I bought this microphone out of curiosity! It caught my attention because I had never seen or heard of it before (shock, horror!). It came in its original felt lined wooden box, of the kind normally reserved for valuable scientific instruments. The name Gaumont I recalled from the old UK cinema chain but beyond that I knew nothing.
Researching this microphone has proved to be a challenging task.
It would appear that the Gaumont-Kalee Type 492 was never on sale to the general public. It was marketed along with other Gaumont-Kalee equipment purely within the cinema industry. So far the only contemporary references I have found have been in trade journals such as British Kinematography and Cine Technician.
It was manufactured by British Acoustic Films Ltd (B.A.F.), which by 1947, along with Gaumont-Kalee, was one of the many companies which made up The Rank Organisation.
Specifically designed as a boom mounted microphone, the Gaumont-Kalee Type 492 was most likely used to record dialogue and music for the classic British movies made at The Rank Organisation’s studios in the 1950’s. By this time The Rank Organisation in Britain had become one of the biggest film companies in the world. They owned 5 major studios including Pinewood and Ealing and Denham. Rank also owned and controlled distribution for several hundred UK cinemas.
B.A.F., under the Gaumont-Kalee brand, produced a number of sound recorders for the cinema industry, both optical and magnetic. Below is an advert from Cine Technician March-April 1953. My assumption based on this is that the Type 492 ribbon mic (and the Type 493 condenser not covered here) were designed for use with these machines. A 1947 BBC technical report on The G-K Sound on Film Recorder also makes passing mention of 2 microphones being supplied with the machine.
The Gaumont-Kalee Portable Recording Equipment pictured here features 35mm or 17.5mm sprocketed magnetic film which could be run in sync with a professional movie camera. In post-production this enabled easy editing and transfer.
These days when we talk about portable sound recording equipment we are maybe thinking of something the size of a mobile phone. The ‘portable’ equipment described above would have filled the boot of a car and required fairly muscular crew to carry it! However, its mobility nevertheless extended the possibilities of location recording both for TV and film production. (Also worth mentioning that magnetic film made a considerable improvement to the available frequency response.)
From this advert it can be noted that other users included BBC Television, Universal, a number of Newsreel companies, San Angel Inn (Mexico) and Dear Film (Rome).
Technical Information on the Gaumont-Kalee Type 492
In the absence of any detailed manufacturer’s literature, below I have made some observations and speculation about the design of this mic.
Noise has always been the enemy of the motion picture sound recordist, whether it be camera and equipment noise, on-set noise, tape hiss, or electrical interference generated by lighting. Trying to obtain clarity, especially in dialogue, has always been something of a challenge. This was particularly true in the age before shotgun mics.
- In common with all figure of eight microphones the dead zones at the sides of the Type 492 could be directed to minimise unwanted mechanical noise from cameras and other equipment.
- The yellow wiring around the ribbon is cunningly arranged to form a humbucking loop, helping to reject electromagnetically induced–noise. This is very useful when operating in the vicinity of lighting equipment and large mains transformers radiating strong magnetic fields.
- In addition, the interior of the grill is lined with ultra-fine wire mesh which not only provides a certain amount of blast protection and back pressure for the ribbon but also creates an effective Faraday Cage.
- The interesting-looking baffle arrangement on either side of the ribbon has the effect of producing a boost to the high end frequency response. This may provide greater clarity to dialogue, especially when recording at a distance (in order to keep the boom mounted 492 out of the camera shot). It was also common practice at this time to boost signals going to magnetic tape at around 4kHz on the way in and cut by the same amount on playback. This returned the desired signal to flat and reduced unwanted tape hiss by several db.
- The connector pictured above is a Reslo. This mic came with a 3 pin Amphenol. When I took the mic apart it became clear that this was a modification as it was chipped and had been filed to fit! Stewart Tavener at Xaudia informed me that the two 492s he had previously repaired had Reslo connectors. The Reslo fitted perfectly. Thanks Stewart!
- Unlike many of the ribbon microphones of the period which have impedances of 50 ohms or less, this Gaumont-Kalee Type 492 has an impedance of 300 ohms with a strong output signal which requires considerably less amplification than many of its contemporaries.
So what does the Gaumont-Kalee Type 492 sound like? CLICK HERE.
Having emailed academic institutions, museums, collectors and fellow sound engineers all over the world, so far I have only tracked down a handful people who have come across the Type 492. The serial number on mine is 132 and I assume from the complete dearth of information that only a limited number were made. Sadly, much of the recording equipment from that period has long since gone in the bin along with company records, technical literature and drawings. Trying to unearth information about the Gaumont-Kalee Type 492 has highlighted to me the growing problem of vanishing history in the field of audio technology. Living links to the past are dying out and records are being lost. It is therefore important to preserve what we can before it is too late!
