Most humans on the planet take sound for granted. We use it directly to communicate, we use it for relaxation and entertainment, and it forms the incidental backdrop to wherever we go and whatever we do.
But by taking it for granted, few people ever consider what sound is, and how it works.
Despite this, for almost 200 years, humans have become extraordinarily good at capturing sound and, once captured, playing it back at will. So, how did we make sound physical? First of all, it will help to understand what sound actually is. In essence, sound is vibration, so it needs something to vibrate in order to travel from its source to, for example, your ear.
Sound can pass through a solid, such as the rumble of traffic heard through a brick wall, or through a liquid, such as whale song carrying across countless miles of water. But most sounds that we experience travel through the air, which is a gas. We often think of the air as being ‘not there’. We can’t see it, after all, and only when the wind blows do we feel the sensation of the air moving.
But the air around us is actually a dense soup of particles, and sound travels through it from its source as a vibrating wave. This is why we refer to sound as sound waves and having wavelengths. It’s also the reason no one in space can hear you scream – space is a vacuum, lacking a gas to vibrate and carry sound. The other aspect of sound to consider is our perception of it.
We cannot hear all sounds, just those on the range known as audio frequency. Sounds above the frequency are called ultrasound and sounds below it are known as infrasound. By the mid-1800s, the desire to somehow capture sound was intensifying. The Industrial Revolution was in full swing and our understanding of the world and how it works had never been greater.
We were already taking the first photos, allowing us to keep a moment in time. Surely harnessing sound would be a logical next step. The earliest known successful attempt to record sound came in 1857, when a French bookseller, Édouard- Léon Scott de Martinville, built his phonautograph. Looking like something from a Victorian kitchen, this cumbersome device used a boar’s bristle attached to a membrane to etch sound vibrations onto a glass plate coated with lampblack (a carbon byproduct of combustion or, as some might call it, soot).
The idea wasn’t to play the sound back, but to capture it, so sound could be seen and its shape studied. Because Scott de Martinville’s invention wasn’t intended for playback, his contribution to audio history had been long overlooked – until relatively recently. In 2008, the First Sounds Project successfully scanned a recording he’d made of ‘Au Clair de la Lune’ (‘By the Light of the Moon’). By digitally manipulating the recording it was possible to make out the voice of the singer, although, should you listen to it yourself, you’ll be excused if you hear something ethereal and haunting rather than a melodious tune.
Even so, a device that wasn’t intended for playback has allowed us to hear a voice from 1860. It’s the earliest known recording of sound. When Thomas Edison built his phonograph in 1877, he was building on Scott de Martinville’s work. Edison’s machine kicked off what is known as the Acoustic Era, where conical horns gathered and focused the sound waves on to a diaphragm connected to a stylus.
The stylus, moved by the vibrating diaphragm, etched the movement onto a medium such as a wax cylinder, coated paper, or disc. Although a step-up from Scott de Martinville’s phonautograph, the phonographs were still crude creations, unable to capture a broad segment of the audio spectrum. 27MAKING SOUND PHYSICAL Performers had to be carefully arranged around the soundcapturing horn to ensure a balanced sound was caught, and subtler instruments had to give way to louder ones.
Even so, the excitement generated by these early recordings was infectious, and a lot was learned over the 50 years following Edison’s debut. By today's standards it was clumsy, underscoring just how far there was to go before we’d reach the heights of, say, Dolby Atmos. The winner of this early recording medium was the disc, proving to be the most popular and endurable method of capturing and replaying sound. When the new Electrical Era arrived in 1925, with its electronic microphones and amplifiers, the process of cutting a disc remained little different to the Acoustic Era.
At the point of recording, a master was made first before being transferred into metal. This was then used as a template to stamp a resin record – originally shellac, but the industry would eventually settle on polyvinyl. The electronic revolution of sound was made possible by Western Electric, an American company that was able to persuade the major US music labels to adopt their new technology. With a wider frequency now being captured, sound quality improved, allowing for a warmer, deeper sound with more subtlety.
But the manipulation of this sound required skill and understanding, so the first audio engineers came on the scene to harness and cajole the sound in the best possible way. All these innovations had wider implications, too. Home record players improved dramatically and broadcast radio was born. In Hollywood, the race was on to provide sound with movies, although some progress had already been made here.
The first film with sound was 1927’s ‘The Jazz Singer’ but this used a soundtrack record that had to be played on a turntable linked up to the projector. Within a handful of years studios were recording sound directly onto the roll of film itself, using a narrow strip to the side of the image. This was achieved by using sound to manipulate a light source. The projector would then use a photoelectric cell to convert the recorded sound to an electrical signal that could be blasted through loudspeakers to the audience.
