Category Archives: 1950’s Microphone

The Ronette ‘CORONATION 53’ Crystal Microphone

What is a Crystal Microphone.

When pressure is applied to a crystal of Rochelle salt (sodium potassium tartrate tetrahydrate), causing it to flex, a tiny electrical charge is induced on its surfaces which is proportionate to the amount of pressure applied. Below is a simple diagram illustrating how this piezoelectric property is utilised in a crystal microphone.      

As sound waves cause movement of the diaphragm, varying pressure is applied to the crystal. The electrical signal thereby created can then be amplified to produce audio.

Rochelle salt is fragile and susceptible to damp and the passage of time has not been kind. These days it is becoming increasingly difficult to find crystal microphones that are still in working order. Even though later crystal microphones used ceramic materials such as lead zirconate and barium titanate which were somewhat more durable than Rochelle salt, the stock of working crystal microphones has been steadily dwindling. In the 60’s with the arrival of cheap, reliable, dynamic and electret-type condensers the crystal microphone was quickly superseded. 

During the 1950’s home tape recording became a popular hobby, and there was a super-abundance of budget machines aimed at the amateur recordist. Although some of the more upmarket models came with a dynamic microphone, most of these tape recorders were supplied with a cheap and cheerful crystal microphone…………… Which brings us to the Ronette ‘CORONATION 53’

CLICK LINK BELOW TO LISTEN.

The ‘CORONATION 53’ is a high impedance microphone and comes with a standard 1/4inch balanced jack.

To record my voiceover on the video I used an inline Hosa MIT-129 50k Ohms- 200 Ohm transformer which enables connection to an XLR mic input.

Ronette CORONATION 53 Advert and Tech Spec

Not perhaps the flattest frequency response graph, but nevertheless a bargain for the princely sum of 52 shillings! (20 shillings to the pound in 1953). Based on the Ronette 088-u7 ‘Soundball’ already in production, Ronette spared absolutely no expense in creating the ‘CORONATION.53’. A quick mod to the plastic moulding to create a short handle, and the words ‘CORONATION.53’ in small raised letters on the ball. Job done!  

Conclusion

BBC TV live coverage of the Coronation launched mass television viewing in the UK. Demand was so great that electrical shops everywhere sold out of TVs. Unlike today, the British royal family were at a high point of post-war popularity. Amidst all this flag-waving and razzmatazz Ronette saw a marketing opportunity. However, even in 1953, I really can’t imagine many people rushing out to buy a cheap, plastic, crystal microphone just because it called itself the ‘CORONATION 53’!

Ronette CORONATION 53 crystal microphone

Today they are somewhat rare. Until I bought this one I had never seen one before. However, in fairness to Ronette it does sound a lot better than I thought it would, and might still come in handy for something!

Ronette CORONATION 53 crystal microphone

And it is very shiny!

STC 4035 Omnidirectional Dynamic (Circa 1953)

STC4035

Designed in the early 1950’s and used extensively by the BBC, the STC4035 replaced the STC4017C which had been in service since 1938. Throughout the 50’s and 60’s the 4035, along with its Bakelite cousin the STC4032, were amongst the BBC’s primary outside broadcasting microphones. Apart from the casing and switching on the 4032 these two microphones were identical. Although both models had the same very effective wind resistant fine mesh grill, in the event of very high wind or rain the 4001.A. windshield could be added.

STC4032 and STC4035 with 4001 windshield
STC4035 with 4001A windshield
STC4017 compared to STC4035

The 4035 was much lighter and smaller than the old 4017, and although it was essentially omnidirectional there was some directionality at high frequencies.

Here is a full description and technical specification.

Below is a pricelist from the late 50’s.

N.B. In today’s money £18.10.0 would be around £520.00.

At the BBC the 4035 was used for a very wide range of tasks.

Big Ben

In the mid 50’s an STC4035 with a modified connector/mounting attachment was installed directly beneath ‘Big Ben’ in the Elizabeth Tower at Westminster. This was connected to BBC Broadcasting House and used to broadcast ‘live’ the world famous clock chimes of this huge, iconic bell. My Dad (along with the rest of the British population) always used to set his watch by the BBC chimes.

