Alan Blumlein, Audio, Video, and your Lazy Boy Chair?

Our consumer electronics industry stands on the shoulders of those who came long before us.
Shoulders that include but are not limited to Edison, Bell, Tesla, Marconi, Farnsworth, and Alan Blumlein.

Wait, Alan Who?

Alan Blumlein was an electronics engineer and war hero who perished at age 38 in a 1942 airborne radar test flight. Blumlein’s radar work alone places him in a unique category of historic inventors.
He was a lead member working on airborne radar against ground-level targets like German U-boats.
This work was critical in the defeat of Nazi Germany.

In Blumlein’s short life, he became, with a total of 128 patents, one of the most prolific inventors of the twentieth century. His instrumental work influenced the development of early television, stereo audio, and cinema sound, which laid a path for today’s commercial and consumer audio/video products and my career.

Television

From 1933, Blumlein worked on early television technology that emerged as the 405-line Marconi-EMI system television service. Like many engineers and scientists of the day, this work was interrupted by the Second World War. The British government secretly recruited the EMI team to assist the war effort using their sonic know-how to create radar systems.

Stereo Audio

Alan Blumlein is remembered most for positioning a pair of microphones, processing the audio, and the equipment to record two channels into a single record groove. In 1931, he called it “binaural sound”.
We call it stereo audio.

Blumlein’s audio work covered additional developments still used today, such as paired microphones with axes at right angles to each other, known as a “Blumlien Pair.” He created matrix circuits that preserved directional audio effects from a spaced pair of microphones and reproduced them via stereo loudspeakers.

In 1924, he measured the amplitude & frequency response of human ears and used the results to design the first weighting networks. This work led to his IEE’s Premium Award for innovation. Audio enthusiasts may recognize this weighting as a precursor of the Fletcher Munson loudness curve.

Cinema Sound

This fact caught me by surprise.
Stereo audio is about music — right?
Well, “binaural sound” was born in a movie theater.
The inventor of our treasured music-only stereo audio systems was motivated by movie sound.

Blulmlein was distracted and dissatisfied with the monophonic cinema theater sound of the era.
Sound systems of early “talkies” only had a single set of speakers – the actor might be on one side of the screen, but the voice could come from the other.

He invented “binaural sound” stereo audio technology to make the sound follow the actor.
He also engaged his matrix circuits to create directional effects via left-right, sum, and difference signals.
This matrix concept ultimately led to 1970s Dolby surround sound.

Cheerio

The development of radar, early television, and stereo audio are groundbreaking accomplishments.
Alan Blumlein belongs to a pioneering list that includes Edison, Bell, Tesla, Marconi, & Farnsworth.
Give him a “thumbs up” when you sit in your Lazy Boy comfy chair to enjoy your stereo audio or home theater surround sound system.

Select from the following links for more information.
The Fascinating Story of Alan Blumlien
Alan Dower Blumlein 29 June 1903 – 7 June 1942
Historic Recordings
More audio info @ Ed’s AV Handbook

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