Tag Archives: Vintage Microphone

BBC Engineering Training Manual. MICROPHONES. (1951)

I was born on January 20th 1951 at St Mary’s Hospital for Women and Children in the centre of Manchester,  just across the road from the Palace Theatre. Less than a mile away, at the BBC Studios in Piccadilly, engineers were avidly thumbing through their copies of the very latest BBC ENGINEERING TRAINING MANUAL . MICROPHONES!

BBC Training Manual 1951

My copy arrived yesterday! (courtesy of eBay). It is in nearly new condition and sadly it’s unmarked pages have all the ‘vibe’ of a book that has never been read!

In recent years I have often regaled students with my reflections on how much audio technology has changed during my lifetime. Reading through this book really brings it home! It is a window into a long-gone world of engineers in brown lab coats and announcers at the microphone in evening dress. For me, as a child, it was the world of ‘Listen with Mother’ and ‘Children’s Hour’ and seeing the valves glowing in the back of the mahogany veneered wireless set on a shelf next to the fireplace in our living room.

My earliest memory of a microphone was standing on a box in front of a huge Marconi AXBT ribbon mic having won a prize in a BBC Children’s Hour competition at the age of 7 or 8. (It looked just like a giant ice cream cone!) I was presented with a silver propelling pencil by the producer Trevor Hill. I said ‘Thank You’ in the general direction of the mighty Marconi, and was escorted back to my seat.

BBC Children's Hour Competition Prize 1958


Anyhow, back to the book. 

What is most striking is how slender this volume is (114 pages). Most of it is taken up with detailed information about the propagation of sound and the physics involved in microphone design and construction. Much of this is still useful knowledge. However, only 7 different microphones are described in detail and most of these had already been in service since the mid 1930’s.

Here, (to give you a flavour of this informative little book) are some of the illustrations.BBC Marconi Ribbon Mic

In the BBC Studio of 1951 the Marconi AXBT Ribbon Microphone (first introduced in 1935) was the principal tool for drama, announcement and music. Broadcasting  was in Mono. With a frequency range from 20Hz-16 kHz, this figure of eight device was very often the only mic used!  One useful piece of advice offered to the engineer, in order to avoid ‘an excessive bass response’ (caused by proximity effect), is that ‘The microphone should never be used at a distance less than approximately two feet.’


BBC STC4017C

From 1938 to 1953 the STC 4017C was the main BBC outside broadcast microphone. Built like a tank, with a solid copper body and an aluminium diaphragm, it was a very robust dynamic. Although, in theory omnidirectional, it did exhibit some frontal directionality at higher frequencies.


BBC STC4021

The STC4021 , nicknamed the ‘Apple and Biscuit’, was a high quality dynamic mic which, due to its spherical shape, was truly omnidirectional. It was mounted vertically and was used for a variety of purposes including ’round table’ discussions and interviews. It was also used as a talkback mic.


BBC EMI Moving Coil

Developed by Holman and Blumlein working for the Columbia Gramophone Company (later E.M.I.) , it was used extensively by the newly formed BBC Television service at Alexandra Palace from 1936.The unusual thing about this microphone is the fact that it’s diaphragm is made of thin balsa wood enclosed between two sheets of aluminium foil! Interestingly, the description in the book ends with something of a warning……..  ‘the instrument is less suitable when high quality is a major consideration’  !!!!!


BBC Marconi Condenser Mic

BBC Marconi Condenser Element

The Marconi Condenser Microphone with built-in amplifier was a large and extremely rare beast, introduced experimentally in the mid-1930’s.  Even at the BBC it was not commonly used. Early condensers were prone to suffer with crackling caused by moisture.When it was employed it was mostly to be found at concerts.


BBC Brush Crystal Mic

BBC Brush Sound Cell

I have never seen a BBC studio picture with one of these. Not sure what it’s duties might have been. Perhaps, included in the manual simply because it is an example of a crystal mic? These were quite common at the time as PA and announcement mics. Also quite popular with amateur tape recordists.