Horse Racing

In order to capture the exciting thunder of horses’ hooves and all the thrills and spills of the race, BBC Manchester Radio OBs used to place a 4035 in every jump for the Grand National.

Wimbledon.

1962. Interesting arrangement of two STC4035s with windshields.
(Photo IET Archives)

They were also used as general effects mics at many other sporting, and outdoor events, very often used to pick up atmosphere and the sound of the crowd.

Perfect for Political Speeches

British Prime Minister Harold Macmillan in 1957 (Photo BBC)
STC Dual stand for 4035

STC Dual stand.

ITV arrived in the mid-1950’s and also found plenty of use for the mighty 4035!

STC4035 in Grampian Parabolic Reflector
1967 Coltishall Airshow AngliaTV:  STC 4035 in a Grampian Parabolic Reflector. (Photo Dave Taylor).

I love the look of dedicated concentration, trying to focus the dish on high speed aircraft using only headphones!

STC4035 connection socket

The 4035 connection socket is the same as most STC microphones and requires the 4069A plug (which is still widely available).  Interesting to see the screw heads in this picture. These can be undone to separate the upper and lower halves of the microphone for repair. Normally they are covered with hard wax.

So……. What does it sound like?  CLICK HERE for audio clip.

Conclusion

If there was a competition for the world’s most boring looking, least stylish microphone, the STC4035 would definitely be in the running, with its dull grey/black finish and uninteresting shape. Also, unfortunately, unlike the ‘Apple and Biscuit’ STC4021 or ‘The Stick’ STC4037, the poor old 4035 doesn’t even have an amusing nickname! However, good looks aren’t everything and if you are simply looking for a robust ‘workhorse’ microphone with a reputation for being completely reliable, even in the most adverse conditions, then the STC4035 is definitely worth considering!

LABOR W MD7 Omnidirectional Dynamic Microphone Circa 1950.

A Short History Lesson.

In 1945, just a few weeks after the end of World War 2 Fritz Sennheiser and 7 fellow engineers from the University of Hanover set up a business designing and producing a range of electrical equipment in a laboratory called Laboratorium Wennebostel (“LABOR W” for short). The laboratory was named after the village of Wennebostel in the municipality of Wedemark, where it had been relocated during the war. LABOR W began building microphones in 1946 and by 1953 (see catalogue below) they had developed a whole range of microphones, including the legendary MD 21 which is still in production today. By 1955 the company had expanded to 250 employees and in 1958 changed its name to Sennheiser.  

These days microphones from the early LABOR W period are becoming increasingly rare, so when this unusual looking MD7H turned up on eBay, ‘untested’ but very cheap, I immediately clicked ‘Buy Now’.

LABOR W MD7H   front view
LABOR W MD7H  front view 2
LABOR W MD7H rear view
The ‘H’ indicates that this is the High impedance version.

The photograph on eBay however, gave no sense of scale and it wasn’t until the microphone arrived that I realised just how small it is! I was reminded of the anecdote of the person who buys a gorgeous sofa online at a bargain price and when it arrives it turns out to be for a dolls house! Had I seen the LABOR W advert below that might have given me a clue.

LABOR W MD7 Advert early 1950's
‘Our most powerful moving coil microphone
MD7 for speech’

Below are the microphones featured in the 1953 LABOR W Catalogue.

Microphones featured in the 1953 LABOR W Catalogue. Page 1
Microphones featured in the 1953 LABOR W Catalogue. Page 2

(Translation of catalogue description above)

‘MD7 Speech microphone

Particularly good speech intelligibility due to emphasis on high frequencies. Therefore recommended for announcement and dictation systems. The soft rubber housing makes the MD7 insensitive to rough handling. Available in low and high impedance versions.

Dimensions: 76 x 48 x 48mm.’

For a sense of scale here below is the baby MD7 along with its Senneiser cousins the MD21 , MD421 and the mighty MD441.

LABOR W MD7 along with its Senneiser cousins the MD21 , MD421 and the mighty MD441.

