A programa calculates speed of sound for a temperature range of 0 to 30 degrees C and relative humidity 0 to 100% RH.

The algorithm is based on the approximate formula published in JASA [1993] by Owen Cramer, "The variation of the specific heat ratio and the speed of sound in air with temperature, pressure, humidity, and CO_{2} concentration."

f (t, p, x_{w}, x_{c}) = a_{0}
+ a_{1 }t + a_{2 }t^{2}
+ (a_{3 }+ a_{4 }t + a_{5
}t^{2}) x_{w} + (a_{6}+ a_{7 }t + a_{8 }t^{2)}p + (a_{9 }+a_{10 }t +a_{11
}t^{2}) x_{c} + a_{12 }x_{w}^{2}
+ a_{13 }p^{2 }+ a_{14 }x_{c}^{2
}+ a_{15 }x_{w }p x_{c} where the t is the celsius temperature, p is the pressure, x_{w} is the water vapor mole fraction, and x_{c} is the carbon dioxide mole fraction.
The coefficients are:
a_{0} = 331.5024
a_{1} = 0.603 055
a_{2} = -0.000 528
a_{3} = 51.471 935
a_{4} = 0.149 587 4
a_{5} = -0.000 782
a_{6} = -1.82 * 10^{-7} a_{7} = 3.73 * 10^{-8} a_{8} = -2.93 * 10^{-10} a_{9} = -85.209 31
a_{10} = -0.228 525
a_{11} = 5.91 * 10^{-5} a_{12} = -2.835 149
a_{13} = -2.15 * 10^{-13} a_{14} = 29.179 762
a_{15} = 0.000 486

x_{w }= h f p_{sv} / p where h is the relative humidity expressed as a fraction, f is the enhancement factor, and p_{sv} is the saturation vapor pressure of water vapor in air.

f = 1.000 62 + 3.14 * 10^{-8} p + 5.6 * 10^{-7
}t^{2}