Acoustic transfer function of an isothermal line
Thermoacoustic converters - Thermoacoustic effect

The value of introducing the matrices or thermoacoustic transfer functions of a circuit's components is obvious when modeling for optimization. The theory developed above also makes it possible to characterize an isothermal component by its characteristic matrix M_di. Thus, for the case of isothermal walls, let B_T ≥ 0, neglecting thermal relaxation 1/r_T, and positing for acoustic admittance A_U ≥ jωc_u, with Δ ≥ – 4C_T ≥ 4Z_UA_U , we finally find the following matrix: