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计算声源的声功率和声功率级。
Sound Power Level
100.00 dB
Sound Power Level vs Sound Power
公式
Sound Power Level
Sound power is the total acoustic energy emitted by a source per second, independent of distance or room.
Formula
Lw = 10 log10(W / W0)
Sound power is an intrinsic property of the source. Intensity at distance r in free field: I = W / (4 pi r^2).
计算示例
A loudspeaker emitting 0.01 W.
- 01Lw = 10 log10(0.01 / 1e-12)
- 02Lw = 10 log10(1e10)
- 03Lw = 10 * 10 = 100 dB
- 04Intensity at 1 m = 0.01 / (4 pi) = 7.96e-4 W/m2
常见问题
How does sound power differ from sound pressure level?
Power is the total energy output (property of the source). Pressure level depends on distance and the acoustic environment. Power is measured in watts; SPL in dB re 20 micropascals.
How is sound power measured?
In a reverberation room (comparing with a reference source) or an anechoic chamber (integrating intensity over a surface enclosing the source).
What is a typical sound power for speech?
Normal speech produces about 10 to 50 microwatts (about 70 to 77 dB Lw). Shouting can reach 1 milliwatt.
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