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Equipment file · Transverse-current carbon microphone

Marconi-Reisz microphone

Marconi · 1925–1927

Evidence status · documented

Identity and core specifications are documented; some historical fields remain unavailable.

The Marconi-Reisz microphone held carbon granules between electrodes in a hollowed marble block behind a thin diaphragm. It was the BBC's standard studio microphone from 1926 to 1933, replacing noisier Peel-Conner carbon microphones, and needed turning daily to keep its granules from settling.

Introduced
1925–1927
Category
Transverse-current carbon microphone
Intended use
Broadcast studio pickup
Production
Marconi, Chelmsford, from Eugen Reisz's German design

Equipment photographs · 1

Marconi Reisz microphone

1 / 1 · Marconi Reisz microphone

Marconi Reisz microphone·Jan Kameníček·CC BY-SA 4.0

Why it mattered

  1. 01

    A large fidelity gain over first-generation carbon microphones, with later versions within about 2 dB from 100 Hz to 8 kHz.

  2. 02

    It was succeeded at the BBC by ribbon microphones from the mid-1930s.

Engineering record

Construction
Carbon granules between electrodes in a marble block, fronted by a mica or rice-paper diaphragm[2]
Response
Within about 2 dB from 100 Hz to 8 kHz in later versions[2]

Original pricing

No reliable period price located

2026 equivalent

Not calculated without a reliable original price.

Public price evidence was not sufficient to publish a defensible original figure.

Use in the field

BBC standard studio microphone, 1926–1933[1]

Manuals & original documents

No authoritative manual or original document has been located for this profile.

Sources

  1. 1Marconi-Reisz 'Marble' MicrophoneScience Museum Group Collection · archive
  2. 2The Marconi-Reisz Carbon Microphoneorbem.co.uk · reference

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