Heath Consultants Aqua-Scop - Manual (Page 19)

The Velocity of Sound is given by:
Where: V = Velocity
γ = the ratio of the specific heat at constant pressure to
the specific heat at constant volume.
R = the universal gas constant.
T = Absolute Temperature (degrees Kelvin).
m = Gram Molecular Weight of the gas.
Therefore, the Velocity of Sound in Air is:
Velocity = 331
(At 68° F the velocity = 1125 ft./sec.).
The resonant frequency of rods, plates, pipes, strings, etc. is a function of
the shape, density, elastic properties, and boundary conditions defining
the object(s). In the case of a string, the fundamental resonant frequency
is proportional to the Transverse Velocity and inversely proportional to
length.
Sound dissipation along a fixed length of rod or pipe will be effected by
transit time, constraining forces along the wall perimeter, and the media
in the pipe. Discontinuities may drastically reduce sound transmission.
Point source sound propagating in a spherical pattern dissipates (with no
consideration of losses due to absorption reflection or interference) in sound
pressure per unit area as the square of distance. This means a pressure
decrease of 12 decibels each time the distance traveled doubles.
Sound waves, like other forms of energy, experience reflection and
refraction at the boundary between two media. Interference can occur when
two waves from the same source travel different path lengths and reunite.
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