BBC Marconi Lip MicBBC Marconi Lip Mic Back view

The Marconi Lip Ribbon Microphone (designed by the BBC in 1937) is a noise cancelling device which was used for sporting commentaries and broadcasting in noisy environments. It was designed for very close speaking with the ribbon protected from the impact of the speaker’s breath by the enclosing magnet. (see pics above)  One of the most important features of this microphone is the mouth-guard, which is pressed up against the speaker’s jaws, thus maintaining a constant distance between the mouth and the ribbon. This ensures against changes in frequency response, and volume, caused by fluctuations in distance. A variation of this microphone is still made today for the BBC by Coles (formerly STC).

BBC Training Manual 1951012BBC Training Manual 1951013

Foot Note.

In 1953 BBC Television broadcast live the Coronation of Queen Elizabeth II. Amongst the most notable features of this historic broadcast was the commentary delivered by Richard Dimbleby inside Westminster Abbey. The microphone used on this occasion was the latest Marconi L.2 Lip Ribbon mic. The perfect choice! The closeness of the speaker to the microphone, and the rich tone of Dimbleby’s voice, served to give the listening audience an intimate, sense of the grandeur of the occasion. The isolating characteristics of the lip microphone also served to focus attention on his voice. Dimbleby was the undoubted master of this technique of close-mic’d delivery which became a hall-mark of British State occasions.

Richard Dimbleby at the Coronation of Elizabeth II 1953

Richard Dimbleby with the Marconi L.2 Lip Ribbon microphone in the specially constructed commentary box in the Triforium of Westminster Abbey


 

In Conclusion

Within a decade of this manual the BBC microphone cupboard would be rapidly filling with exciting new models from the likes of AKG, Sennheiser and Neumann. In the following years alongside the growth of television and multi-track recording came a whole range of microphones designed for different purposes. Stereo mics, shotgun mics, lavaliers, parabolic, contact, binaural, ambisonic…………….. A whole new world!


Here are some useful links for more information.

http://www.coutant.org/bbc/index.html   (Some great photos of the Marconi Ribbon Mic)

http://www.coutant.org/marconi/    (Pictures and information on this extremely rare condenser mic)

https://martinmitchellsmicrophones.wordpress.com/2013/06/21/stc-4017c-dead-or-alive/

 

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Shure 430 ‘Commando’ Controlled Magnetic / Controlled Reluctance Microphone (Circa 1957)

Shure Model 430 CommandoShure 430 Commando grill

The Controlled Reluctance microphone (aka Controlled Magnetic) was developed by Shure during World War 2 to fulfil the need for a battle announce microphone that could operate reliably at extremes of temperature and humidity. (Subsequently also perfect for Korea and Vietnam!)

Although the Controlled Reluctance design was in some respects similar to a conventional dynamic in other ways it was significantly different.

The 2 diagrams below illustrate the differences.

  • DYNAMIC MICROPHONEDynamic-moving-coil-diagram
  • CONTROLLED RELUCTANCE/MAGNETIC MICROPHONE (2 slightly different versions)Controlled Reluctance Microphone Sectional Diagram

Here, in response to an email enquiry, is an explanation from Shure of the working of this microphone

On 3 May 2017 15:06, “Shure Europe” <support@shure.eu> wrote:

Response By Email (Michael P) (05/03/2017 09:06 AM)

Controlled reluctance is a variation of a dynamic mic.  The controlled reluctance mic diaphragm connects to a small lever made from ferrous material.  The other end of this lever is positioned inside of a stationary coil of wire.  Surrounding the coil of wire is a stationary magnet.  As the ferrous lever is moved by the mic diaphragm, the lever disturbs the magnet field.  This induces an AC signal (the audio signal) in the coil of wire.

Answer Link: Difference between controlled reluctance and controlled magnetic

This type of mic was originally designed for military applications.

