Acoustic Impedance Calculator Formula

Understand the math behind the acoustic impedance calculator. Each variable explained with a worked example.

Use the Acoustic Impedance Calculator

Formulas Used

Acoustic Impedance

impedance = density * sound_speed

Variables

VariableDescriptionDefault
densityMedium Density(kg/m3)1.225
sound_speedSpeed of Sound(m/s)343

How It Works

Characteristic Acoustic Impedance

Acoustic impedance determines how much sound pressure results from a given particle velocity in a medium.

Formula

Z = rho * c

  • *rho* = medium density (kg/m3)
  • *c* = speed of sound in the medium (m/s)

    • Air: about 415 Rayl. Water: about 1.48 million Rayl. Large impedance mismatches cause strong reflections at boundaries.

    Worked Example

    Air at sea level (rho = 1.225 kg/m3, c = 343 m/s).

    density = 1.225sound_speed = 343
    1. 01Z = rho * c
    2. 02Z = 1.225 * 343
    3. 03Z = 420.2 Rayl

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