1. What is Acoustic Impedance?

Acoustic impedance (Z) is a physical property of a medium that characterizes how much sound pressure is generated by a given vibration at a particular frequency. It's defined as the product of the density of the medium (ρ) and the speed of sound in that medium (c).

2. How Does the Calculator Work?

The calculator uses the acoustic impedance equation:

Where:

• \( Z \) — Acoustic impedance (Pa·s/m)
• \( \rho \) — Density of the medium (kg/m³)
• \( c \) — Speed of sound in the medium (m/s)

Explanation: The equation shows that acoustic impedance increases with both the density of the material and the speed at which sound travels through it.

3. Importance of Acoustic Impedance

Details: Acoustic impedance is crucial in ultrasound imaging, sonar technology, and noise control applications. It determines how sound waves reflect at boundaries between different media.

4. Using the Calculator

Tips: Enter the density of the medium in kg/m³ and the speed of sound in that medium in m/s. Both values must be positive numbers.

5. Frequently Asked Questions (FAQ)

Q1: What are typical values of acoustic impedance?
A: Air: ~415 Pa·s/m, Water: ~1.5 MRayl (1.5×10⁶ Pa·s/m), Steel: ~47 MRayl. 1 Rayl = 1 Pa·s/m.

Q2: Why is acoustic impedance important in ultrasound?
A: The reflection coefficient at tissue boundaries depends on the impedance mismatch between tissues.

Q3: How does temperature affect acoustic impedance?
A: Temperature affects sound speed and density, thus changing impedance. For water, impedance decreases with increasing temperature.

Q4: What's the difference between specific and characteristic impedance?
A: Specific impedance is pressure/particle velocity at a point. Characteristic impedance is for plane waves in infinite media (what this calculator computes).

Q5: How is acoustic impedance measured experimentally?
A: Typically by measuring sound pressure and particle velocity, or through reflection coefficient measurements.