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Microphones have been around since Alexander Graham Bell invented the telephone. In radio, television and recording, the microphone is the the very first instrument used in the process of picking up sound. So the “mike” is
pretty important and went through development from relatively primitive devices in the early days to units that could very faithfully reproduce the full range of humanly audible sound.
In this segment I want to concentrate on those broadcast-type microphones that had a huge impact on the industry from the early 1930s through the 1960s.
Here is one of the most recognizable broadcast and recording microphones made in the USA. The RCA model 44 series. These were first developed back in the 1930s by Harry Olson of RCA Labs in Camden New Jersey.
The first in this series was the 44A. The model 44 microphones were called “ribbon-velocity” microphones because the internal workings were comprised of a thin corrugated aluminum element, called a “ribbon” suspended in a strong permanent magnet field. This ribbon was the generating element taking sound waves and generating a tiny electrical current that was an exact representation of the sound. This small signal was stepped up by a transformer so it could be sent down the cable to the equipment it was connected to.
The basic ribbon-velocity microphone has a bi-directional pickup pattern. That means that it picks up sound equally well from the front and back of the mike but is relatively dead to sound arriving from either side. This pick up pattern was very useful in the so called “golden age” of radio…especially in dramatic programs where several actors could be grouped around the mike. There could be two or three actors facing the front side and another group facing the back side of the ribbon mike and all would be picked up equally well.
If the script called for someone to walk into a scene the actor would move from one of the dead sides of the mike to a live side providing a perfect “fade-in” The same could be done in reverse for a “fade-out”.
Radio announcers always loved ribbon mikes because they tended to make the voice sound more “bassy” or deep sounding when worked closeup. One of the problems with this is that the ribbon element was very fragile and could be easily stretched by a blast of breath from a close-talking announcer. This also caused a big “pop” in the audio. RCA recommended aworking distance of a foot or more for ribbon mikes….of course this was predicated on having a well designed studio with proper acoustics!
The RCA 44s were used by all the major radio and TV networks, local radio and TV stations, as well as recording studios. They were excellent for music pickup as well as voice. The 44 is a heavy weight in more ways than one….it weighed in at 8 pounds!! Obviously the 44 was not intended as a hand mike! Also it could not be used outdoors where wind was a factor and the big warning for any user of a ribbon mike was….”don’t ever blow into it”!
These mikes are still in demand and have seen a resurgence in recent years with digital recording. Although RCA stopped making microphones about 1973, there are ribbon mikes being manufactured new today by many makers here in the US as well as China and Russia. The ribbon mike has a very smooth, mellow sound that is very pleasing to the ear.
You can find old RCA 44 ribbon mikes selling on Ebay for up to several thousand dollars. This is a testament to the enduring quality of these units even after over 50 years since they stopped being manufactured. The amazing thing is you could have bought a brand new 44BX in 1957 for $129…of course, that’s in 1957 dollars!
There is a company in Pasadena, Audio Engineering Associates, that makes an exact replica of the RCA 44 called the AEA 44…..They sell for around $4,000. Some of the biggest recording studios are using these modern replicas in music productions of all kinds today.
So that’s the brief story of the RCA model 44. For more info on this and many other microphones, I recommend Stan Coutant’s website www.coutant.org. Stan has pictures and specs and also audio sound bites to give you an idea of how various mikes sound.
In future posts I’ll review other great broadcast mikes like the RCA 77 and the Western Electric/Altec 639 “birdcage” and several more.
Our previous sessions have dealt with ribbon microphones by RCA, one of the two prime makers of broadcast and sound equipment in the mid 20th century. This time we’ll turn to the other of these major makers, Western Electric Company.
RCA and Western Electric were fierce competitors in this era. I think I am safe in saying that the majority of radio stations from the 1920s through around 1950 used either RCA or Western Electric equipment, or a combination of both. Western Electric was the manufacturing arm of Bell Telephone…but also made broadcast equipment designed by Bell Telephone Labs. In 1949 Federal anti-trust laws forced Western Electric to divest of their broadcasting equipment manufacturing. Both these companies made just about everything needed to equip a station from microphones and audio control to transmitters and antennas.
About the time RCA came out with the revolutionary ribbon microphone…Western Electric developed the first high-quality dynamic microphone. The dynamic uses the same basic principle as the ribbon….a moving conductor in a magnetic field to generate the audio signal from sound waves. Instead of a moving foil ribbon…the dynamic uses a round-shaped diaphragm that has a coil of wire attached that moves in the magnetic field…it’s a small electric generator. Another way of explaining a dynamic microphone is to think of it as a loudspeaker in reverse! A loudspeaker takes a signal from a radio receiver or amplifier and turns that electric signal into sound we can hear. A microphone, as we explained before, takes that sound we hear and translates it into an electrical signal so it can be amplified and sent to a loudspeaker, as in a PA system, or for broadcasting or recording.
Western Electrics’ new dynamic microphone was dubbed the model 618 and came out about 1931. The model 618 was an omni-directional…or non-directional mike that was relatively small in size and very rugged…making it excellent for studio as well as remote broadcasting, especially in the outdoors. This mike was not sensitive to wind and breath noises like the ribbon mike…and it was relatively insensitive to handling noises making it excellent as a hand mike for interviews and such.
The model 618 was a great improvement over the earlier noisy carbon and bulky condenser mikes of that era. The 618 was a big hit with the radio industry and these mikes were used clear into the 50s. RCA, of course, would not be left behind by Western Electric….so they shortly came out with a very similar-looking mike they called the model 50A. Internally the RCA model 50A used a slightly different way of embedding the wire into the diaphragm so as not to infringe on Western Electrics’ patents….but externally they looked very similar.
You’ll see both of these mikes in news photos and newsreels of the day…they were used for President FDR’s “Fireside Chat” broadcasts. If you look closely at these photos you’ll see that CBS and Mutual (MBS) used the Western Electric and NBC and the Blue networks used the RCA because NBC was owned by RCA.
A few smaller manufacturers also made mikes that looked very much like the Western Electric and RCA units but these smaller outfits could not compete with the two giants in the broadcast industry and their mikes were used mainly in PA systems and some smaller radio stations.
The dynamic-type microphone is one of the most used units up to this very day…and Western Electric was the start of it all. These pioneering mikes were all omni-directional….picking up sounds from all around…later a small company, at the time, named Shure Brothers designed the first uni-directional dynamic mike called the “Unidyne”. Most dynamic mikes today are uni-directional picking up sound from the front side of the microphone and rejecting sounds from the rear, thus preventing sound system feedback (howling) and eliminating background noises, and all based on Shure’s ground-breaking development of the late 1930s.
We’ll save that story for another session.
Spec sheet for the WE 618 4