When designing a soundproof space, you will need to keep a few measurements in mind, such as the Weighted Sound Reduction Index.
What is Weighted Sound Reduction Index and how is it used?
The Weighted Sound Reduction Index (Rw) is a rating to measure and indicate how effective a soundproofing material or system is. This rating is expressed in decibels (dB).
As you can see in the table below, the higher the Rw rating, the better the sound insulation.
For example, according to the figure, at 30 Rw some speech will be intelligible; however, at 48 Rw, loud speech will be audible but unable to be deciphered.
What is Rw + Ctr?
When designing a space and considering its acoustics, you may also see the rating Rw + Ctr.
The Ctr is an adjustment factor for low-frequency noise, because in some cases the Rw rating does not account for all noises (think low-frequency bass noise generated from home theatre or sound systems.)
The low-frequency sound correction factor (Ctr) is always a negative number, which means the Rw value will always be greater than the Rw + Ctr figure.
The Rw + Ctr performance figure is determined by the material properties used and includes factors such as weight, stiffness, thickness and type of cavity insulation.
What acoustic rating should I look for when trying to reduce sound?
So, if you’re looking for a wall system that is effective at reducing sound transmission, you will need to aim for a high Rw rating and a high Rw + Ctr rating.
Also remember that some buildings require a minimum Rw + Ctr value to be achieved.
Bris Aluminium products and achieving desired Rw
When you’re selecting Bris Aluminium partitions for your project and you want to achieve a certain level of sound insulation, remember it’s the combination of materials that gives you acoustic performance and soundproofing.
So always consider the range of other materials you will need to get your desired rating, such as plasterboard, soundproofing glues and seals.
Reach out to us if you have questions about our products and acoustic ratings.
