Soundproofing vs Acoustic treatment! STC vs NRC ratings!

Updated: Dec 10, 2020

Basic things you need to know about the difference between soundproofing and acoustic treatment before consulting suppliers.


Soundproofing vs Acoustic treatment! STC vs NRC ratings!

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How to differentiate Soundproofing VS Acoustic treatment?


“Soundproofing and Acoustic Treatment are often mistakenly likened. I was once guilty of equalising them as well, but not until I found out their differences. How about you? Do you make that mistake too?”

What is Soundproofing?


Soundproofing is also called sound isolation. It simply means to prevent sound from escaping the room as well as hindering outside sound from entering the room. The treatment for soundproofing involves construction of soundproof walls, doors, partitions, ceilings, floorings, etc. In the case of soundproofing a wall, an additional wall is built on top of the existing wall so as to create an air gap that will provide sound insulation.


What is STC?

Stands for Sound Transmission Class


When we are talking about soundproofing materials, we often come across this term called ‘STC’. Some suppliers may tell you that most normal doors are only rated at STC 28 and the soundproof doors that they are offering are rated at STC 40. So, what does STC stand for? What does it mean to have a higher STC rating?


The HIGHER it is, the more sound it blocks!


STC stands for Sound Transmission Class. It is a measurement used to calculate how successful a soundproofing material is in reducing the transmission of sound between rooms. It is simply measuring how much a wall can block sound from travelling to the other side of the room. The higher the STC rating, the higher success the material possesses to block sound at the most common frequencies.

What is Acoustic Treatment?


Unlike soundproofing, acoustic treatment is not to prevent sound from leaking in or out of the room but rather to control the sound quality produced by any source of sound within the room. Most acoustic treatments will absorb sound waves and hence refine the sound within the space, producing a better sonic experience for the listeners. Thus, acoustic treatment will improve the clarity of the sound that travels within the room by reducing echoes and reverberation in the room. The treatment for this will require the cladding of existing walls with acoustic panels. This application is effective for recording studios, listening rooms, churches, lecture halls, offices, restaurants and places that need critical listening.


What is NRC?

Stands for Noise Reduction Coefficient


We will eventually run into the term called ‘NRC’ when we are dealing with acoustic products. It is an average rating given to an acoustic product to measure how much sound it can absorb. When some suppliers inform you that they have these acoustics panels that contain a 1-inch fiberglass insulation and possess an NRC of 0.75, do not panic!


The HIGHER the NRC rating, the better the product in absorbing the sound within the room!


Since NRC is measured on a scale from 0 to 1, ‘0’ means that the product absorbs zero sound and ‘1’ indicates that it absorbs all sound. So, NRC of 0.75 simply indicates that the acoustic panels are good enough at absorbing echoes and reverberation in the room.



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References:

Gik Acoustics (website)

Vocal Booth To Go (website)

Audimute (website)