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RCA Type 77-A Microphone
The RCA Type 77-A microphone was a simplex (''uni-directional'') ribbon microphone, the forerunner of the RCA Type 77-DX microphone The RCA Type 77-DX microphone is a poly-directional ribbon microphone, or pressure-gradient microphone, introduced by the RCA Corporation in 1954. It was preceded by the Type 77-D introduced in 1948. Its popularity and classic design has resulted .... The 77-A was designed Dr. Harry F. Olson in the late 1920s or early 1930s; prototypes are rumored to have existed in 1929 and 1930, but the 77-A was not announced until 1932. The 77-A would set the standard for all other RCA ribbon microphone comparisons for the next 40 years. Construction It featured a spiral acoustic labyrinth inside the case and two vertical in-line ribbons which enabled it to be uni-directional. External linksRCA Type 77-A information from www.coutant.org {{product-stub Ribbon microphones ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Simplex
In geometry, a simplex (plural: simplexes or simplices) is a generalization of the notion of a triangle or tetrahedron to arbitrary dimensions. The simplex is so-named because it represents the simplest possible polytope in any given dimension. For example, * a 0-dimensional simplex is a point, * a 1-dimensional simplex is a line segment, * a 2-dimensional simplex is a triangle, * a 3-dimensional simplex is a tetrahedron, and * a 4-dimensional simplex is a 5-cell. Specifically, a ''k''-simplex is a ''k''-dimensional polytope which is the convex hull of its ''k'' + 1 vertices. More formally, suppose the ''k'' + 1 points u_0, \dots, u_k \in \mathbb^ are affinely independent, which means u_1 - u_0,\dots, u_k-u_0 are linearly independent. Then, the simplex determined by them is the set of points : C = \left\ This representation in terms of weighted vertices is known as the barycentric coordinate system. A regular simplex is a simplex that is also a regular polytope. A ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ribbon Microphone
A ribbon microphone, also known as a ribbon velocity microphone, is a type of microphone that uses a thin aluminum, duraluminum or nanofilm of electrically conductive ribbon placed between the poles of a magnet to produce a voltage by electromagnetic induction. Ribbon microphones are typically bidirectional, meaning that they pick up sounds equally well from either side of the microphone. Principle of operation In a moving-coil microphone, the diaphragm is attached to a light movable coil that generates a voltage as it moves back and forth between the poles of a permanent magnet. In ribbon microphones, a light metal ribbon (usually corrugated) is suspended between the poles of a magnet. As the ribbon vibrates, a voltage is induced at right angles to both the ribbon velocity and magnetic field direction and is picked off by contacts at the ends of the ribbon. Ribbon microphones are also called "velocity microphones" because the induced voltage is proportional to the velo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
RCA Type 77-DX Microphone
The RCA Type 77-DX microphone is a poly-directional ribbon microphone, or pressure-gradient microphone, introduced by the RCA Corporation in 1954. It was preceded by the Type 77-D introduced in 1948. Its popularity and classic design has resulted in the 77-DX becoming an iconic microphone, used by broadcasters and media personalities such as Edward R. Murrow, David Letterman and Larry King. Controls The directionality of the 77-DX is variable. A rotating backshutter on the acoustic labyrinth, controlled by a screwdriver-operated slot at the rear of the microphone, allows the user to vary the microphone's pattern from omnidirectional in the fully closed position, to cardioid, to figure-8 (bidirectional) in the fully open position. A 3-position switch at the bottom end of the microphone allows the user to control the amount of low-frequency rolloff. Response and output characteristics At 1 kHz, the 77-DX has an output of -50 to -56dbm, depending on the pattern selection. The o ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Harry F
Harry may refer to: TV shows * ''Harry'' (American TV series), a 1987 American comedy series starring Alan Arkin * ''Harry'' (British TV series), a 1993 BBC drama that ran for two seasons * ''Harry'' (talk show), a 2016 American daytime talk show hosted by Harry Connick Jr. People and fictional characters * Harry (given name), a list of people and fictional characters with the given name * Harry (surname), a list of people with the surname * Dirty Harry (musician) (born 1982), British rock singer who has also used the stage name Harry * Harry Potter (character), the main protagonist in a Harry Potter fictional series by J. K. Rowling Other uses * Harry (derogatory term), derogatory term used in Norway * ''Harry'' (album), a 1969 album by Harry Nilsson *The tunnel used in the Stalag Luft III escape ("The Great Escape") of World War II * ''Harry'' (newspaper), an underground newspaper in Baltimore, Maryland See also *Harrying (laying waste), may refer to the following historical ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
