Category Archives: 1980’s Microphone

MB – UNITRA TONSIL MDO 23 (Circa 1975-80s)

Between 1973 and ‘75 German microphone manufacturer MB Electronic (today known as MBHO) designed a range of quality microphones that were licensed to Polish state owned electronics company UNITRA TONSIL.

Back in May 2020 I wrote a post about the UNITRA Tonsil MCU-53, an excellent cardioid condenser. Now, (from the same stable) here is the MDO 23, a slender, omnidirectional, studio dynamic.

MB UNITRA TONSIL MDO 23

So What is it Good For ?

The thing I have always liked about omnidirectional dynamic microphones is the absence of proximity effect coupled with the ability to handle high SPLs. This makes them perfect for close-micing loud guitar amps without having to mess around EQing unwanted boominess caused by proximity effect. I have often used a Sennheiser MD21 on rock ’n’ roll theatre shows for this purpose.

Omni dynamics also make excellent speech mics and are very often used in TV and radio for interviews. Once again the absence of proximity effect is useful, allowing a good deal of freedom of movement without significantly affecting the frequency response.

Picking up sound from 360 degrees, Omnis are also just the job when it comes to capturing ‘atmosphere’.

CLICK HERE to hear a range of sound sources recorded with the MB UNITRA TONSIL MDO 23

Technical Specifications

MB UNITRA TONSIL MDO-23
MB UNITRA TONSIL MDO-23

Frequency Response graph

MB UNITRA TONSIL MDO-23  FREQUENCY RESPONSE GRAPH
MB UNITRA TONSIL MDO-23  Grill

Standard 3 pin small Tuchel  connector

MB UNITRA TONSIL MDO-23  Tuchel Connector

Conclusion

Having scoured the internet for information about this microphone I have come to the conclusion that it is somewhat rare! Apart from a couple of photographs, the tech spec and frequency response graph pictured above were pretty much all I could find. Sadly, it would appear that company records of this period have long since vanished in the mists of time.

In common with the MCU-53 I wrote about previously, this microphone has been generously sent to me by a friend in Poland, Adam Wilma. It is a serious quality professional microphone with a myriad of uses, and a very welcome addition to the Polish section of my collection. So thanks once again Adam!

Martin Mitchell Polish Microphone Collection

UNITRA Tonsil MCU-53

Acel GM-17B

MB UNITRA Tonsil MDO-23

Omnidirectional Dynamic Vocal Microphones

Up until the late 1960’s, cardioid, omnidirectional and figure of eight dynamic microphones were all commonly found in use on public address systems. Singers were able to choose whichever pattern suited their particular style of delivery. Figure of eight ribbon mics, for instance, were enormously popular with the jazz singers and ‘crooners’ of the 40’s and 50’s because of their smooth response and rich proximity effect which enhanced the low end of the voice. Omni was preferred by singers who required a more ‘open’ sound and the ability to move around without altering tone. Unfortunately, with the development of high power PA systems and the introduction of wedge monitoring in the late 60’s, only cardioid microphones had the required rejection characteristics to deliver a suitable amount of gain before feedback. Consequently, within a few years figure of eight and omni all but vanished from the stage and were pretty much banished to the studio!

I recently acquired a number of vintage omnidirectional dynamic mics from the tail end of the last century. Although the primary purpose of these mics was originally news gathering, my attention was drawn to the following excerpt from the AKG Engineering Data sheet for the D130. It perfectly describes the numerous benefits that an omnidirectional microphone offers the vocal performer.

AKG D130 Data Sheet.

A wide-range instrument, the D-130E offers “open”, natural reproduction of speech and music -without harshness, popping or bass emphasis. Moreover, the D-130E ‘s omnidirectional pattern and consequent absence of proximity effect enable the microphone to retain this natural quality -regardless of the relative position or distance of performers working into it. Together with its handling comfort and attractive styling, these same characteristics also lend the D-130E to a variety of hand-held on-camera applications in the studio -especially to pop-free coverage of vocalists who do not desire proximity effect.

Many singers (especially male vocalists) have an uncomfortable relationship with cardioid microphones because of their inclination towards ‘boomy’ bass and unpleasant popping plosives. I have also worked with performers who are in the habit of pulling away from the mic when delivering the loud bits leaving their voices sounding suddenly thin and weedy (N.B. Proximity effect works in both directions i.e. moving away reduces bass). With omni the bass remains constant with the desired reduction in volume.

And another thing………

For performers whose vocal style involves ‘cupping’ the back of a cardioid dynamic, maybe an omni would be a better choice? It comes ready ‘cupped’!

SM58 cuppingBeyer M58 2 N (C)

 

 

 

 

 

 

 

So…….. Here’s a thought…….