Innovative design

In the early 50’s the soft rubber housing of the MD7 was an innovative design feature, and indeed made it very robust and resistant to rough handling. I haven’t tried it, but I think it would probably bounce if dropped from a height! It therefore came as no surprise once I had soldered a jack plug on to the cable it burst into life working perfectly.

So what does it sound like? CLICK HERE

LABOR W production came to an end in 1958 and the name changed to SENNHEISER. The rest is history!

RSA Selmer RL1 Ribbon Microphone 1947-1958

Wireless world Advert October 1946

Looking back from the 21st century it is hard to picture a ‘dream’ PA system as being 2 x 8” speakers attached to a 12 WATT amplifier with 2 mic inputs!! However, in the UK this marks the beginning of the age of amplified, modern popular music. Within a few years the wattage and power output of PA systems would be rising rapidly, trying to keep pace with bigger and louder guitar amps!

In 1947 R.S. Amplifiers Ltd was bought by H. Selmer & Co Ltd who were at that time the largest musical instrument manufacturer in England. RSA’s newly launched Truevoice U12 PA system (described in detail below) continued in production until 1958 and formed the starting point for the Selmer Truevoice range of amplifiers. Selmer amps soon became a firm favourite for a whole generation of guitarists and bands.

R.S.A Selmer U12 PA system
Photographs of U12 PA Courtesy of Mario Martins.
R.S.A Selmer U12 PA Amplifier
R.S.A Selmer U12 PA Speaker with Mic compartment.

The handy compartment lined with green baize is where the microphone would be stored in transit.

The RSA Selmer RL1 Microphone

R.S.A. Selmer RL1 Ribbon Microphone.

Designed as a gigging PA microphone the body of the R.L.1. is very solidly cast in aluminium. The styling is distinctive and unusual. Somewhere between Art Deco and Mock-Tudor!  I can’t think of another microphone like it. The design of the grill is also peculiar to this model (and the later RL2) with baffled slots cleverly contrived to prevent the direct implosion of breath on the ribbon.

Inside the R.L.1. the ribbon motor is also further protected by a cotton bag.

R.S.A. Selmer RL1 Ribbon Microphone Interior.
R.S.A. Selmer RL1 Ribbon Microphone Interior case.
R.S.A. Selmer RL1 Ribbon Microphone Grill Interior.
R.S.A. Selmer RL1 Ribbon Microphone Rear View..

Optional step-up transformer 15 Ohms – 50k Ohms (below)

 This enabled the mic to be plugged into a high impedance PA input or even a guitar amp.

R.S.A. Step-up Transformer 15 Ohms- 50k Ohms.

Performance.

In terms of performance the R.S.A. Selmer RL1 is pretty much what you would expect from a ribbon microphone designed to go with the U12 PA system. Although it is somewhat lacking in high end response this would not have been a problem when delivering through 2 x 8 inch speakers! However, it has a pleasing, warm midrange which is flattering for most vocalists.

I had been intending to record a vocal clip to illustrate the qualities of this microphone but current COVID-19 restrictions here in the UK still make it difficult to meet up with performers. Hopefully in the next few months this situation will improve and I will be able to add a suitable recording to complete this post. 

P.S.

Here are a couple of likely lads from Liverpool (circa 1960) with the Selmer RL2. The grill is identical to the RL1 but the bodywork is somewhat different. I wonder what ever happened to these fresh-faced youths?

Tannoy Microphone Circa 1950.

Background.

The Tulsemere Manufacturing Company was founded in London in 1926 by Guy R. Fountain. In 1928 the name was changed to Tannoy. Rectifiers used in the company’s amplifiers utilised an alloy made from lead and tantalum. The name is simply a contraction of TANtalum/allOY.

 In the UK throughout the 1930’s Tannoy built up a considerable reputation for the design, manufacture and installation of industrial public address systems. Tannoy systems appeared in department stores, factories, offices, public buildings, academic institutions and sports grounds. In fact, just about anywhere that public announcements needed to be made- indoors or outdoors. There were even mobile systems fitted to vans!  

