Audio Engineering Facts – Did You Know?

It is easy to get lost in the fun of recording or mixing music with the equipment that we have today. Most of the time, it never really occurred to us that the technology we are currently enjoying, wasn’t always available to people in the past. Thanks to the engineers and scientists working tirelessly in the field of research and development, recording music in the comfort of our own bedroom has become a norm.

In today’s article, I would like to take a trip down memory lane and trace back some of the oldest, or rather, most primitive versions of the audio equipment that we all use to produce music at home (or anywhere for that matter). Here I present to you, 5 audio engineering facts (pertaining to equipment) that you probably have never heard of, or even if you have, please just read it anyway =)

1. Earliest “microphone” was a mask

Imagine performing in a venue in front of a rather large audience, without any way of amplifying your voice. Wouldn’t be too much fun I suspect? Hence, scientists in the past invented a device designed to increase the volume of the spoken word.

Roman Mask

Photo by Walters Art Museum / CC BY-SA 3.0

The earliest known device that has that function in it’s core design, dates all the way back to 600BC, with the invention of masks that have uniquely sculpted mouth pieces that serves the purpose of acoustically augmenting the voice in amphitheatres. Then in 1665, the English physicist Robert Hooke, experimented with a medium other than air, and came up with a device known as “lover’s telephone”, which is made of stretched wire and a cup attached at each end.

A German inventor named Johann Philipp Reis, also designed an early sound transmitter that used a metallic strip attached to a vibrating membrane that would produce intermittent current. The technology was further improved upon with the “liquid transmitter” design in Scottish-American Alexander Graham Bell’s telephone of 1876, where he had the diaphragm attached to a conductive rod in an acid solution. However, these systems did not give satisfactory results.

2. The First Loudspeaker was in a Telephone

The earliest known practical use of a loudspeaker was in a telephone. In 1861, Johann Philipp Reis installed an electric loudspeaker in his telephone, and it was capable of reproducing clear tones, but also could reproduce muffled speech after a some modifications were made to the older version.

Phillip Reis Telephone

Johann Phillip Reis Telephone

Alexander Graham Bell also invented his first loudspeaker (as part of his telephone), and had it patented in 1876. His version was able to actually reproduce intelligible speech. This loudspeaker was then followed in 1877 by an improved version from Ernst Siemens.

Horace Short then patented a design for a loudspeaker driven by compressed air in 1898 and later sold the rights to Charles Parsons, who had several additional British patents already issue to him before 1910. Some companies, including the Victor Talking Machine Company and Pathé, produced record players using compressed-air technology. However, the drawbacks of these designs were their poor sound quality and inability to reproduce sound at low volumes.

3. First Recording Device was not Electronic

Berliner Gramophone

Berliner Gramophone 1899 / Photo by Phonogalerie.com / CC BY-SA 2.0

Towards the end of the nineteenth century, Edison and Berliner first developed recording machines with little or no electrical apparatus at all. The recording and reproduction process itself was completely mechanical.

This particular system they had invented, utilized a small horn terminated in a stretched, flexible diaphragm attached to a stylus which then cuts a groove of varying depth into the malleable tin foil (On Edison’s “phonograph” cylinder) or of varying lateral deviation in the wax (On Berliner’s gramophone disc).

Electronic recording only started to gain popularity during the 1920s. The principle that was driving it was known as “electromagnetic transduction”. Being able to remotely connect a microphone to a recording machine meant that microphones could be positioned in more suitable places, connected by wires to a complementary transducer at the other end of the wire, which drove the stylus to cut the disc. What’s convenient is the fact that the electrical audio signals coming from the microphones could be mixed together before being fed to the disc cutter, allowing greater flexibility in the balance.

4. Headphones – The only way to listen to sound

Brandes Headphones

Brandes Headphones

Originating from the earpiece, the headphones were the only way to listen to electrical audio signals before the development of amplifiers. In 1910, Nathaniel Baldwin successfully developed the first set of headphones, which were made by hand in his very own kitchen and then later sold to the United States Navy.

Around 1919, Brandes manufactured very sensitive headphones, which were commonly used for early radio work. These specific type of headphones utilized moving iron drivers, with either single ended or balanced armatures. As being “high in sensitivity” was a requirement in its design, no damping was used in the creation of the headphones, thus the sound quality was crude. Sufficient padding were also lacking in the early designs, which often results in discomfort due to excessive clamping forces on the wearer’s head.

5. XLR Connector used to be known as “Cannon Plug”

James H. Cannon, founder of Cannon Electric in Los Angeles, California (now part of ITT Corporation), was the person behind the invention of the “XLR” connector. Ultimately, this was the reason why the “XLR” connector was sometimes colloquially known as a Cannon plug or Cannon connector and in Japan as Cannon jack, though you don’t hear this term being used in the audio industry any more.

XLR Connectors

XLR Connectors / Photo by Michael Piotrowski / CC BY-SA 3.0

Originally manufactured as the Cannon X series, a locking mechanism was then added in 1950 (Cannon XL) and by 1955, a new version (surrounding the female contacts with a synthetic rubber polychloroprene insulation) was created using the part number prefix “XLR”.

There was also an “XLP” series, which used a hard plastic insulation, but was otherwise the same. ITT Cannon originally manufactured XLR connectors in two locations Kanagawa, Japan and Melbourne, Australia. The Australian operation was sold to Alcatel Components in 1992 and then acquired by Amphenol in 1998. ITT Cannon continues to manufacture XLR connectors in Japan.

There you have it, 5 facts of the audio engineering world that you probably did not know (You didn’t, right?). Anyways, thanks for dropping by and do leave comments below!



When I'm not rocking out to great music, I'd prefer to be sleeping on a field on a windy day =)


  1. This article proves that I know nothing about audio engineering. That’s so crazy that the earliest microphone was a mask and from as far back as 600BC. Thanks to you after reading this post I now know 5 new things I didn’t know before and probably never would have known if i didn’t read this. so thank you

    • It’s a pleasure to be able to bring you this information. Thanks for dropping by!

  2. haha great post my friend it was light hearted yet factual both at the same time. It does not take long at all to workout that you have put a lot of research into this article. It is OBVIOUS. Great and i didn’t know about the headphones stuff!!! Thanks for all of the good information you will do well, I’m certain of it matey.

    • Hello Simon, thank you for your kind words. Yes, it did take a little bit of digging to get the information and I am glad you liked it!

Leave a Reply

Your email address will not be published. Required fields are marked *