Microphone Man-20

Part 20

RCA Starmaker

RCA BK 4 Starmaker
BK-11A bi-directional microphone

Another of the Microphone-Man favorites was the RCA “Starmaker” omnidirectional ribbon microphone. Yes, I said Omnidirectional. Most people think of ribbon mikes as bi-directional as in the RCA 44 and the RCA Jr. Velocity 74B. But, believe it or not, RCA produced a slender, omni-ribbon model in the early 50s…the model BK4.  RCA named it the “Starmaker” and I have a strong suspicion that RCA was trying to one-up Altec Lansing with their coke-bottle condenser mike.  The “Starmaker” had a shape that was just too close to the Altec to be otherwise. Of course there were the Electro-Voice “Slim-Trim” dynamics that were making inroads into RCA’s microphone business, too.

So how did they make a ribbon mike be omnidirectional and how did they get it into such a small package? Remember that RCA’s model 77 series of uni-directional mikes had multi-directional models in which one of the pickup patterns was omnidirectional. This was done by enclosing the one side of the ribbon in a pipe that lead to a damped acoustic chamber filled with sound absorbing material. This allowed sound to enter the mike from the front side of the ribbon element only. Thus you had what’s called a “pressure” microphone which is naturally non-directional.

RCA put the ribbon element at the top of a long 7 inch barrel that was one and a quarter inches in diameter. The back side of the ribbon was facing directly into a folded acoustically damped pipe designed to form an acoustic resistance for the moving system. The front of the ribbon
was brought to the sound pickup point through a smaller 5 inch long tubular section terminating in a short horn. There was a screen at the sound entrance point which was 7/8″ in diameter.

The magnet structure of the “Starmaker” was pretty small so the output level was somewhat lower than most of RCA’s other mikes. RCA stressed that the “Starmaker” was self-contained and did not require any special power supply or cables which was a direct dig at Altec! The “Starmaker” was finished in TV gray and had a frequency range of 70 to 15,000 hertz. I could be used as a hand-held mike or could be mounted on a mike stand. There was a transformer below that acoustic chamber to give a selection of output impedance of 30, 150 or 250 ohms.

In spite of it’s advantages and rather nice appearance…the “Starmaker” was not produced for very long and apparently did not become very popular. I’m sure the folks at Altec had a chuckle or two over that! Their similarly shaped Altec “coke-bottle” mike was very popular and Altec sold thousands of them from 1949 clear into the 60s.

The production of the RCA “Starmaker” ceased around 1955 after being produced for only two or three years. It was designed particularly for the TV market and NBC used them on the “Today” show when Dave Garroway was the host. Dave would walk around the studio with a “Starmaker” attached to a neck harness…this was in the days before lavalier-type mikes…it could not have been very comfortable!


Gary tests the RCA 77D


  ↑One more  test of  the RCA  77D

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