A Decibel (dB) Calculator helps engineers, sound technicians, and researchers measure the ratio of power or intensity between two signals using the logarithmic デシベルスケール. This is commonly used in audio engineering, telecommunications, electronics, and acoustics to assess sound levels, signal strength, and noise levels.
この デシベルスケール is logarithmic, meaning it measures differences 指数関数的に rather than linearly. This makes it useful for evaluating loudness levels, amplifier gains, and signal 減衰, where small changes in power or amplitude can result in significant perceived differences.
Formula for Decibel Calculator
この decibel formula depends on whether you are calculating a 電力比 または amplitude (intensity) ratio:
電力比:
dB = 10 × log₁₀(P₂ / P₁)
intensity or amplitude ratio:
dB = 20 × log₁₀(A₂ / A₁)
どこ：
P₂ / P₁ = Power ratio (final power / reference power)
A₂ / A₁ = Amplitude ratio (final amplitude / reference amplitude)
log₁₀ = Logarithm to base 10
この power ratio formula is used when measuring changes in energy or signal strength、一方、 amplitude ratio formula に適用されます sound waves, voltage, or current levels.
Decibel Conversion Reference Table
To simplify decibel calculations, the following table provides common dB values for different power and amplitude ratios.
| Power Ratio (P₂/P₁) | Amplitude Ratio (A₂/A₁) | デシベル (dB) | 申し込み |
|---|---|---|---|
| 1 | 1 | 0 dB | No change in power |
| 2 | 1.41 | 3 dB | Slight increase in sound |
| 10 | 3.16 | 10 dB | Doubling of perceived loudness |
| 100 | 10 | 20 dB | Strong audio boost |
| 1,000 | 31.62 | 30 dB | Loud noise level |
| 1,000,000 | 1,000 | 60 dB | Typical conversation |
| 10,000,000 | 10,000 | 80 dB | Loud traffic noise |
This table helps audio engineers, sound designers, and electronics professionals estimate signal amplification, sound loudness, and transmission loss without complex calculations.
Example of Decibel Calculator
A speaker system increases the 電力 from 5ワットから50ワット. The decibel increase can be calculated as follows:
Step 1: Apply the Power Ratio Formula
dB = 10 × log₁₀(50 / 5)
Step 2: Compute the Logarithm
dB = 10 × log₁₀(10)
Step 3: Compute the Result
dB = 10 dB
これはつまり power has increased by 10 decibelsそれを作る twice as loud in terms of human perception.
最も一般的な FAQ
A decibel measures the relative intensity of a signal, sound, or power ratio using a 対数スケール。 それに使用されます audio levels, radio signals, electronic circuits, and environmental noise measurement.
The decibel scale is logarithmic because human hearing and signal amplification 対応 non-linearly. This allows for more precise 測定結果 of loudness, gain, and attenuation, where small changes in power can result in significant perceptual differences.
A 3 dB increase doubles the 電力 but results in a small perceived loudness change。 A 10 dB increase makes the sound twice as loud to the human ear, even though it requires 10 times the power.