A Decibel (dB) Calculator helps engineers, sound technicians, and researchers measure the ratio of power or intensity between two signals using the logarithmic 分贝标度。 这常用在 audio engineering, telecommunications, electronics, and acoustics to assess sound levels, signal strength, and noise levels.
- 分贝标度 is logarithmic, meaning it measures differences 成倍 rather than linearly. This makes it useful for evaluating loudness levels, amplifier gains, and signal 衰减, where small changes in power or amplitude can result in significant perceived differences.
Formula for Decibel Calculator
- decibel formula depends on whether you are calculating a 功率比 或 amplitude (intensity) ratio:
对于 功率比:
dB = 10 × log₁₀(P₂ / P₁)
对于 intensity or amplitude ratio:
dB = 20 × log₁₀(A₂ / A₁)
地点：
P₂ / P₁ = Power ratio (final power / reference power)
A₂ / A₁ = Amplitude ratio (final amplitude / reference amplitude)
log₁₀ = Logarithm to base 10
- power ratio formula is used when measuring changes in energy or signal strength，而 amplitude ratio formula 适用于 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) | 分贝 (dB) | 应用程序 |
|---|---|---|---|
| 1 | 1 | 0分贝 | No change in power |
| 2 | 1.41 | 3分贝 | Slight increase in sound |
| 10 | 3.16 | 10分贝 | Doubling of perceived loudness |
| 100 | 10 | 20分贝 | Strong audio boost |
| 1,000 | 31.62 | 30分贝 | Loud noise level |
| 1,000,000 | 1,000 | 60分贝 | Typical conversation |
| 10,000,000 | 10,000 | 80分贝 | 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 功率 在 5 瓦至 50 瓦. 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分贝
这意味着 power has increased by 10 decibels， 进行中 声音大一倍 in terms of human perception.
最常见的常见问题解答
A decibel measures the relative intensity of a signal, sound, or power ratio using a 对数刻度。 它用于 audio levels, radio signals, electronic circuits, and environmental noise measurement.
The decibel scale is logarithmic because human hearing and signal amplification 响应 non-linearly。 这允许更精确 测量 of loudness, gain, and attenuation, where small changes in power can result in significant perceptual differences.
A 3 dB increase doubles the 功率 but results in a small perceived loudness change。 一个 10 dB increase makes the sound 声音大一倍 to the human ear, even though it requires 10 times the power.