Discovernet: Speaking machines

from the collection of the Powerhouse Museum, Sydney

Imagine living in a world where the only opportunity you had to listen to music was when musicians were playing in a public space or in your home. Strange as it may seem, that’s how it was not so long ago.

Think of how different it is now. There are many ways and places where you can hear recorded music and other sounds - on television and videos, at the movies, on radio, MP3s, CDs, LPs and DVDs. Can you think of any others?

It was only just over a hundred years ago that people began to experiment with ways of recording sound. They knew that sound travels through the air like waves in the ocean, so they built machines which could capture these sound waves using funnels called megaphones or horns. The waves travelled through the funnel to a diaphragm. Just as your eardrums vibrate when you hear a sound, the diaphragm vibrated and this movement was then passed to a small needle, which made marks in wax or tin foil. These marks were a record of the sound waves, which these early sound recording machines could then play back.

People continued researching and developing new designs and the machines they built were more sensitive to sounds they recorded and played back. Other inventions were also helpful; in particular the microphone, which is used inside telephones and the valve, which was used in radios. In 1915, a magnetic wire-recording machine called the telegraphone used a microphone to capture sound waves. It then changed the waves into electrical signals and a small but powerful magnetic field transferred the signals to a reel of wire, where they were stored. The telegraphone was part of an important change that was taking place - from acoustic to electronic recording and reproduction of sound.

The invention of the transistor in the 1950s was very important - it meant that electronic sound devices could be much smaller and more portable. Music could now be heard in your car, at the shopping mall, in lifts and at the beach. Many new styles of music were developed. People experimented with sounds, adding effects to music like echoes and ‘looping’ recorded sounds. They even created electrified musical instruments! Long Playing (LP) records, 45s, jukeboxes, the transistor radio and DJs changed the way people listened to music and it also changed the music they listened to.

The most significant change to sound devices over the last fifty years - the change from analogue to digital sound, has been brought about by the introduction of computer technology. The power of digital computers was applied to music instruments, radio production, recording devices and broadcasting. Having sound in digital form has allowed people to experiment again in different ways. New styles of music and new uses for sounds continue to be developed because of this latest change in technology. You can now hear digital sound in all sorts of places - in films, at the train station, in computer games, mobile phones, cameras and many other machines.

Understanding and studying the impact of technological changes in sound devices over the last 150 years is not just a matter of noting improvements. Each change in the development of sound-recording devices has been closely related to how people perceive, use and make sound in our world. The technology is still developing - where could it go next?

Campbell Bickerstaff, Assistant Curator, Information Technology, Powerhouse Museum.