During World War 2, Tannoy manufactured installations for the British Army, Navy and Royal Air Force. Orders and day to day communications would be announced over ‘the Tannoy’.

By the end of WW2 the Tannoy brand was pretty much synonymous with any PA system. In 1946 the word ‘Tannoy’ passed into the Oxford English Dictionary as a noun meaning ‘public address system’. This usage is still current in the UK today.

As can be seen on the microphone featured here, Tannoy were not shy when it came to emblazoning the company name on their products. Judging from the tasteful antique bronze and grey paint finish, this gooseneck announcement microphone may well have been mounted on a mahogany desk in a Town Hall or other municipal building.

At first glance I assumed that this specimen, which has no model or serial number on it, was simply a dynamic paging mic in a fancy-looking case. However, when plugged in I was very surprised to hear how good it sounded! I carefully removed the grill and inside this is what I found……………

……. A well-made and neatly constructed, end addressed, ribbon motor. The back of the ribbon is enclosed by the magnet and the rear section of the casing. This produces a pretty much cardioid, directional polar pattern. It is similar in design to the STC4113 featured in a previous post.

So what does it sound like?   Because, here in the UK we continue to be under COVID-19 lockdown restrictions I still can’t get close to any proper musicians. I have therefore put together a slightly eccentric audio ‘collage’ of ‘percussion’ from around my desk to illustrate some of the impressive qualities of this distinctive Tannoy microphone. Marvel at the slightly sinister sound of 2 small terracotta plant pots being rubbed together and check out the creaky floor board! The finest details and complex textures of a variety of sounds are effortlessly reproduced as well as delivering natural speech with a high level of intelligibility.  

 CLICK HERE TO LISTEN.  

Conclusion.

This is definitely a microphone to keep. Apart from vocals and percussion, I have a feeling that it will work well on a whole range of instruments. Ribbons are always great for beefing up guitars! Can’t wait to get back to gigs and try it out!

Tannoy Mic on Rycote shock mount.

P.S.  

Here below are a couple of photos of another Tannoy microphone sent to me by Stewart Tavener at http://xaudia.com/. This mic appears to share the same casing and ribbon motor as mine but has a switch and hinged stand mount.

American Microphone Company D9A/ D9AT ‘Skyscraper’ (1938- circa 1958)

American D9AT Where's Wally

Where’s Wally/Waldo?

When the American D9A was launched in 1938 it was notable because of its fashionable Art Deco ‘look’ inspired by the skyscraper skyline of New York and other great American cities. Indeed the side elevation of the mic appears to directly reference Manhattan’s famous Chrysler Building constructed in 1930.

American D9 Side View Chrysler Building

This was the age of Jazz, and Rock’n’Roll was just around the corner. Microphones increasingly appeared centre stage in photographs and on screen as part of the performer’s visual image. Over the following couple of decades the American Microphone Company kept ahead of the game producing a number of stunning designs which appeared in movies and featured in commercials.

Katharine Hepburn, Spencer Tracy, Van Johnson, and Angela Lansbury in State of the Union (1948)Katharine Hepburn, Spencer Tracy, Van Johnson, and Angela Lansbury in State of the Union (1948)

The transducer design of the American D9 is also interesting and unusual.

The D9A /D9AT is often incorrectly identified as a ribbon microphone! This matter can simply be resolved by undoing 4 screws!!American D9AT Interior Front viewAmerican D9AT Rear inside viewAmerican D9AT Interior side view

Does this look like a ribbon motor??!!  In the advertising blurb below it is described as being ‘a pressure-velocity combination microphone’ which may have led some folks to think that the ‘velocity’ element must be a ribbon (like the Western Electric/Altec 639). However, the 2 elements are clearly both dynamic. One pressure element (omni) sealed at the back, and one velocity element (Fig of 8) open at the back. The signals from these 2 elements are combined to produce a cardioid directional response. I can’t off hand think of another microphone that is configured in this way using 2 separate dynamic elements.American Microphone Company D9 Advert

