. 2019 Oct 16;19(20):4487. doi: 10.3390/s19204487

Table A1.

Lumped parameter model for the acoustic impedance Z_bpc of the system for static pressure equalization (SPEQ) [kg/s/m⁴], [23].

$R_{b p c} = \frac{8 l μ}{π r^{4}}$	R_bpc: acoustic resistance of the vent channel [kg/s/m⁴]	(A1)
$I_{b p c} = \frac{4}{3} \frac{ρ l}{π r^{2}}$	I_bpc: acoustic inertance of the vent channel [kg/m⁴]	(A2)
$C_{b p c} = \frac{V_{i c}}{ρ c^{2}} V_{i c} = l_{i c} b_{i c} h_{i c}$	C_bpc: acoustic compliance of the cavity *V_ic* [m⁴s²/kg].	(A3)
$Z_{b p c} = R_{b p c} + i ω I_{b p c} + \frac{1}{i ω C_{b p c}}$

l = 0.4 mm: length of the vent channel (orifice); r = 0.07 mm: radius of the orifice; length l_ic = 3 mm, width b_ic = 1.5 mm and height hic = 0.5 mm of the cavity; V_ic, c: speed of sound in air [m/s]; μ: dynamic viscosity of air [Pa s]; and ρ: density of air [kg/m³].