NEWS FLASH UPDATE 12 Nov.2019
have kindly unearthed this single page ad for the Gaumont- Kalee Type 492 and Type 493 in a May 1951 GB-Kalee product catalogue ‘Everything for the Cinema and Theatre’. GB Kalee Type 492 Advert 1951
UPDATE 28th Nov.
Stroke of luck! Have just purchased this GB-Kalee Catalogue for 1950 on ebay and here on page 4 are the frequency response graphs for the Type 492 and 493!
Gaumont British-Kalee proudly projects it’s brand across the world! The British Empire is marked in pink. Within a couple of decades the Empire was gone along with GB-Kalee and most of British industry! (N.B. Even by 1950 the map above was out of date. India got rid of us in 1947 !)
https://www.gettyimages.co.uk/detail/news-photo/an-engineer-works-on-a-laboratory-set-up-to-develop-news-photo/90777079?adppopup=true Taken at B.A.F. factory at Mitcheldean in Gloucestershire in 1953, on the workbench is a Gaumont-Kalee Type 492. The zeppelin shaped mic up in the air is the Type 493 condenser.
http://xaudiaelektrik.blogspot.com/2014/02/motm-gaumont-kalee-type-1492-ribbon-mic.html It is interesting to note that the microphone featured here has a 1 inserted in front of the 492. Apart from having an impedance of 50 ohms, what the difference was I have no idea.
BBC L2 (STC4104 A) Lip Ribbon Microphone Circa 1955
When this BBC L2 (STC4104 A) first arrived, I thought that I might lavish some TLC on it’s battle-scarred wooden case to make it look a bit smarter. However, the more I look at it, the more I think that I shall leave it just as it is. This microphone has clearly been around the block a few times and has history. The two stickers on the lid are REPAIR and TESTED labels from the BBC Equipment Department in the mid 1980’s. By then it had already been in service for 30 years!
I always feel a bit sad when I see a vintage microphone advertised on a selling site as being “Unopened in original box”, or simply “NOS”. No history, just old. Certainly not the case for this BBC L2 (STC4104 A). Opening the lid of the box reveals a microphone which has had a lot of use!
Most high quality microphones spend their lives cosseted, and looked after by skilled engineers, in the well regulated environment of a recording or broadcasting studio. This BBC L2 lip ribbon microphone has spent its life on the road with journalists, commentators and broadcasting crew. What is really amazing is that it is still in great working condition, along with its original 3 position Equaliser.
The only down side to this piece of kit is that the microphone, equaliser, and case have a combined weight of 13lbs! Most of this is the equaliser. Later models dispensed with the EQ. Instead the MED BASS roll-off was built into the microphone. However, it is pretty clear from the big splodge of red paint, that even with this mic, MED BASS was the preferred setting.
The BBC designed the L2 in 1951 as an updated version of the L1 which had been in service since 1937. It arrived just in time to play a starring role in the televised Coronation of Elizabeth II, when it was used to capture the famous commentary by Richard Dimbleby in Westminster Abbey. Dimbleby was known as the “Voice of the Nation”, and so on this occasion the L2 was perhaps the “Ear of the Nation”, into which he delivered his stately measured tones. It was the first mass-televised event in Britain. Shops selling televisions ran out of stock as people bought them for the first time!
(Watch from 3.30m)
The BBC L2 (STC4104 A) also made it possible to clearly broadcast commentary from even the noisiest of environments.
This microphone has an extraordinary ability to cancel out and reject unwanted surrounding sounds. It is particularly insensitive at the sides of the mic in the dead zones of the ribbon.
Here is Kenneth Wolstenholme at the 1966 Football World Cup.
CLICK LINK below to hear the end of the match !
CLICK HERE to hear my STC4104 A in action!
CLICK HERE to hear the STC4104 A delivering a VOCAL. (Great new look for any singer!)
In previous posts I have occasionally (often) moaned about the difficulty of finding information about various vintage microphones. In the case of the L2 lip ribbon microphone, because it was designed by the BBC, there is a wealth of documentation available. Rather than writing a lengthy technical description myself, I would recommend reading the BBC Monograph which appears below. This explains the design and usage of this classic microphone in great detail.
P.S. Today a version of the BBC L2 (STC4104) lip ribbon microphone is still made by Coles and is widely used by journalists and commentators all over the world.
Posted in 1930s Microphone, 1940s Microphone, 1950's Microphone, 1960's Microphone, BBC Microphones, Commentators Microphone, Microphone Tech Specs, Microphone techniques Ancient & Modern, Noise- cancelling microphones, Ribbon Microphones, STC Microphones, STC4104 A, Uncategorized, Vintage Broadcasting, Vintage Brochures and Tech Specs, Vintage Microphones
Tagged 1950's Microphone, BBC Microphones, Microphones for Television, STC Microphone, Vintage Microphone