Although I can accept most of the description given above, the notion that the DA9 has ‘qualities of ruggedness’ is somewhat farfetched. Sadly, the bodywork appears to be cast in a cheap zinc alloy which is brittle and easily damaged. The yoke is also made of the same material. These days it is hard to find one without bent, cracked or broken ribs.American D9AT Damage to bodywork

Some years ago I was working on a theatre show in which an over-excited actor, (playing the part of Jerry Lee Lewis) unintentionally launched my treasured Electro-Voice EV664 right across the stage. It landed 30 feet away with a sickening thud. Apart from a slightly damaged switch the mic was unmarked and still worked perfectly! That is rugged! I wouldn’t want to try that with my D9AT. This is definitely not a mic to drop by accident. As well as the fragile body the chrome plating is remarkably thin. Even though my D9AT is from the tail end of production in the mid 50’s much of the chrome has worn away. Nevertheless it is still a stylish looking object.American Microphone Company D9AT

BUT………….. More importantly what does it sound like?  CLICK HERE for Voice Recording

The American Microphone Company D9A / D9AT was not designed as a high quality studio instrument. It was recommended for P.A. and installation use. In 1938 most dynamic P.A. mics were feedback-prone omnis. American’s dual element cardioid with its promise of higher gain before feedback could therefore be seen as an exciting new development. However, the following year Shure launched their game changing Unidyne 55 featuring a single cardioid capsule. The new single capsule design was soon adopted by most manufacturers as it was clearly cheaper to make and capable of producing excellent results. American carried on manufacturing the D9A/ D9AT for another 15-20 years. In 1955 the company was bought by Elgin-Neomatic,Inc. whose main business was watch making. At the time Elgin had the notion that they would develop miniature parts for microphones but this idea soon faded. My D9AT featured here is from the Elgin period.Badge ELGIN American Microphone Company D9AT

Around 1960 American was sold again to General Cement Company Rockford, Il (AKA G.C.Electronics). Several years later the company was finally bought by Electro-Voice who soon retired the brand.

In Conclusion

Although the American Microphone Company D9A/AT may not win any prizes for its audio quality it nevertheless provides an interesting link in the development of directional microphones in the first half of the 20th century.

Steane’s ‘Ellipsoid’ Ribbon Microphone Circa 1948. A Sorry Tale!

Steane's 'Ellipsoid' Ribbon Microphone circa 1948

Steane’s ‘Ellipsoid’ was a budget ribbon microphone made in Melbourne Australia in the late 1940’s. The advertising literature from December 1948 declares it to be the ‘World’s Smallest Ribbon Mike’!Steanes-1948-advert

Other claims made in the blurb also raised my curiosity, especially the bit about ‘No boom or puff’!  (Never previously on my list of ribbon mic problems!)   So when my newly purchased Steane’s ‘Ellipsoid’ arrived I had to plug it in straight way. However………….. As I turned up the volume on my headphones I was horrified by the sound that assailed my ears. It had a very unpleasant nasal honk and a gratingly harsh high end! This was not what I was expecting! The previous owner had assured me that this shiny gem was fully working and all original. Hmmm!

On opening it up this is what I found. Whaaaaaaaaat TF!

Astatic MC-127

The ribbon motor and transformer had been removed! The body of the mic was filled with grotty, yellowing, wading and a crudely soldered Astatic ceramic element dumped unceremoniously on the top.The whole horrifying confection was sort of held in place with a couple of random bits of grey foam.

Astatic MC-127 back view.

The grill was also stuffed with wading to stop the lose element from rattling around (and maybe improve the tone?) Perhaps it was an attempt to get rid of some of that legendary Aussie ‘Boom’ and ‘Puff’!   Anyhow, I sadly stuffed it all back together as I found it and bunged it back in the post to the previous owner for a full refund. What a disappointment!

P.S.

If like me you are unfamiliar with Steane’s microphones here is their Microphone catalogue circa 1948/9. The mics listed here offer a range of applications for both the professional and the amateur user. I notice that the Dynacard model also guarantees ‘No Boom or Puff’!  🤣  The Home Studio shown on the last page is interesting as it appears to be an early form of Karaoke system allowing the user to sing along with the radio and thereby add ‘zip’ to any party!

