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B&O Carbon Microphone; B&O's first mic, from 1936



B&O 'Beolit': "the Danish microphone is now a fact"

This first Danish made microphone was a carbon type, like the better known Reisz microphones which were the earliest professional models used for (European) Radio, since the early Twenties.

It's simple but refined Art - Deco shape is an early example of the stylish designs that would make Danish B&O audio products famous around the World.

The material used for the casing is pressed 'Beolit', a Bakelite like product, B&O claimed that this provided significantly better protection for the carbon granules, compared to the marble casings Reisz used. The specially selected coal grains and the proces they went through were said to reduce the noise to a minimum.

The membrane was made of cellophane and it was fitted with a rubber band that allowed it to be used with any ring mounted stand.

The microphone was powered by a 4,5 volt battery and could be connected directly to a radio transmitter, or used with a special transformer it could be hooked up to a record player.

Bang & Olufsen was founded in 1925, by two friends who decided to make radio products. It had taken quite some time before their "Kulskorner' (carbon powder) design was ready for serial production, since the company wanted to be sure that all microphones that were produced would equal their high standard of quality. Even though the operating principle of a carbon microphone is simple, production of a uniform sounding product is difficult. In 1936, it was presented and the Danish press sang its praise and deemed the price reasonable, compared to foreign products.

Around 1936 many countries preferred national products over foreign ones; the sort of pride that led to some of the darkest pages in history.

B & O would later name many of its products 'Beolit', even though not all of those were made of that material.

Last year, I finally found one of these first B&O microphones; it is one of the rarest in my collection, and even information about it is very scarce. Therefore I have included an undated B&O ad and a Danish radio magazine article about it, from May 1936.

In my book there is only a picture of this model, with Danish singer Ingelise Runde, probably from an old B&O ad (see picture).

Many more microphones feature in my book Witnesses of Words, which was recently released. More information about that can be found at

wow cover


B&O carbon microphone

B&O carbon mic back
B&O ad 1936

Top: the stylish B&O

Underneath: 1936 ad for the Danish B&O : "the Danish microphone is now a fact"

Next: review in Danish radio magazine from 1936

Below: sound and ad with Danish singer Ingelise Runde

B&O Radiomagasin 1936

B&) Ingelise Runde