NO. 138 DATA SHEET
No special precautions beyond ordinary care are necessary in the operation of the "Uniplex" microphones. They will operate efficiently and dependably under all ordinary conditions.
ACOUSTIC The high-frequency response of CONSIDERATIONS: the 730S is accentuated and the low frequencies are attenuated to give a smoothly rising response
characteristic. (See Fig. C). The result of this is a microphone in which a high degree of speech intelligibility is achieved without undue loss of quality. The expression "cardioid type" response simply means that the horizontal polar characteristic approximates a cardioid of revolution. There is a wide, useful pickup angle at the front of the microphone while the response at the sides is down 6 db and the rear response is down of the order of 15 db from the front side response over a broad range of frequencies. The true unidirectional characteristic of the "Uniplex" should not be confused with the relatively slight directional effect at high frequencies only which can be produced by baffle-effects in the conventional pressure microphone.
The result of this unidirectional characteristic is a complete elimination of acoustic feedback at volume levels which would cause considerable feedback with conventional semidirectional microphones. In practically all cases it is possible to increase loud-speaker levels when a Uniplex is installed. By direct-
ing the dead side (rear) of the microphone towards the audience or other source of interfering sound, pickup can be concentrated on the desired source. Reverberation energy pickup is decreased approximately two-thirds. The microphone can be placed close to reflecting surfaces without objectionable effects if the rear side of the microphone is toward the reflecting surface. This is particularly valuable in small halls.
It is desirable to experiment with microphone placement and orientation in order to secure the greatest benefits from the unidirectional characteristic.
SPECIFICATIONS
Voltage Sensitivity: 2.25 millivolts r.m.s. per bar at the end of a 7-foot cable across 1 to 5 megohms at 400 cycles.
This is equivalent to 53 db below 1 volt per bar.
Internal Output |
Equivalent to a 1500 micro-micro- |
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Impedance : |
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fared condenser. |
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Recommended Load |
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Impedance: |
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1 to 5 megohms. |
Height, |
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4-3/8 |
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Height, |
Case (h)* . |
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3-1/8 |
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Width (b)*. . . . . |
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3-1/8 |
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Thickness (c)*. . . |
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3-3/8 |
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Finish. |
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Satin |
Chrome |
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Net Weight. . . . . |
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2-1/4 |
lbs. |
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Shipping |
Weight . . |
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2-1/2 |
lbs. |
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Code Word . . . . . |
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RUPOD |
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* See Fig. B. |
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GUARANTEE: |
Each |
microphone |
is guaranteed |
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to be free from electrical |
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and |
mechanical |
defects for a |
period of one year from date of shipment from the factory, provided all instructions are complied with fully. In case of damage, return the microphone to the factory for repairs. Our guarantee is voided if the microphone case is opened.
LICENSE NOTICE: |
Shure patent 2,198,424. Other |
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patents allowed. |
Licensed |
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under patents of |
the Brush |
FIG. C TYPICAL FREQUENCY RESPONSE. SHURE MODEL 730S "UNIPLEX" MICROPHONE |
Development Company. |