March 19, 2023

Information Technology by cobuman

Analog versus Digital Music and Sound

Although the 1950’s are primarily remembered for rock and roll, what many don’t realize is this decade also brought upon many advances in digital audio recording. The dawn of this technology left scientists, audiophiles, and music fans alike asking the same questions – what’s the difference between analog and digital recording, and is one “better” than the other?

To understand this quandary, it’s important to understand the differences between analog recording and its far younger counterpart, digital recording. Thomas Edison’s phonograph was the first machine capable of capturing and reproducing analog sound. The invention, which began as an effort to play back recorded telegraph messages, was introduced in 1877.

inventor; Thomas Edison with cylinder phonograph
inventor; Thomas Edison with cylinder phonograph

For telegraph messages or songs to be recorded by a phonograph, the sound must go through a few steps. First, sound waves enter through a predecessor of the microphone, the “microphone diaphragm,” and vibrate. Next, a small needle connected to the diaphragm vibrates in sync with the vibrations from the microphone diaphragm – this causes the needle’s tip to scratch grooves into a tinfoil cylinder.

To play back a recording, the process is essentially reversed – as the tinfoil cylinder rotates, a needle follows the grooves created by previous recordings. The needle then vibrates, causing sound to flow from the microphone diaphragm. The phonograph paved the way for the gramophone and later record players – although this method of recording may sound barbaric, on a fundamental level today’s digital audio isn’t produced in a much different manner.

Max Mathews playing a violin at Bell Telephone Labs (1970)
Max Mathews playing a violin at Bell Telephone Labs (1970)source:wikipedia

In digital recording, audio signals are picked up by a microphone and converted into a nearly endless stream of numbers – these data points represent the change over time in air pressure. To retrieve these numbers and play back the song or recording, the data is converted back into analog waveforms and is broadcast through a speaker. Nearly 100 years after Edison’s phonograph, Max Matthews of Bell Laboratories developed a process to digitally record sound via a computer in 1957.

Regardless of any differences in the recording process, audiophiles continually argue over the quality of analog vs. digital. In terms of signal-to-noise ratio, or noise generated by the recoding’s signal in speakers, digital recordings can have a greater ratio. This depends on the bit depth of the recording, or the ease by which sound is retrieved.

Because digital audio comes from data as opposed to etched grooves, it’s more difficult for data to be extracted from digital recordings; analog sound is retrieved in a more “smooth” manner. Analog is not without its downfalls though – as anyone who has ever listened to a record can attest to, grooves leave the potential for dust and other contaminants to cause a popping sound on the recording.

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