Steane's Microphone Catalogue 1948/9 Steane's Microphone Catalogue 1948 P.1 Steane's Microphone Catalogue 1948 P.2 Steane's Microphone Catalogue 1948 P.3 Steane's Microphone Catalogue 1948 P.4 Steane's Microphone Catalogue 1948 P.5 Steane's Microphone Catalogue 1948 P.6

Anyhow, perhaps one day another Steane’s microphone will come my way.

Martin Mitchell’s Music For 3 Saucepan Lids and Spatula ! Recorded by the Gaumont-Kalee Type 492. 😊

Inspired by washing up! I did this recording for a bit of amusement on a cold rainy Saturday morning (crazy sound engineer’s idea of having fun!) ……… but I really love the way this beautiful old ribbon mic reproduces the ring and detail of these sounds. I suspect that the 492 would also make a great drum overhead. Anyhow, enjoy!

Gaumont-Kalee Type 492 Ribbon Microphone (Circa 1950) A rare piece of British cinema history.

Gaumont-Kalee Type 492 Side viewGaumont-Kalee Type 492 Side view2Gaumont-Kalee Type 492Gaumont-Kalee Type 492 Box

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.Gaumont-Kalee Portable Recording Equipment

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.Gaumont-Kalee Type 492 inside 1Gaumont-Kalee Type 492 inside 2
  • 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.Gaumont-Kalee Type 492 inside 3Gaumont-Kalee Type 492 inside 4
  • 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.

 In Conclusion.

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!

GB-Kalee 1950 Catalogue. Cover

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 !)

 


Gaumont-Kalee Catalogue Page 4

Useful Links.

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.

1962 BBC Training Manual

In the 1951 BBC Microphones training manual we saw that the corporation functioned with a small selection of British manufactured microphones, most of which had been in service since the 1930’s.  So when I saw this Manual from 1962 I was curious to see how ‘Auntie’ had moved on into the swinging sixties.

BBC Training Manual 1962

Old favourites continued in use.                                                                                         BBC Training Manual 1962 STC Dynamic Microphones

The STC4021 ‘Apple and Biscuit’ first appeared in 1935 as did the famous Marconi A series ribbon microphone pictured on the page below. (The AXBT is the 4th generation).  The STC4035 was a lighter, updated replacement for the old STC 4017, which had been phased out in the mid 50’s. The 4032 is identical to the 4035 but housed in a neat handheld Bakelite body making it suitable for outdoor use in all weathers. The 4037 was designed for TV and has a rather more modern look (slim lightweight body and matt black finish). However, the capsule is still pretty much the same as the good old ‘Apple and Biscuit’. STC’s dynamic models were the tried and tested backbone of general purpose and outside broadcasting. The noise-cancelling STC4104 lip ribbon mic was used for sports commentary and noisy events. This was an updated version of the older Marconi lip ribbon microphone. More recently manufactured by Coles, the 4104 continues in production to this day.

BBC Training Manual 1962 Ribbon Microphones

So what was new?

FM broadcasting by the BBC began in 1955 and the audio frequency response was thereby extended from 5 kHz up to 15 kHz. The new FM system was also considerably less susceptible to noise and interference than AM. Although the old favourite microphones from STC and Marconi were still fine for everyday transmission of speech, when it came to the broadcasting of high quality music, mics with improved high end response were now required. With this in mind the BBC Research Department designed 2 new ribbon microphones (pictured above). First came the PGS (Pressure Gradient with a Single magnet) and from this developed the 4038. Manufactured by STC these new microphones were considerably smaller and lighter than the old Marconi AXBT, and had an almost flat frequency response up to 15 kHz. This was around ½ an octave higher than the mighty AXBT. Now manufactured by Coles the 4038 continues in service to this day and is still recognised as one of the finest ribbon microphones available.

