Other Definitions
acoustic impedance (dict)
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Acoustic ImpedanceAcoustic impedance ''Z (characteristic impedance or sound impedance) is the ratio of sound pressure p to particle velocity v. Also it is the product of the density of air ρ (rho) and the speed of sound c''. See table: acoustic impedance vs. temperature.
The acoustic impedance Z in Pa·s/m (or, in the equivalent units common before the pascal was added to SI, N·s/m3) is: -
Z = \frac{p}{v} = \frac{J}{v^2} = \frac{p^2}{J} = \rho \cdot c The acoustic impedance (characteristic impedance) of air is Z = 410 Pa·s/m at the temperature 25 C (77 F) or 413 Pa·s/m at 20 C (68 F). C = degree Celsius and F = degree Fahrenheit. p = sound pressure in N/m2 = Pa = pascal
v = particle velocity in m/s
J = sound intensity in W/m2
F = force in N = newton
ρ (rho) = density of air in kg/m3
c = speed of sound (acoustic wave velocity) in m/s Table - Acoustic impedance Z, Speed of sound in air c,
density of air ρ vs. temperature C | colspan="4" align="center" | Impact of temperature | | C | c in m/s | ρ in kg/m | Z in Pa·s/m | | - 10 | 325.4 | 1.341 | 436.5 | | - 5 | 328.5 | 1.316 | 432.4 | | 0 | 331.5 | 1.293 | 428.3 | | + 5 | 334.5 | 1.269 | 424.5 | | + 10 | 337.5 | 1.247 | 420.7 | | + 15 | 340.5 | 1.225 | 417.0 | | + 20 | 343.4 | 1.204 | 413.5 | | + 25 | 346.3 | 1.184 | 410.0 | | + 30 | 349.2 | 1.164 | 406.6 | External link
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