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Sound System Design Equations

Civil Engineering Design

Sound Design Equations

Sound Power (W) - the amount of power a source converts to sound in watts.

Sound Power Level (LW) - a logarithmic comparison of sound power output by a source to a reference sound source, W₀ = (10 ^-12 watt).

L_W = 10 log ₁₀(W/W₀ ) dB

Sound Pressure (P) - pressure associated with sound output from a source. Sound pressure is what the human ear reacts to.

Sound Pressure Level (Lp) - a logarithmic comparison of sound pressure output by a source to a reference sound source, P ₀ (2 x 10^-5 Pa).

Lp = 20 log ₁₀(P/P₀) dB

Even though sound power level and sound pressure level are both expressed in dB, There is not a direct conversion between Sound power level and sound pressure level. A constant sound power output will result in significantly different sound pressures and sound pressure levels when the source is placed in different environments.

Related:

• Acoustic Sound Pressure Level Table
• Acoustic Definitions and Terms