Perceived Sound Reduction and why it is used
Perceived sound reduction is how humans experience a decrease in loudness, and a 10-decibel (dB) drop is perceived as the sound being half as loud. This perception is influenced by psychoacoustics, which explains how the human ear and brain interpret sound. While an instrument might measure a specific percentage reduction, the perceived reduction is what matters to our ears. [1, 2, 3, 4]
Perceived vs. measured reduction
- Psychoacoustics: This is the study of how humans perceive sound. It shows that a 10 dB reduction is heard as being roughly half as loud, not 90% quieter. [1, 2, 3]
- Perceptual vs. objective measures: Soundproof window sellers might use a measured 75% noise reduction, which is true by instrument, while also stating a 50% reduction, which can be true depending on the specific noise levels and the human ear's sensitivity. [4]
- The ear's sensitivity: As it gets quieter, the ear becomes more sensitive to noise, so some of the objective reduction is "lost" in perception. [4]
How reduction is achieved
- Sound attenuation: This involves reducing the transfer of sound energy by using materials like soundproofing panels, which can absorb and dampen noise. [5]
- Sound masking: This technique introduces a background noise to make distracting sounds, like conversations, less intelligible and less intrusive. It doesn't remove the sound, but makes it less noticeable and easier to ignore. [6, 7]
Key takeaway
- A 10 dB reduction means the sound is perceived as about half as loud. [1, 2]
- The way we perceive loudness is not linear, which is why a 10 dB drop feels significant, even if the actual percentage of reduction is less extreme. [1, 2, 8]
- Sound masking is an effective way to reduce distractions without physically removing sounds, which is useful in environments where removing the sound source is not an option. [6]
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