## 6.6. Sound pressure produced at distance r

We show in

Eq. (13.104) that the far-field on-axis pressure produced by a plane circular piston in an infinite baffle is given by

$\begin{array}{c}\tilde{p}\left(r\right)=jf{\rho}_{0}{\tilde{U}}_{c}\frac{{e}^{-jkr}}{r}\\ ={\rho}_{0}{S}_{D}{\tilde{a}}_{c}\frac{{e}^{-jkr}}{2\pi r}\end{array}$

(6.31)
where

${\tilde{a}}_{c}$
is given by Eqs. (

6.8), (

6.9), and (

6.13) so that

$\tilde{p}\left(r\right)=\frac{{\tilde{e}}_{g}Bl{S}_{D}{\rho}_{0}}{\left({R}_{g}+{R}_{E}\right){M}_{MS}}\xb7\frac{{e}^{-jkr}}{2\pi r}{\alpha}_{c}$

The frequency response ...