Perceived Loudness Doubling
A 10 dB increase is heard as roughly twice as loud.
Formula
Variables
Example
60 dB to 70 dB ≈ twice as loud
How it works
Sound intensity is measured on a logarithmic decibel scale, so equal jumps in dB do not correspond to equal jumps in physical power. For typical listening, an increase of about 10 dB is usually perceived as roughly a doubling of loudness, even though the sound power has increased by a factor of 10. This rule of thumb comes from human hearing being much less sensitive to percentage changes at higher volumes than a linear scale would suggest.
When to use it
Use this when comparing two sound levels and you want a quick estimate of whether one will seem about twice as loud as the other. It is common in acoustics, audio engineering, and everyday noise comparisons.
Worked example, step by step
A concert monitor reads 72 dB, and later it reads 82 dB. Change in level: ΔL = 82 dB - 72 dB = 10 dB Apply the rule: a 10 dB increase is heard as about twice as loud Conclusion: 82 dB sounds roughly 2 times as loud as 72 dB
Common mistakes to avoid
- Thinking a 10 dB increase means the sound power only doubles; it actually increases by a factor of 10
- Using the rule for exact judgments in every situation; perceived loudness depends on frequency, context, and listener
- Confusing loudness with intensity or amplitude, which are physical measures rather than the ear's perception
Did You Know?
Perceived loudness follows a power law — our ears compress an enormous range of intensities into a comfortable scale.
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