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The RCA Type BK-6B
miniature dynamic microphone

RCA Type BK-6B

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Description
The BK-6B dynamic pressure microphone is a high-quality instrument of the pressure-actuated type. It is especially designed for correct speech balance when used informally in television broadcasting and public address applications.

The human voice has pronounced directional characteristics. The high-pitched nasal and sibilant sounds which give crispness and definition to speech are emitted in a comparatively narrow angle from the front of the face. The low-pitched sounds from the throat and chest are emitted approximately equally in all directions.

In normal studio or announce use, the microphone is placed so that the performer speaks directly into it. In television, the microphone is frequently placed on one side, either mounted on a boom, held in the hand, or concealed on the set. Each of these positions may result in a loss of the high-frequency sounds which are important in pleasing and natural speech reproduction.

BK-6B frequency response

The frequency response (Figure 3) and directional characteristics (Figure 4) of the BK-6B are designed to complement the characteristics of human speech. The result is a microphone which has excellent balance when the performer is talking “off mic.”

BK-6B polar response

The BK-6B is especially designed to be suspended from the neck, resting on the chest. The low-pitched chest sounds are attenuated. The microphone points straight up toward the lips, the position in which it is most sensitive to the sibilant sounds that would normally be lost. If it is desired to talk directly at the microphone, it may be held either so that the speaker talks across it or into it, depending upon the response desired for the particular speaker’s voice.

The general rule is to talk across the BK-6B, either in an interview, a panel discussion, or with the microphone suspended around the neck. In this manner, a balance similar to the RCA 77-DX in its Unidirectional V1 position is obtained.

The BK-6B is designed as a speech microphone; it is not recommended for music pickup.

The BK-6B is especially recommended for television broadcasting. It may be worn by the performer; its small bulk and neutral color make it inconspicuous. The light weight, flexible cable permits free, unhampered movement of the performer. It may be wholly concealed in a man’s hand during an interview. It is easily concealed on a set. The styling blends easily with any props, and is pleasing where it is exposed to direct view.

The RCA BK-6B

The RCA BK-6B

Technical Data

  • Effective Output Level at 1000 cycles: –67 dBm; Sound Pressure 10 dynes/cm²

  • Frequency Response: 80 to 12,000 cps (see Figure 3)

  • Mounting: Lanyard (supplied)

  • Output Impedance: 30, 50, or 250 ohms (Connected for 250 ohms when shipped)

  • Hum Pickup: –112 dBm, hum field 10–3 gauss

  • Dimensions and Weight
    Length: 2916 inches
    Diameter: 1516 inch
    Weight: 213 ounces, less cable

  • Finish: TV Gray

  • Cable: 30 feet, special flexible two-conductor shielded

  • Directional Characteristics: See Figure 4

  • Accessories
    MI-12086 Stand Holder
    MI-11073 Stand Adapter Kit
    MI-11745 Flexible Microphone Stand (13")
    MI-11746 Flexible Microphone Stand (19")

BK-6B schematic diagram

BK-6B cross-section

Quoted from RCA Instructions, BK-6B Miniature Dynamic Microphone, MI-11017-A

RCA Type BK-6B

1967 RCA catalog page

1967 RCA catalog page

RCA Type BK-6B instructions
Download the Instructions for this mic.
Seven pages, 656KB pdf
 

 

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