CSD313L_SoundIntensityPressureNarration

The relative measure bel relative relative measure ix

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Unformatted text preview: sound. the Relative Measure - Bel Relative Relative measure – Ix / Ir – Ir = 10-12 watt/m2 – However, Ix / Ir is a quite large number, like 106 – To compress this large value of relative To measure measure Bel = log10(Ix / Ir) – Example: Ix = 10-6 watt/m2 Bel = log10(Ix / Ir) = log10(10-6 / 10-12) = log10(106) = 6 Relative Measure - deciBel Relative deciBel – deciBel (dB) = 10 * Bel = 10 * log10(Ix / Ir) – dB IL = 10 * log10(Ix / Ir) Example 6 – Given a sound Ix at 10--6 watt/m2, how much is dB watt/m how IL? IL? – dB IL = 10 * log10(Ix / Ir) = 10*log10(10-6 / 10-12) = dB 10*log10(106) = 10*6 = 60 dB IL 10*log dB IL - Example dB 13 Given a sound Ix at 10--13 watt/m2, how much is dB watt/m how IL? IL? – dB IL = 10 * log10(Ix / Ir) = 10*log10(10-13 / 10-12) = dB 10*log10(10-1) = 10*(-1) = -10 dB IL 10*log – NOTE, negative value of dB IL means the target sound NOTE, intensity is lower than the reference sound intensity. intensity 12 What if Ix at 10--12 watt/m2, then dB IL = ? watt/m – dB IL = 10 * log10(Ix / Ir) = 10*log10(10-12 / 10-12) = 10*log10(1) = 10*0 = 0 dB IL 10*log – 0 dB IL means this sound has the same intens...
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