With the rise of in-ear monitoring many performers and bands are dispensing with their cumbersome (and feedback prone) on-stage wedges. So it would seem to me that for cardioid averse vocalists, perhaps now would be a good time to consider bringing back the considerable benefits of the

Omnidirectional Dynamic Vocal Microphone.

AKG D130

Electro-Voice DO56L Dynamic Shock Mount Omni circa 1980

Perfect for the socially distanced interview!Electro Voice DO56LElectro Voice DO56L OmniElectro Voice DO56L with original case

Following in the company’s long tradition the Electro-Voice DO56L is a triumph of innovative design and precision engineering. The 11 and a half inch 56L is the Long version of the DO56 and was intended as the perfect tool for TV news gathering or Talk Show Hosts. Even the dull ‘Silver tone beige’ finish was carefully chosen to be unobtrusive and none-reflective under TV lighting.

Electro-Voice advertising material from 1980 featured below explains in detail the design of this exceptional new microphone. The clever arrangement of the internal shock mounting is particularly impressive.

Electro Voice DO56L Literature. page1Electro Voice DO56L Literature. page2Electro Voice DO56L Literature. page 3

Phil Donahue Edit

Can’t beat a bit of subtle product placement/celebrity endorsement!

So What Does it Sound Like?  CLICK HERE for spoken word clip.

What else can it be used for?

Back in the 1950’s when AKG came up with the D12 they fondly imagined that they had designed a general purpose instrument and vocal mic. The marketing blurb featured photos of pretty girls warbling sweetly into the new microphone and indeed it was a great success with singers. Then along came the studio engineers who took a look at the tech spec and said, ‘Hey…. I bet with that frequency response curve and high SPL rating the D12 would sound great on bass drum’!  Within a few years it was on bass drums all over the world! In fact these days it is often referred to as the ‘legendary bass drum mic’ (no mention of vocals). So when I see marketing literature declaring a microphone to have a particular purpose I always find myself imagining (based on the tech spec) what else it might be good for.

Although the Electro-Voice DO56L was very much designed with demands of TV journalism in mind and a frequency response tailored to the human voice, I feel sure that it could also have a range of other uses. So let me see now……………

More Sound Clips to follow as soon as COVID-19 allows!

 

UNITRA Tonsil MCU-53 Cardioid Condenser (1970’s/80’s)

History

In the early 1970’s MB Electronic (now known as MBHO) produced the MB C540. This was a high quality battery powered condenser microphone. It boasted an almost flat frequency response from 20Hz to 20kHz with a slight dip at the low end. The MB C540 was modular in construction and had the option of 2 capsules (omni or cardioid).

MB C 540 AdvertMB C 540 Frequency response

In the UK it appeared as the PEERLESS MBC-540.

Reviewed here in Studio Sound May 1977.Review. Peerless MBC 540 - Studio Sound - May 1977

Meanwhile in Communist Era Eastern Europe.

This German design was also manufactured under licence by the Polish state owned electronics company UNITRA Tonsil and marketed as the MCO-30 (omni) and the MCU-31 (cardioid). According to Polish sources, the only difference between the German and Polish versions appears to have been variation in quality control at the Tonsil factory. This lead to some Polish mics reputedly sounding rather better than others.

Around 1980 the design was modified and updated. Whether this was done by MB Electronic or by Tonsil’s own engineers is not clear. (MB licenced a number of different designs to Tonsil but sadly MBHO now have no records relating to this microphone !)…….. Anyhow, the resulting microphone was somewhat shorter in length, the battery powering was changed from 2 x 15v to 1 x 6v and the previously unbalanced output was upgraded to balanced. The WCU-31 and WCO-30 capsules were retained and the frequency response appears pretty much the same. The new model was the UNITRA Tonsil MCU-53 (cardioid) / MCO-52 (omni).  The Tonsil 50 series continued in production through the 1980’s. In the late 80’s a further modification was carried out to provide 48v phantom power. This model was the MC-265.

UNITRA Tonsil MCU-53

UNITRA Tonsil MCU-53UNITRA Tonsil MCU-53 exploded view

A clever modular design. Well constructed and finished in shining nickel plate.

Tonsil WCU-31 Cardioid capsule. Front view

WCU-31 Cardioid capsule.

WCU-31 Cardioid capsule. Rear view.

Unusual 5 pin DIN connection.  (below)

Pins 4&5 in the plug are shorted together to provide a ‘switch’ for the battery. When the cable is plugged in the power is thereby switched on. N.B. This also means that if you accidently leave it connected when not in use you end up with a flat battery!! Arrrgh!

5 Pin DIN socket on Tonsil MCU-53 5 Pin DIN plug Tonsil MCU-53 Tonsil MCU-53 5 pin DIN Plug

Technical Specifications.

Pages from MCO-52/ MCU 53 Owner’s Manual UNITRA Tonsil MCU-53 ManualUNITRA Tonsil MCU-53 Manual P2UNITRA Tonsil MCU-53 Manual P3

In Conclusion.

