Physics: Difference between revisions - Bose Portable PA Knowledge

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== Spherical, Cylindrical, Plane-wave Sources ==

Most are familiar with the properties of one type of sound source – the spherical-wave source – because virtually every loudspeaker is an example of this type. But there are two other types: the cylindrical-wave source, and the plane-wave source. These sources are named for the shapes of the sound waves they produce, and each has significantly different properties:

- A spherical-wave source is shaped like a typical loudspeaker. Spherical sound waves expand in three dimensions – like an expanding sphere: out, left and right, and up and down.

:* A spherical-wave source is shaped like a typical loudspeaker. Spherical sound waves expand in three dimensions – like an expanding sphere: out, left and right, and up and down.

:* A cylindrical-wave source is shaped like a line. To produce cylindrical waves at musical frequencies the source must be high, about six feet (two meters), or higher. Cylindrical waves expand in two dimensions only – out and to the sides but not up or down (assuming the source is oriented vertically, like a flagpole).

~~Figure x. A spherical-wave source, shaped like a typical loudspeaker, sends sound energy in all directions (three dimensions)~~: ~~out, to the sides, and up and down.~~

:* A source capable of producing plane waves is itself planar, or sheet-like, in shape. To produce plane waves at musical frequencies the plane-wave source must be large, about six feet square (two meters square), or larger. Plane waves travel in only one direction, or dimension: out, but not to the sides or up and down.

- A cylindrical-wave source is shaped like a line. To produce cylindrical waves at musical frequencies the source must be high, about six feet (two meters), or higher. Cylindrical waves expand in two dimensions only – out and to the sides but not up or down (assuming the source is oriented vertically, like a flagpole).

Figure x. A spherical-wave source, shaped like a typical loudspeaker, sends sound energy in all directions (three dimensions): out, to the sides, and up and down.

Figure x. A cylindrical-wave source, shaped like a line, or pole, radiates sound in two dimensions: out and to the sides, but not up and down. The resulting radiation pattern is therefore wedge shaped.

- A source capable of producing plane waves is itself planar, or sheet-like, in shape. To produce plane waves at musical frequencies the plane-wave source must be large, about six feet square (two meters square), or larger. Plane waves travel in only one direction, or dimension: out, but not to the sides or up and down.

Figure x. A plane-wave source, shaped like a sheet, radiates sound in only one dimensions: out, but not to the sides, or up and down.

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 == Spherical, Cylindrical, Plane-wave Sources ==
 Most are familiar with the properties of one type of sound source – the spherical-wave source – because virtually every loudspeaker is an example of this type. But there are two other types: the cylindrical-wave source, and the plane-wave source. These sources are named for the shapes of the sound waves they produce, and each has significantly different properties:
--	A spherical-wave source is shaped like a typical loudspeaker. Spherical sound waves expand in three dimensions – like an expanding sphere: out, left and right, and up and down.
+:*	A spherical-wave source is shaped like a typical loudspeaker. Spherical sound waves expand in three dimensions – like an expanding sphere: out, left and right, and up and down.
+:*	A cylindrical-wave source is shaped like a line. To produce cylindrical waves at musical frequencies the source must be high, about six feet (two meters), or higher. Cylindrical waves expand in two dimensions only – out and to the sides but not up or down (assuming the source is oriented vertically, like a flagpole).
-Figure x. A spherical-wave source, shaped like a typical loudspeaker, sends sound energy in all directions (three dimensions): out, to the sides, and up and down.
+:*	A source capable of producing plane waves is itself planar, or sheet-like, in shape. To produce plane waves at musical frequencies the plane-wave source must be large, about six feet square (two meters square), or larger. Plane waves travel in only one direction, or dimension: out, but not to the sides or up and down.
--	A cylindrical-wave source is shaped like a line. To produce cylindrical waves at musical frequencies the source must be high, about six feet (two meters), or higher. Cylindrical waves expand in two dimensions only – out and to the sides but not up or down (assuming the source is oriented vertically, like a flagpole).
+Figure x. A spherical-wave source, shaped like a typical loudspeaker, sends sound energy in all directions (three dimensions): out, to the sides, and up and down.
 Figure x. A cylindrical-wave source, shaped like a line, or pole, radiates sound in two dimensions: out and to the sides, but not up and down. The resulting radiation pattern is therefore wedge shaped.
--	A source capable of producing plane waves is itself planar, or sheet-like, in shape. To produce plane waves at musical frequencies the plane-wave source must be large, about six feet square (two meters square), or larger. Plane waves travel in only one direction, or dimension: out, but not to the sides or up and down.
 Figure x. A plane-wave source, shaped like a sheet, radiates sound in only one dimensions: out, but not to the sides, or up and down.