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.


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


Frequency Response graph


Standard 3 pin small Tuchel  connector

MB UNITRA TONSIL MDO-23  Tuchel Connector


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


4 responses to “MB – UNITRA TONSIL MDO 23 (Circa 1975-80s)

  1. It’s a pleasure for me, Martin. You are the most useful mine of knowledge about microphones! I will just add that the purchase of a license from MB was considered controversial among Polish musicians. Unfortunately, not all licensed models were successful. The microphone you describe has just been positively reviewed. So why was so little of this model produced? Perhaps because it turned out to be less resistant to mechanical damage.

    Liked by 1 person

    • Ever since the 1960’s the market in dynamic microphones has been dominated by directional polar patterns (mostly cardioid). Omnis have never been made in the same quantities. In the case of the MDO 23 I suspect that very few were made. It seems to be well constructed and there is only a capsule and transformer inside it. So not much to go wrong.
      I would have thought that with such an unobtrusive neat design that they would have been popular with journalists for interviews and news gathering. Were they ever used by TV and radio broadcasters in Poland ?


  2. Terry Skelton

    Once again, the “click here to hear” function is not working for me. Sincerely, Terry Skelton Cell: 505-690-4617


    • I have contacted readers in several different countries and so far haven’t found anyone else unable to open the link. I’m mystified.
      I wonder if there is a problem with your browser and YouTube?


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