Michael Pettersen

Shure Historian

 


2 pin Ampenol Connector

If you buy a 430 make sure it comes with one of these as 2 pin Amphenol connectors are hard to find.

The CR/CM elements have a high output (making them suitable for transmission over large distances) and require no additional transformer. They are therefore cheaper to manufacture than a conventional dynamic.

After WW2 Shure introduced several models for the civilian market, including the famous Green Bullet (still popular with harmonica players to this day). These were mostly budget PA mics intended for speech applications such as paging and announcements. Whilst not being particularly noted for high quality audio, their main selling points were cheapness and reliability. It is therefore not hard to see why these sturdy, affordable mics soon found favour with musicians and singers.

Apart from being highly profitable, Shure’s military communications contracts had the additional spin-off of enhancing a lasting reputation for reliability. Indeed, the company have often boasted that all of their products are tested to military standards (MILSPEC).  Even though the Model 430 was made for the civilian, domestic market it nevertheless trades on its military heritage with the name ‘Commando’ and it’s distinctive, camouflage green head!

Shure 430 Commando head

Data Sheet for the Shure Commando series.:-     us_pro_415_ug

Shure Microphones  :-  1957 Catalogue

 430 Commando Original Box

So what does it sound like?  CLICK HERE for a short clip of spoken word and Blues Harmonica.

 

Electro-Voice EV642, 643, & 644 Cardiline Microphones , (circa)1960

Ever since the advent of the ‘Talkies’ sound technicians have struggled to pick up speech in motion pictures with sufficient clarity. For many years the problem of getting the microphone close enough to the performers without it being in the camera shot was a constant challenge!  On the other hand if the mic was too far away the sound was often ruined by the pickup of unwanted surrounding noise.

Seeking to address this problem, in October 1959 Wayne A. Beaverson of Electro-Voice filed for a patent on a new type of directional microphone which could be successfully operated at a distance from the sound source.  At low frequencies this microphone exhibits the directional characteristics of a cardioid mic, with excellent rear rejection. As the frequency response rises it becomes a line mic with considerable attenuation of unwanted sound from the sides. Thus the new ‘Cardiline’ design provides excellent directivity right across its operating frequency range.

Electro-Voice Patent for Unidirectional Microphone 1963

The success of the new microphone was such that in 1963 Electro-Voice received an Academy Awards “Oscar” for the development of the model 642 Cardiline, The award, in part, read “To Electro-Voice for a highly directional dynamic line microphone… capable of picking up sound in situations where a microphone cannot be placed close to the sound source and where unwanted sounds are to be discriminated against.”

Although the Academy Award went to the 642, the microphone drawn and described in the original patent application was in fact its close cousin the EV644. At this point you might be wondering about the 643?  Well ……… The 643 was pretty much the same as the 642 except in one significant detail ……… it was just over 7 feet long!  All three of these mics were of the Cardiline pattern but they were aimed (excuse the pun) at different areas of the market. As we know, the 642 was tailored very much for the film and TV industry and came with an elastic mount for attaching to a boom.

EV642 Advert 1963

EV643  Advert

Electro-Voice_643 Advert

electrovoice_643_2

Although extravagant claims are made for the mighty 643 in the advert above, I suspect that this mic was in fact quite awkward and unwieldy to use (even sighting along the barrel!!) It is certainly hard to find any fond recollections of it. I came across one report from some poor sod who once spent an afternoon standing on the roof of a football stadium trying to follow the ball round the field!! Anyone who has ever operated a theatre follow spot will appreciate just how ludicrous that must have been!

Which leaves the 644. (My latest eBay bargain!)

electro-voice-ev644

Designed for use on stage, in theatres, auditoriums and churches,  the EV644 Sound Spot came with a microphone stand mounting and was finished in classic Electro-Voice chrome. You could also buy it with a dull matt paint finish,(non-reflective under lighting), but why do that when the chrome version just looks so rock’n’roll cool !

