings?
We need absoulte quiet for our business.
Any suggestions would be most appreciated!?
Thank you,?

Question:
I need to reduce the noise level reaching a residence located approximately 150 feet from an industrial metal stamping plant. The plant external wall is standard cement block. Would it be feasible to fill the cement block cores with a sound absorbing foam that could be sprayed in as a semi-liquid? I also am interested in applying material inside this plant wall to further reduce the external noise situation. What are the range of choices vs. cost?
Thanks for any help you can provide ….
Larry

What options are there for blocking noise from i/o boat motors

Marine products need to be produced to withstand the harsh marine environments. Our
best product would be Vibration Damping & Noise Tiles . While these are widely used underneath equipment to reduce equipment vibration, they can also be cut and layered inside compartments and tucked into tight spots to deal with engine noise and the added benefit of helping vibrations where equipment may be touching or close to touching. A similair product and just as durable is our mass loaded vinyl barrier. This can be affixed to the compartment and areas surrounding