Overview
Gerhard M. Sessler (born 1931) co-invented the electret condenser microphone with James West at Bell Labs in the early 1960s, and later contributed to the development of the silicon MEMS microphone. Between them those two devices account for essentially every microphone in consumer electronics.
What You Need
- Born 1931, Germany, worked in the United States and Germany
- Anchor year: 1962 — the electret condenser microphone
- Strand: overlooked
Steps
The problem as it stood
Same as for West: condenser microphones were excellent and required a polarising supply, which ruled them out of anything small, cheap or battery-powered.
What he actually did
Sessler and West developed the electret transducer together, and Sessler continued working on electroacoustic transducers for decades afterwards at the Technical University of Darmstadt, including on silicon micromachined microphones.
How it worked
The electret supplies its own bias. The MEMS successor takes the same principle into semiconductor fabrication: the diaphragm and backplate are etched from silicon, so the microphone becomes a chip that can be placed by the same machines that place every other component.
What it made possible
The electret put microphones into telephones and consumer audio; MEMS put several into every smartphone, enabling beamforming, noise cancellation and always-listening voice assistants. The second step is what made microphone arrays economically ordinary.
What happened to him
He returned to Germany as a professor at Darmstadt, publishing extensively on electroacoustics, and has received major awards jointly with West.
Where the credit landed
Sessler has a separate page from West because the contributions are separable — he continued into the MEMS generation that West did not, and that second step is what made microphone arrays ubiquitous. Splitting genuinely joint inventors into one page each is the corpus's rule only where their work diverges afterwards; where it does not, the pair share a page.
Pro Tips
- The electret and MEMS generations between them cover nearly all consumer microphones.
- MEMS turned the microphone into a placeable chip, which is why phones have several.
- Microphone arrays and beamforming are downstream of MEMS economics.
Knowledge Base
What You'll Learn
Two transducer generations, one operating principle, sixty years apart.
Why several microphones are better than one
With two or more microphones a fixed distance apart, sound from different directions arrives at slightly different times. Combining the signals with matched delays reinforces one direction and cancels others — beamforming, in software, with no moving parts. That is how a phone isolates your voice from a noisy street, and it only became practical once a microphone cost pennies and occupied a few cubic millimetres.
Where This Fits
This guide covers one specific part of the history of media technology. The wider picture — how each link in the chain from capture through transmission to display was actually built, who built it, and why the credit so often landed somewhere else — is in A History of Broadcast Technology: The Chain From Capture to Screen, which frames the discipline as a whole and links out to the detailed guides underneath it, including this one. If you are starting from scratch rather than solving a specific problem, read that first and come back here.
FAQ
Q: What is a MEMS microphone?
A: A microphone whose diaphragm and backplate are micromachined from silicon, making it a surface-mount component. It works on the same capacitive principle as the electret but is manufactured like a chip.
Q: Why do phones have more than one microphone?
A: To beamform — combining several signals with matched delays isolates sound from a chosen direction and cancels the rest, which is how voice is separated from background noise.