$c$	speed of acoustic wave in the medium (m/s)
$I$	acoustic intensity
$K$	bulk modulus
$p_{rms}$	root mean square of sound pressure
N	number of data points
$p_i$	instantaneous pressure/incident pressure (Pa)
$p_r$	reflected pressure (Pa)
$p_t$	transmitted pressure (Pa)
$\overline{P}$	average value of $p_i$
$P_0$	amplitude of the waves originating from the source (Pa)
SPL	sound pressure level (dB)
$x$	distance from the distributor along the bed height (m)
$\overline{x}$	dimensionless distance from the distributor, i.e., $\overline{x}=x/L$ (m/m)
z	specific acoustic impedance
L	height of the acoustics source from distributor (m)
Greek symbols
μ	air viscosity at room temperature (N·s m–2)
k	wave number
f	acoustic frequency
ω	angular frequency
λ	wavelength
α	acoustic power transmission coefficient
ρb	bulk density of the medium (kg/m3)
ε	bed porosity