Allied Catalogue 1960

List Price $110. A bargain at $64.68 ! (Not cheap in 1960!)

ev644-back-end ev644-body-and-stand-mountev644-end-grillev644-original-box-insideev644-original-box

CLICK HERE for Voice recording at a distance of 12ft

CLICK HERE for Glockenspiel Recording

In Conclusion

The 1963 patent shown above acknowledges a number of earlier inventions relating to directional microphones. In particular the patents of Harry Olson dating back to 1939. However, the earlier inventions, (mostly involving complex arrangements of multiple tubes of differing lengths), were awkward and cumbersome. In contrast, Beaverson’s Cardiline microphone, using a single multi-path tube feeding a single cardioid capsule, was an uncomplicated work of genius. It was both effective and easy to use.

To this day the elements of Beaverson’s patent can to be seen in shotgun microphones all over the world.

Below are the Techincal Specification Sheets for all 3 microphones.

Electro-Voice 642 Spec Sheet

Electro-Voice 643 Tech Spec.

Electro-Voice 644 Tech Spec

Grampian DP4 (circa 1963) A trip down memory lane!

It was the mid 1960’s and I was a teenager at school in Manchester. Only 30 miles from Liverpool. Before the age of discos. It was a fantastic time for live music. The Mersey boom was at its height and the pubs and clubs were rocking to the latest beat groups. (It is worth noting that none of the music clubs such as The Cavern in Liverpool, or The Twisted Wheel in Manchester, were licensed to sell alcohol. Nevertheless on a Saturday night their subterranean vaults were crammed with teenagers who had often queued for hours to see their favourite bands!)

In the 5th form some of my school mates formed a group. I used to lig along to their rehearsals in the school music room. They had a couple of Vox AC30 guitar amps and an old Selmer which was used for PA. I can remember the singer turning up one day with a very shiny new microphone. All black enamel and chrome, like the headlamp on a classic British motorcycle.Grampian DP4  Removed from it’s bright blue box the mic was duly plugged into the Selmer amp. The lads then launched into their version of Buddy Holly’s ‘Peggy Sue’. The assembled hangers-on (including myself) thought it sounded amazing!

I was therefore overjoyed a few weeks ago when a friend kindly gave me this bright blue box. I recognised it straight away!Grampian DP4 Box

Grampian DP4 with clip

Just below the chrome bezel there is a ribbed rubber ring designed to prevent the mic rolling off flat surfaces. Brilliant feature!

If you buy a DP4 make sure it comes with the 2 pin mic connector as these are as rare as hen's teeth!

If you buy a DP4 make sure it comes with the 2 pin mic connector as these are as rare as hen’s teeth!

Grampian DP4 Label

Here in the UK although the Grampian DP4 enjoyed a good deal of popularity as a PA microphone, and also with amateur tape recording enthusiasts, it was never really thought of as a top quality professional instrument. Sennheiser had launched it’s superb MD21 in 1953 and followed it in 1960 with the MD421.  Around the same time AKG gave us the D19 and the D24. The poor old Grampian was not quite in the same league. However, for a while the DP4 was used by the BBC for outside broadcasts and by their Wildlife Department in conjunction with the Grampian Parabolic Reflector. (As seen on the front cover of this issue of Tape Recording Magazine from 1969 )

tape-recording-uk-1969-04

A few weeks ago on TV I saw an old film clip featuring an impossibly young David Attenborough in the middle of the jungle somewhere clutching a Grampian Parabolic reflector with a DP4 mounted on it.

In the end Grampian Microphones were no match for the German. Austrian and American competition. As the 1960’s rolled on bands got louder, PAs got bigger, stage monitors were introduced and the omni-directional dynamic microphone fell out of use. Cardioids simply had more gain before feed back! By the mid-1970s the Grampian DP4 had disappeared from the stage and eventually the company went out of business.

So what does it sound like? 

