Part 9
It's hard to believe that this is the 9th article in this series!  In future articles we'll attempt to focus on some other pieces of broadcasting equipment besides microphones...but this time I'd like to cover one more of the mainstays of the so-called “Golden Age” microphones...the Western Electric model 639 dual element mike. (1)

As the 1930s were drawing to a close...Bell Labs developed an excellent microphone design that was to come into direct competition with RCA's model 77 series that we covered previously.   Up to this point Western Electric, the manufacturing arm of Bell Telephone, had only built omnidirectional or non-directional mikes.   Bell Telephone laboratories needed to come up with a cardioid pattern (heart-shaped) or uni-directional microphone design that didn't impinge on RCA patents for the dual ribbon uni-directional design of the RCA 77.   In fact, up to this point, Western Electric hadn't made a ribbon microphone...but they did invent the dynamic mike design.  

The Bell Lab engineers came up with a mike that was two mikes in one! (2) They paired an “improved” bi-directional ribbon element with a non-directional dynamic unit similar to their very excellent “Eight-ball” mike.  They called this mike a “multi-mike” and dubbed it the model 639...it was given the nickname: “the birdcage” mike. (3) By combining the units two  outputs the result was the uni or cardioid pattern.     This, of course, was the exact same result as RCA obtained with their dual-ribbon design without going against RCA's patents.

The original idea from Bell Labs was to develop a microphone that would be useful in PA sound systems to prevent feedback under poor acoustical conditions.  One sound system that had bad acoustics was the US Congressional chamber.   Various mikes had been tried to no avail.   Western Electric did a test in the chamber with the 639 and the sound greatly improved.(4) The 639 mikes were used for decades in the Congressional Hall.   This mike became a favorite in the broadcast and motion picture industries as well.  

The original model 639-A had 3 basic patterns:   C-Cardioid (uni-directional, D-Dynamic (non-directional) and R-Ribbon (bi-directional).(5) Later the 639-B came out with three additional variations on the cardioid pattern giving varying degrees of front to back pickup.  (6,7)

When the United Nations building was first opened in New York Western Electric supplied all the microphones used in the General Assembly hall.  There were 3 model 639s on the main desk up front and many model 633 Saltshakers used at each nations delegation position in the hall.

As we mentioned in our earlier articles on Western Electric mikes....in 1949 manufacture of these units was transferred to Altec-Lansing Corp. (8) Altec continued to make the 633 Saltshaker and the 639 Multimike clear up into the late 60s.   These mikes were very popular during this period and were mainstays in the broadcasting and recording industries for decades.   Even today they are still sought after for their excellent quality even though they haven't been manufactured for some 40 years!

The 639 “Birdcage” was a favorite with announcers and disc jockeys...they loved the deep solid lows and the crisp high frequency pick up of their voices.  The 639 was used on overhead mike booms in the early days of TV as well as in film and recording studios for multi-track recording.   

So there you have it...a brief story of one of the great American made high quality microphones of the “Golden Age”...the Western Electric/Altec model 639 “Birdcage”.











A CBS-TV studio shot featuring a 639 Birdcage mike on the overhead boom.  The mike has a custom mounting using heavy rubber-band type suspension
Here's the late vocalist Frankie Laine in the studio belting out one of his many hits and using a model 639.

WDBO personality Dick Ravenhill with a model 639 hanging from a Starbird boom.

Here is a very young Gary Avey at the Armed Forces Radio Station at Subic Bay, Philippines in 1962.
An Altec 639A with Gates console and turntables also by Gates Radio Co.
A very young Gladys Knight singing into a dual 639 mike setup.
Here is the announce booth at Los Angeles “beautiful music” station KPOL in the 1950s.KPOL used Gates turntables and an Altec 639 mike.  (Marvin Collins)
KPOL air personality Chuck Bennett and his pal at the mike!  (Marvin Collins)

Marty Robbins at The Grand Old Opry.  WSM  used the Birdcage mikes for many years on the Opry stage
A radio news commentary-type show using four model 639s and the moderator using an RCA 77D.
WSB, Atlanta DJ who also played the Hammond Organ!  WE 639 mike hanging from an interesting looking boom!  (U of Maryland)
(2.)   Two very nice Altec examples with accessory yoke mounting...the green Altec quality control sticker is still on the mike at right!  (Stan Coutant microphone website)
(4.)   Company logo.
(5.)   Rear bottom of the 639B showing the 6 pattern selection switch. (Coutant)

(7.)   WE ad from the 1940s.
(8.)   Late 1960s Altec catalog page
(1.)   Western Electric debuts the new model 639A.

WJR Detroit air personality with his 639 and WE turntable.  (U of Maryland)
(3.)   Cutaway drawing showing the two mikes in one design. 


(6.)   WE ad from the 1940s.
A very busy DJ taking phone requests...the console is also made by Western Electric. (U of Maryland)