Noise Reduction Coefficient Calculator

Formula

To calculate the Noise Reduction Coefficient:

\[ NRC = \frac{\alpha_1 + \alpha_2 + \alpha_3 + \alpha_4}{4} \]

Where:

\(NRC\) is the Noise Reduction Coefficient
\(\alpha_1\) is the absorption coefficient at 250 Hz
\(\alpha_2\) is the absorption coefficient at 500 Hz
\(\alpha_3\) is the absorption coefficient at 1000 Hz
\(\alpha_4\) is the absorption coefficient at 2000 Hz

What is Noise Reduction Coefficient?

The Noise Reduction Coefficient (NRC) is a scalar representation of the amount of sound energy absorbed upon striking a particular surface. It is an average rating of how much sound an acoustic product can absorb. NRC is used to rate the effectiveness of soundproofing materials, with higher values indicating better sound absorption. It is particularly useful in environments where controlling noise levels is crucial, such as recording studios, theaters, and offices.

Example Calculation 1

Let's assume the following values:

Absorption Coefficient at 250 Hz (\(\alpha_1\)) = 0.75
Absorption Coefficient at 500 Hz (\(\alpha_2\)) = 0.80
Absorption Coefficient at 1000 Hz (\(\alpha_3\)) = 0.85
Absorption Coefficient at 2000 Hz (\(\alpha_4\)) = 0.90

Using the formula:

\[ NRC = \frac{0.75 + 0.80 + 0.85 + 0.90}{4} = 0.83 \]

The Noise Reduction Coefficient is 0.83.

Example Calculation 2

Let's assume the following values:

Absorption Coefficient at 250 Hz (\(\alpha_1\)) = 0.60
Absorption Coefficient at 500 Hz (\(\alpha_2\)) = 0.65
Absorption Coefficient at 1000 Hz (\(\alpha_3\)) = 0.70
Absorption Coefficient at 2000 Hz (\(\alpha_4\)) = 0.75

Using the formula:

\[ NRC = \frac{0.60 + 0.65 + 0.70 + 0.75}{4} = 0.68 \]

The Noise Reduction Coefficient is 0.68.