Incidentally, loudspeakers – or, to give them their proper title, electro-acoustic transducers – have barely changed at all in the last 100 years. Their accuracy and reliability means little improvement has been required. By 1945, audio recording changed again. Germany had been using magnetic tape since the 1930s, but due to the war it hadn’t spread beyond Germany’s border.
During the war, the Allied forces had become aware of how German pre-recorded radio broadcasts sounded as good as their live equivalents, but the nature of how this was done remained a mystery. With the war over, it quickly became the default way to record, paving the way for high fidelity stereo recordings to enjoy at home. In the studio, multi-track recording became the norm, with pioneers such as The Beatles (and George Martin) experimenting with its endless possibilities.
Discs were no longer what artists recorded their music on to – this was now the Magnetic Era, so albums went on to master tapes. These advancements, in turn, powered other changes as the quality improved, albums got longer, and the consumer’s appetite for new music expanded. In the world on vinyl, 33 rpm was invented for the long-playing disc (LP) and 45 rpm disc for the single. Tape recorders flourished as an easy way for anyone to record and playback sound, their portability a huge bonus even when their battery life wasn’t so great.
Sound was also being captured for manipulation by keyboards, allowing for the creation of whole new sounds. This would open the door to the next era of audio. The Digital Era, in which we remain in now, has been a period of phenomenal change and innovation. It started in 1975, and by the millennium the new practices and technology had obliterated all studio practices that came before it.
At the era’s outset, the LP and the 7-inch single were soon put under pressure by the emergence of new formats. loudspeakers – or, to give them their proper title, electroacoustic transducers – have barely changed at all in the last 100 years DAT (Digital Audio Tape) combined the hero of the Magnetic Era with the new tech by recording digital sound on to magnetic tape.
But it was the creation of the CD, by Sony and Philips, that really changed how we listened to music. With no stylus to drag along a groove, or head to pass the tape through, CDs avoided anything physical touching the disc as they used a laser to read what was encoded there. In theory, they could last forever, if looked after. Music lovers turned to the CD en masse, in some cases buying much loved albums all over again as they replaced their vinyl.
By the end of the 90s the CD dominated and it looked like it was here to stay. Then along came digital audio files. Largely championed by Apple’s hardware and software, the iTunes store and the iPod changed the musical landscape again. Clever compression techniques had made music files small enough to make home use not just possible, but appealing.
No vinyl to scratch or jump, no magnetic tape to unspool, and no dust or greasy fingerprints to upset your compact disc player. Knowing you could carry a thousand songs in your pocket was a powerful sales incentive. What followed was another dramatic shift in listening habits, and more record collections being replaced. Master tapes became a thing of the past as well.
Now everything was on a hard disc, and that hard disc might not even be in the same room as you – or city, or even country. The finer aspects of digital allowed for even more remarkable feats to be achieved with audio, a perfect example being the recent, and supposedly final, Beatles recording ‘Now And Then’. The song was originally written by John Lennon in 1977, long after The Beatles had split. It was never more than a home-recorded demo, using a tape recorder.
The song was never completed or recorded. In 1994, years after Lennon’s murder, Yoko Ono gave Paul McCartney two cassette tapes containing Lennon’s demos. The three remaining Beatles got to work on the song the following year, creating a backing track to overdub Lennon’s recording. Although they made progress, there was a serious problem in the way the piano Lennon was playing was drowning out his voice.
Common with many tape recordings, the electrical hum from the power supply could also be detected. George Harrison found it particularly frustrating, so, despite what they had achieved, the song was abandoned after a single afternoon. By 2021, long after Harrison himself had died, director Peter Jackson and his team were working on even older Beatles material, pouring through hours of documentary footage that charted the creation of the album Let It Be.
Advances in audio technology allowed them to restore often jumbled and confused audio, and select and isolate voices and instruments. They were then able to apply the same technology to Lennon’s demo of ‘Now And Then’, helped by the fact that Sean Lennon shared the original cassette – Yoko Ono, it transpired, had shared a third-generation copy. With Lennon’s vocal and piano playing now separated out, McCartney, together with Giles Martin, son of George Martin, and Ringo Starr, could finally lay down the song as originally planned.
They were even able to utilise Harrison’s contributions from 1995. It had taken 44 years and three distinct recording sessions in three different parts of world for the final Beatles track to be made possible, thanks to the ever-evolving nature of capturing audio. Sound recording has increasingly become more accessible to all, from the humble podcast to the home recording studio. It’s hard to envisage where the next leap may take us, especially when you consider that it was once unthinkable to separate Lennon out from his piano or for us to ever hear the sound of Scott de Martinville’s soot-etched singer.
It could even be argued that we’re no longer making sound physical anyway. If the sound is now digital then it’s as untouchable as the vibrating sound wave.
