# Intuition of sound wave impedance and admitance

The impedance of a soundwave is given by both: $$\frac{\mathcal{P}}{V}=\rho_0c$$ Where $$\mathcal{P}$$ is the pressure wave, $$V$$ is the velocity vector of particles, $$\rho_0$$ is the static value of the gas density and $$c$$ is the speed of sound\wave. It is very easy for me to understand an impedance in an electrical circuit. The impedance of a capacitor is a measure of how will a capacitor influence the current (flow of electrons through a conductor). In particular, impedance is the negative influence on the current while admittance is a positive influence.

Is there an intuitive explanation with respect to a sound wave? Looking at the $$\rho_0c$$ term it seems to me that this is a medium-wise constant value. Is that correct? Is there another\better intuition?

• The electrical analogy is that pressure is like voltage (or E-field in an electromagnetic wave) and velocity is like current (or H-field).
– Puk
Jun 15, 2020 at 19:14

Impedances in circuits are extrinsic while in your questions you are showing the intrinsic acoustic impedance. As you pointed out, it is a material property and intuitively you can say that it shows you how easy it is for a given pressure to obtain a particular particle velocity. I suggest that you check my previous answer on the topic.

• Very helpful. "shows you how easy it is for a given pressure to obtain a particular particle velocity" was what I was missing from your previous answer. Thanks a lot!. Jun 16, 2020 at 15:30