Martin Audio Wavefront W8CT, Application Manual

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5.3 Classic line array behavior
Although the vertical coverage of a single point source may be wide, when arrayed in
a straight line, multiple sources vector sum to form a tight vertical coverage pattern
that narrows with increasing cluster height and frequency following the classic law
for multiple source line arrays.
* = speed of sound (m/s).Varies with temp.
Arcsin = "the angle whose sin is…"
Nd = the total height of the column in meters
Propagation
Under normal conditions a wavefront moves through air at about 340m per second.
Air gets its properties from the weight and speed of its molecules. Molecules of
different weight (other gases maybe) or different velocity (that translates into
temperature) will exhibit different speeds of sound. Motion of the sound source, the
listener, or the air itself has no effect on the speed of sound, nor does the pressure of
the air.
An impulse applies energy to the air. (This energy becomes a difference in pressure in
front of and behind the wavefront.) As the front expands, the energy is spread over a
larger and larger area, in a way suggested by the relationship between the radius and
area of a sphere. The total energy stays the same, the area expands, so the energy in
one unit of area decreases with the square of the distance from the source.
All material © 2007. Martin Audio Ltd. Subject to change without notice.