 CLICK HERE for a short vocal trip down memory lane!

 

Grampian Brochures and Technical Information (These came in the box with my DP4.)

grampian-dp4-page-1grampian-dp4-page-2grampian-dp4-page-3grampian-dp4-page-4

grampian-dp4-instruction-sheet-page-1028grampian-dp4-instruction-sheet-page-2030

Electro-Voice Rags To Riches. T45 Noise-Cancelling Microphone (1944)

In 1942 after America entered World War 2, the US military estimated that only 20% of radio communications in combat were successful. Failure in the other 80% was mainly due to the voice of the radio operator being drowned out by the surrounding cacophony of war. Like no other conflict before, success on the battlefield relied on communications. Spotting a gap in the market Al Khan and Ed Burrows, the owners of Electro-Voice, came up with a brilliantly simple, ingenious and cost effective solution to this problem. Electro-Voice T45 Box

Electro-Voice T45 Instructions 1944

Electro-Voice T45 Instructions P2Even in 1942 the single button carbon microphone was a piece of old fashioned tried and tested technology, having been in use in telephones since the tail end of the previous century. Although the audio quality of the T45 is little better than it’s telephonic predecessors it is extremely reliable and very robust. It also has a high output making it ideal for long distance communication. Even if the microphone gets wet you can simply dry it out (as per the instructions above) and it will carry on working! However, the really clever part of this design utilises 2 small holes of equal size on the front and back of the mic.Electro-Voice T45 Back hole.Electro-Voice T45 Front Hole

These allow the surrounding noise to enter the microphone on both sides of the diaphragm. The sound striking the back of the diaphragm is 180 degrees out of phase with the sound at the front. This causes a very impressive cancellation of the unwanted noise whilst the speaker’s voice, which is less than a 1/4 of an inch from the front opening, dominates the transmission.

In terms of manufacturing costs it would be hard to produce a cheaper microphone.  A carbon button is a very small tin of glorified coal dust (carbon granules) with a simple diaphragm attached.  A bit of wire and some lightweight plastic fittings and that is it! Pure genius !Electro-Voice T45 Noise-cancelling Microphone

After some initial military skepticism the product was thoroughly tested and a first order came through to Khan and Burrows  for 100,000 units! The T45 was soon taken up by all branches of America’s armed forces and  the success rate of combat communications rose to 90%.

Rags to Riches.

Prior to World War 2 Electro-Voice was a small struggling company, with 20 employees, manufacturing a handful of dynamic and velocity microphones per week. By the latter part of the war Electro-Voice had 500 employees working in 3 shifts  producing more than 2,000 T45 microphones a day! After WW2 it was also adopted by commercial aviation and remained in service for several decades.  The T45 was also used on the Mercury, Gemini and Skylab space missions.

Over the entire production run more than a million were produced placing the T45  among the highest selling microphones ever made.

During the war many small firms went out of business due to a shortage of manpower and materials, but for those involved in the war effort fortunes were to be made. In 1946 Electro-Voice moved into an impressive new factory at Buchanan Michigan where they continued to manufacture  innovative and exciting audio products  for the next 60 years.

 

Footnote 

Circuit for powering a carbon microphone.  Circuit for powering Carbon Microphones.

 

STC4113 Cardioid Ribbon Microphone (c.1967) Restoration

STC4113 Before Restoration

I have recently been generously given this STC4113 cardioid ribbon mic which is rather in need of some TLC. The socket on the bottom is badly damaged and I don’t even know if it works. I think that it will make a nice little restoration project. However, as yet, I haven’t fathomed out how to take it apart!

The 4113 was designed by Michael Gayford (STCs chief designer) who was also responsible for the 4104 noise-cancelling lip mic, and played a key role in designing the famous BBC / STC4038 which is still made by Coles today.stc-advert-1968

In today’s money 11gns (ie £11.11s) is worth about the price of a Shure SM58

Although it was the cheapest of STCs microphones the 4113 features an unusual and innovative design and Gayford’s  patent (filed in 1963) makes interesting reading.

