Power ratio = 10^(dB/10); amplitude ratio = 10^(dB/20). A +10 dB rise is roughly twice as loud to human ears. Related: note frequency, reverb time.
You enter a decibel value and select a reference standard. The tool applies the standard decibel formulas: power ratio = 10^(dB/10) and amplitude ratio = 10^(dB/20). It then multiplies the reference level by the amplitude ratio to get the absolute physical value. The comparison card subtracts two dB levels and converts the difference to a power ratio and an approximate perceptual multiplier.
Each uses a different reference point. dB SPL references 20 micropascals (the threshold of human hearing). dBV references 1 volt. dBu references 0.775 volts (the voltage that produces 1 mW across 600 ohms). dBm references 1 milliwatt of power.
Decibels measure physical power on a logarithmic scale, not perceived loudness. A 10 dB increase is 10× the power but roughly 2× the perceived loudness. Human hearing is approximately logarithmic, which is why the dB scale exists.
Yes. Negative decibels mean the signal is below the reference level. For example, −6 dB SPL means the sound pressure is about half the reference pressure, well below the threshold of hearing.
It is a rough approximation. True loudness perception depends on frequency (Fletcher-Munson curves), duration, and individual hearing. For critical audio work, use A-weighted measurements and calibrated equipment.
Prolonged exposure above 85 dB SPL can cause hearing damage. Sounds above 120 dB SPL can cause immediate pain, and 140 dB SPL can cause instant permanent damage. Always use hearing protection in loud environments.
Estimate only. Results reflect your inputs and standard formulas. Double-check important decisions independently.