RCA Type SK-46
Program Velocity microphone

Application
The RCA Type SK-46 Program Velocity Microphone is useful for AM, FM, and TV or studio control room announcing. Its excellent response, directional characteristics and small size make it a valuable and versatile instrument where quality production of sound is desired. The directional characteristics reduce unwanted acoustical background noise, reflections and feedback. This makes the microphone appropriate for “on stage,” announce booth and general indoor programs. The microphone is not recommended for outdoor use because of the relative sensitivity of this type unit to wind.

Description
The SK-46 is a small light weight velocity microphone in which the moving element is a thin, corrugated metallic ribbon supported at the ends and placed between the poles of two powerful magnets in a magnetic circuit. Because of its light weight, the motion of the ribbon corresponds very closely to the velocity of air particles; therefore, the voltage generated by it is a faithful reproduction of the sound waves that traverse it. The ribbon is connected to the primary winding of a small efficient transformer whose secondary winding matches either 150–250 ohms or high impedance, as required. The change in impedance is easily accomplished by changing one soldered connection inside the microphone. A swivel arrangement permits tilting the microphone back approximately 85°. Pleasing functional design incorporating excellent performance and rugged construction, attractively finished in TV gray and satin chrome, makes this microphone a welcome addition to any installation. A two-conductor shielded cable permanently attached to the microphone is connected for low impedance operation as stocked.

Features

• Bi-directional characteristics over wide frequency range
  
  
• Light weight, small in size
  
  
• Modern styling blends pleasingly with any background
  
  
• Adjustable impedance taps
  
  
• TV Gray and satin chrome finish
  
  
• Swivel mounting
  
  
• Extremely rugged construction
  

Quoted from RCA Catalog B sheet 1022, dated March, 1955

Directional characteristics of the SK-46 Velocity Microphone

From a recent eBay auction

Download the Catalog B sheet.
Eight megabytes, high-resolution pdf