Michael Gayford’s Patent for the STC4113

The plastic horn arrangement used in this mic to create a cardioid polar pattern appears to be somewhat similar to the one that is to be found in the Beyer M260.  In both mics the plastic horn causes a shift in the phase relationship between the front and rear of the ribbon thereby modifying the polar pattern from the usual figure of eight to hypercardioid in the case of the Beyer, and cardioid in the STC.

So on with the restoration. My first job is to sort out that connector…….. I will report back.

SOME WHILE LATER……………………………………………………………………………..

The connector problem has been solved. Preh, the company who made the original connector still make exactly the same connector. So I have bought a brand new replacement!

Having prised off the grill it was immediately obvious that the ribbon was in need of replacement.  So I decided to take the whole thing to pieces and re-build it! As you can see in the pictures below the plastic horn is glued to the circuit board, which makes it a bit of a pig to get apart! After prising it all all round with the blade of a knife the glue eventually gave way without breaking the board. Phew!!

STC4113 Dismantled Pic 1STC4113 Dismantled Pic 2And now all I need to do is to make an new ribbon, line it up in that gap, get it nicely tensioned and do up the clamps without breaking it!!!!!

This may take some time …………………………………………..

Re-ribboning and rebuilding.

Da Dah!

STC4113 Fully RestoredFully restored and repainted !!                                                                                      OK now to find out what it sounds like……………….

CLICK HERE for  my first recording which is a simple voice test.

And now for something completely different………

 CLICK here for Ukulele and Flugelbone!

How to get that Vintage Mono Sound. A 1930’s Microphone Shoot-out!

In this age of manicured digital perfection, where nothing is quite what it seems,  I look back with nostalgia to a time when recording was all about capturing a performance by a great artist and not about manufacturing one!

At the present time when  so much R & D is being expended on surround sound, virtual reality and other forms of immersive audio, I find myself taking a renewed interest in Mono! Just as black and white photography still has it’s charms I think that there is a good deal to recommend about sound recorded in Mono.  Genuine Monophonic recordings made with just 1 microphone are completely phase coherent and coming from a single point there is something very focused and unambiguous about the sound. The listener’s attention is concentrated completely on the music and not distracted by artefacts of  multi-channel production. Recordings made in this way can also provide the listener with an excitingly honest account of a real performance. The balance is simply what felt right to the performers (or conductor) at the time and there is little scope for fiddling around with the mix afterwards. For the engineer the art of Monophonic recording is in carefully choosing the right microphone and positioning it in exactly the right place, ie the perfect listening position.

Echoes of France

Virtuoso gypsy jazz duo ‘Echoes of France’ (Fenner Curtis violin, and Andy Wood guitar) were looking for an authentic 1930’s/40’s sound for their latest recordings, harking back to the golden years of Django Reinhardt & Stephane Grappelli.  We had a very pleasant session experimenting with vintage microphones. In the space of a few hours recording in glorious Mono we laid down 12 complete tracks.  No overdubs, no mixing, no editing, no plugins, no special effects! However, what we did end up with is  3 different microphone recordings to choose from!

The  shoot-out is between the mighty Siemens SM3 ribbon mic, an STC4017 and an STC4021.  Although they are all from the 1930’s each of these microphones has a very distinctive tonal character.

Take a listen to this short clip of each of the three mics. CLICK HERE.

Please leave any comments below and vote for the winner.

1930 Microphone Shootout.

When I told my photographer that this picture was for a Microphone Shootout she suggested that perhaps they should be wearing cowboy hats for the occasion !!!

NEWS FLASH!

ECHOES OF FRANCE ALBUM OUT NOW!  

BUY HERE  

 http://www.echoesoffrance.com/  https://echoesoffrance.bandcamp.com/

Recorded on the mighty Siemens SM3 Ribbon Microphone.