Being battery powered made the MCU-52 /53 suitable for use with cameras and tape machines which in the 70’s and 80’s often did not provide phantom power. This made it a popular choice for wildlife and location recording.

When there is once again an opportunity to record music I will be interested to see how the MCU-53 compares to the AKG C451E as their frequency responses appear to be somewhat similar. I suspect the Tonsil may have a bit more self-noise but tonally may give the AKG a run for its money. Let’s wait and see…………

Credits.

Many thanks to Adam Wilma for sending me this pristine example of the UNITRA Tonsil MCU-53. Very generous. And thanks to my old mate blues guitarist Keith Thompson for bringing it back from Poland. His March tour was sadly cancelled after only 2 shows as Poland went into COVID-19 lockdown. Luckily for me the second gig was in Adam’s home town of Torun and he kindly dropped the mic off for Keith to bring back before the borders closed!

Update Dec 2021

CLICK HERE to hear the MCU-53 on Acoustic Guitar.

AKG C451E (Circa 1970) A Classic from The Golden Age of AKG

Today AKG is little more than a brand name owned by a multi-national corporation. Like a tired old rock star it rests on the laurels of its former glory whilst still churning out a few old favourites.

However, if we go back to the late 1960’s and into the 70’s AKG was a powerhouse of innovative design and high-tech engineering. Major achievements include the D200 series which took dynamic microphone design to a peak which even today sees few competitors. This period also saw the legendary C12 condenser evolve into the C414 which continues to be a favourite in studios across the world.

In 1969 AKG launched its newly developed Condenser Microphone System (CMS) using audio frequency circuitry with Field Effect Transistors. This was a fully modular microphone system based around the C451E, the inherent features of which were claimed to be;

  • Low noise level,
  • Extremely high reliability and
  • Life-long sta­bility.                                                                                                    

AKG C451E with old style logo

AKG C451E no serial number

A selection of interchangeable capsules and extension tubes could be purchased along with a variety of accessories covering a wide range of recording and live sound applications. The CMS proved to be enormously popular with broadcasters, TV companies and studios throughout the 1970’s and beyond, and can be seen on many BBC music programmes of the period.

These contemporary AKG brochures/guides explain the features of the CMS in detail.

AKG C451 CMS Technical Specifications

Technical Info AKG CMS microphones.

AKG CK1 CapsuleAKG C451E with capsule removed.AKG C451E body with CK1 Capsule

C451E original case interior AKG C451E Original case

My C451E

Judging from the old style of logo and the lack of an externally stamped serial number on my newly purchased C451E (see top 2 pics), I think that it must be a fairly early example. It is in perfect condition and even the case is hardly marked. As always it was a bargain!

So What Does it Sound Like?    

Sadly, like many, many other people I am stuck at home at the moment practicing social distancing, and so recording music with my beautiful new C451E will have to wait until the current COVID-19 pandemic dies down and we can all get back to work!

Meanwhile Stay safe!

P.S.   Went for a walk today and recorded this:-    https://www.youtube.com/watch?v=k5MHEL6ZPHI

 

Acel GM-17B. A ‘Mystery’ Polish Microphone (Circa 1987)

This wonderfully shiny and somewhat obscure vintage microphone was kindly sent to me as a Christmas gift by Adam Wilma, one of my Polish readers!

It is interesting, not because of its fabulous quality, but because it provides a small window into a fairly grim chapter of Polish history.

Acel GM-17B Cardioid Dynamic Microphone

GM-17B Cardioid Dynamic Stage Microphone

GM-17B Box

After 30 years of Communist misrule, the Polish economy was in an extremely precarious state with serious shortages of many goods. Shops were empty with long queues in the streets. In March 1979 the Ministry of Internal Trade listed 280 products for which demand was difficult to satisfy and the list grew longer in the following year. 1980 saw the formation of the free trade union Solidarity and the end of Communism seemed to be in sight. However, in 1981 General Jaruzelski declared martial law and Solidarity was banned. The USA imposed sanctions and for the next 10 years the Polish economy struggled along in a state of collapse. This lead to the rapid growth of a black or ‘grey’ market. In these conditions a ‘second’ or ‘parallel’ private sector economy flourished.

Acel GM-!7B Dynamic MicrophoneSmall scale private businesses were broadly tolerated and allowed to function supplying demands that could not be met by the ‘official’ economy. However, if a company became too large and successful it risked attracting unwelcome attention from the Communist bureaucracy and might be shut down and its assets seized. This probably explains why the Acel GM-17B microphone pictured in this post, with its original packaging, gives away little clue about the company who made it or their whereabouts! So far all attempts to trace the manufacturer have failed! Goods like this were sold through local craft associations/co-operatives, which was a way of avoiding the many permits and licences that were officially required. All we know is that this particular microphone was sold in 1987 by the Multi-Branch Co-operative in Leszno. The previous owner informed me that it cost 15,330 old zloty. (For comparison, in the same year a kilo of carrots cost 50 zloty, and a kilo of tomatoes 200 zloty).