The photograph below is rather bizarre. In real life the STC4033 is around 3x bigger than the Reslo! The Reslo was small and convenient for use on TV (as mentioned in my previous blog post). The STC4033 is an unusual hybrid, similar in design to the classic Western Electric 639 ‘Birdcage’. It has an ‘Apple and Biscuit’ type omni dynamic element, and a ribbon element. This gives a choice of switchable polar patterns. Using the elements separately we have Omni or Figure of Eight and by combining the outputs of both we obtain Cardioid. Nevertheless, by 1962 the STC4033 was a somewhat antiquated design and no match for the more sophisticated competition coming out of Germany and Austria.

BBC Training Manual 1962 Reslo and STC4033

Enter AKG and Neumann……….

A number of high quality condenser microphones now appeared in the BBC microphone locker. The legendary AKG C12 quickly became a firm favourite for the broadcasting of concerts and was very often the only microphone used to capture a symphony orchestra in glorious Mono! The AKG C28, C29 and C30 were perfect for solo performers on live TV. The variable extension pieces made it easy for unobtrusive positioning.

BBC Traing Manual 1962 AKG C12.jpgBBC Traing Manual 1962 AKGC28 .jpg

The Neumann KM54 cardioid, and the multi-pattern KM56 were also popular choices for high quality broadcasting.

BBC Training Manual 1962 Neumann KM54BBC Training Manual 1962 Neumann KM56

Other Microphones.

A number of other microphones are given a mention but not honoured with a photo. The Corporation was still very much dominated by BBC Radio and most of these microphones are from the rapidly evolving new world of BBC Television. TV presenters very often needed to keep their hands free and microphones ‘in shot’ needed to be small and unobtrusive.

BBC Training Manual 1962BBC Training Manual 1962BBC Training Manual 1962

The Placing of Microphones
The diagrams and explanations on the pages below provide an interesting insight into the lost world of recording and broadcasting in Mono.

BBC Training Manual 1962 Microphone Placement 01

The BBC philosophy for the broadcasting of classical music is best summed up in the opening sentence of the page below.  In the manual there is a clear distinction between music which requires the engineer to simply reproduce a ‘true balance’ created by the conductor and the performers (captured by one microphone), and more popular forms of music which require the engineer to create the balance from a number of microphones. Today this distinction has been all but lost.

BBC Training Manual 1962 Microphone Placement 02BBC Training Manual 1962 Microphone Placement 03

 Modern Dance Bands

BBC Training Manual 1962 Microphone Placement 05

Setups for Dance Bands.

BBC Training Manual 1962 Microphone Placement 06BBC Training Manual 1962

The section above on Modern Dance Bands contains no mention of the latest Beat Groups, Rock’n’Roll or Skiffle. BBC thinking was clearly lagging at least 5 years behind the latest trends in popular music. If you were a teenager in 1962 the ensembles mentioned above are the sort of music your Mum and Dad would have liked! Within a couple of years British teenagers were under the bedclothes every night with a transistor radio listening to their favourite music coming from pirate radio stations such a Radio Caroline and Radio London, illegally broadcasting from offshore. It wasn’t until 1967 that the BBC threw in the towel and set up Radio 1 to cater for a younger audience!

STEREOPHONY

The final chapter of the manual is devoted to describing the basic principles of ‘STEREOPHONY’. Even though stereophonic records had been around for several years, by 1962 stereo broadcasting was still in it’s infancy. Around this time there were a number of experimental BBC broadcasts. In our house I can remember my Dad following the instructions for a particular broadcast by setting up 2 radio sets tuned to different programmes, one carrying the left-hand channel and one carrying the right !! Unfortunately the 2 radios were very different sizes and so the effect was somewhat less than perfect! It was not until 1973 that Radios 1,2 and 4 finally broadcast in stereo.

In Conclusion.

Although a small amount of space is given to sound in the context of television, this manual is firmly focused on ‘High-Quality Sound Production and Reproduction’ for BBC Radio. Tape had pretty much replaced 78 rpm discs as the primary means of recording and storing programmes. FM broadcasting was a huge technical leap forward and the arrival of some new condenser microphones further improved the quality of the output. Nevertheless, in many respects, even by 1962 ‘Auntie’ still had one foot firmly in the 1930’s !