1980’s Polish Music Scene

For musicians this was a difficult time and few could afford good quality equipment imported from abroad. The electrical industry had been particularly affected by shortages of raw materials, components and machinery. Local manufacturers did their best to meet demand with limited resources. Sadly the resulting equipment was often somewhat less than ideal! Paradoxically, this decade saw a flowering of rock music in Poland. In no other communist country was there such freedom for musicians. It was not by accident – the communist authorities calculated that for young people it would be a good way to neutralize frustration. Freedom for various subcultures also served to draw young people away from the Catholic Church, which was perceived to be their greatest threat. It was not by chance that the dates of the biggest music festivals coincided with important dates in the Catholic calendar.

Polish Plug Problems!  

One Acel GM-17B Connector.slightly annoying feature of Polish-made gear of this period is the non-standard connector! Although this may look like a standard Klein Tuchel socket (as found on German and Austrian mics of the 60’s and 70’s), the locking ring is slightly larger with a different thread. I am told that Polish-made guitars often came with non-standard jack sockets. Slightly bigger or smaller! Presumably this meant that you would have to purchase a special lead from the maker at extra cost. Or maybe it was to avoid patent infringement? Who knows?………….Anyway, an ordinary Tuchel plug on the GM-17B can be kept in place with a piece of gaffer tape!

So What Does it Sound Like?  

During the Communist era, here in Western Europe we were always lead to believe that products made in the USSR and Eastern Europe were bound to be inferior to anything made in the West! Indeed, even now I am assured by a musical connection in Poland that Polish-made gear of this period was very poor and that this microphone can probably be summed up by one word: ‘CRAP’!!  Anyhow, I don’t like to jump to conclusions so I thought I would give it a fair trial……………..

CLICK HERE TO HEAR THE GM-17B in action…….. and reach your own verdict!

Many thanks to Keith Thompson for the tasty guitars and vocals (I played shaker and programmed the kick!) and thanks once again to Adam Wilma for sending this interesting and unusual microphone.

 

AKG C747 More Than Just A Podium Conference Mic.

AKG C747

First introduced in 1987 the AKG C747 was originally designed for ‘unobtrusive speech applications when mounted on a podium or lectern, or for teleconferencing activities’.  From this somewhat uninspiring start, these days the C747 is widely acknowledged as one of the most versatile microphones AKG ever produced!

Just a glance at the tech spec tells you that this was not a microphone simply doomed to deliver the Chairman’s annual report!

  • Smooth frequency response from 30Hz -18kHz.
  • Rapid transient response produced by tiny, low-mass, capsule.
  • Tight hypercardioid polar pattern, giving excellent separation.
  • SPL rating of 133db.
  • AKG C747 Frequency Response GraphAKG C747 Polar Pattern

It didn’t take engineers long to realise that this neat, pencil sized miniature shotgun microphone has many uses away from the conference hall!

AKG C747 Matched Pair

I recently acquired a well-matched pair of old C747s and it occurred to me that although advertised as having some ‘shotgun’ characteristics, these neat little condensers do in fact behave pretty much the same as any other hypercardioid microphone.  I therefore wondered how they would get on as a crossed stereo pair.  I have seen them occasionally used like that in a conference speech setup, but never recording a large symphony orchestra! (Frequently used as spot mics but certainly not as the main pair!)  So here goes …………

CLICK HERE for Symphony Orchestra sound clip.

The mics were crossed at 65 degrees (at the capsules) and positioned on a tall stand about a metre behind the conductor. N.B. To get the full effect of this recording you need to download it in full resolution and play it on speakers at the sort of volume that will really annoy your neighbours!

AKG C747 Crossed pair at 65 degrees

Here below are the Tech specs for both the AKG C747 and the current model the C747 11.  It is interesting to note that in the C747 11 literature various instrumental applications are also illustrated. (guitar, saxophone, snare, drum) The newer model also has a slightly different frequency response, more tailored towards speech. Either way these are fabulous, unobtrusive, little mics that will blend seamlessly into almost any situation!

C747-manual

AKG_C747_Service_Documentation

AKG_C747V11_Manual

AKG_C747V11_Polar_Patterns

AKG_C747V11_Cutsheet

N.B.  The Hi-Pass filter on these mics is hidden away in the XLR plug (also containing the mic preamp) I included this last photo because, in conversation with the previous owner, he told me that he never realised that the 747 had a hi-pass switch!! When working close up he ‘Always found them a bit too bassy ‘ !

AKG C747 Hi-pass filter