Digital Audio

The human body responds to five basic stimuli and one of them is sound. From time immemorial, man has been creating music, which, like man, has evolved with the passage of time. From Edison’s Phonograph to Steve Jobs’ Apple iPod, here we will talk about everything audio and also give you an insight into the world of digital audio.

Evolution

From the time we homo-sapiens learned to understand sound and create it, we have also played around with it. Be it anywhere on this planet, irrespective of religion and caste, all stories have had music associated with them. Fables usually had a bard singing for his damsel, or the Pied Piper luring the children with his captivating tunes. Music is everywhere and with music comes sound.

Although we know about Bach, Beethoven and Tansen, none of their original renditions are available to us as played by them. That’s because there were no methods of recording anything at the time, except in the form of written musical notes. Thomas Edison was someone who changed the scene with his invention of a device that could record and playback sounds.

Christened the phonograph, this invention came about as a byproduct of another experiment he was conducting to develop the Morse code. The technology that led to the phonograph came from developments that Edison made in the telegraph and telephone.

At the time, Edison was experimenting with how a moving diaphragm that was linked to a coil could produce a voice-modulated signal. Meanwhile, he was also experimenting with a telegraph repeater that was simply a device that used a needle to indent paper with the dots and dashes of the Morse code.

From these two ideas came the concept of attaching the stylus from a telegraph repeater to the diaphragm in the mouthpiece of a telephone. The first test in July 1877 involved a sheet of paper pulled under the needle, mechanically coupled to a diaphragm, as he shouted into the mouthpiece. This however, didn’t work but it did produce an unrecognisable sound, which was enough to prove that the concept was right.

Edison then went on to improvise on this and replaced the paper sheet with tin foil. The tin foil was mounted on a cylinder, and the cylinder was turned via a hand crank during recording and playback. Edison turned the crank and spoke the first recorded words. “Mary had a little lamb, its fleece was white as snow, and everywhere that Mary went, the lamb was sure to go”. This was the first recorded sound in the history of audio.

This, however, was just the start of a revolution in the realm of audio recording. Edison made loads of money on this invention as did his competitors. However, the storm had just begun! Soon, the market was flooded with devices such as the Dictaphone (Columbia) and Ediphone (Edison Company), though, there was another device that we would remember from our childhood that grabbed everybody’s attention and made music available to the masses.

The Gramophone

While the phonograph was being developed, a German immigrant by the name of Emile Berliner of Washington, D.C., filed and patented a talking machine that recorded and played back sound in 1888.

The technology that Emile used was similar to the Dictaphone/Ediphone, however, there was one radical difference: instead of using a cylinder, Berliner used a flat recording disc and a stylus that cut a spiral groove while the stylus in the cylinder moved up and down in a vertical cut recording format (known also as the "hill-anddale" vertical cut) to record the audio.

The main advantage of such a medium was that thousands of records could be inexpensively pressed from just one ‘master’ record. The Gramophone soon became a worldwide standard and is in existence even today. Although the wax discs have been replaced by vinyl LP’s, this device is a treasure. All this development was happening in the late 1800’s and early 1900’s. By 1930, with more technological advances, Wire Recorders became available. However, these were extremely expensive (like all new devices) and were affordable only to the rich and famous.

The Audio Tape

The ubiquitous audio tape made its appearance sometime after Wire Recorders. It soon became the media of choice to record on. Although the audio tape was still in its formative stages, it showed a lot of promise. Open reel to reel was the predominant format since the time of inception to the early ‘80s when digital audio started to make its appearance.

Depending on the dimensions of the reel and the tracks available for recording, users could store up to 12 hours of recording on it. The Standard Audio Cassette, or the Compact Cassette as it is called, is the final and completely refined version of the reel Audio tape. Philips developed this cassette in 1962 for their new dictation phone series and the Compact Cassette was never meant to be anything else other than recordable media for these machines.

However, its compact size, reliability, low manufacturing costs and Hi-Fi stereo capability ultimately led to wide market acceptance. The original audiotapes were made of Ferric Oxide, but later improvements such as Chromium dioxide and other metal combination tapes were used to greatly improve sound quality and reduce noise.

However, recording equipment, which could record on such media, was expensive and since Chrome tapes had different bias frequency requirements, it also needed more sophisticated recording equipment. These machines also used various Noise Reduction technologies, of which Dolby Noise Reduction technology remains the most used till date.

With the introduction of the compact cassette, it was widely used to archive old vinyl records. The audio cassette is still going strong about 43 years after birth but the compact disc or CD as we know it today, was what made the dent in its armour. With the advent of CDs, the digital wave was well and truly on its way.

The Digital Wave

Philips and Sony were jointly responsible for inventing and bringing the CD to the masses. Research and development started on the CD back in the ‘70s but the finished product debuted only in 1982. As usual, it took quite some time for it to be popular because of prohibitive costs. But the CD was extensively marketed and no one could deny it’s exceptional sound quality and portability, which far outweighed the high cost for many consumers. With the efficiencies of mass production and affordable pricing, CD became the medium of choice by the end of ‘80s.

Mass acceptance of the CD ended the long running reign of LP records. Skips, crackles, pops, wow, flutter, surface noise, all synonymous with vinyl and magnetic cassette tapes, were now a thing of the past. With plummeting prices and high media reliability software companies soon began distributing software on CDs. Companies such as America Online (AOL) did numerous mass mailings of their online software. And what happened to CDs that went bad? Well, people coined a new term-coasters-that referred to CDs that were unusable and were used for everything else other than their intended purpose.

Continued product development led to the CD-R and CD-R/W formats for both audio and data. Today’s higher sampling rates and bit depths have resulted in improved fidelity. The CD with its 44.1 kHz sampling rate at 16-bit depth still reigns as the audio champ, although newer technologies, catering specifically to users who want a more aural, more "being there" experience have evolved.

Technologies such as Super Audio CD, again a Philips-Sony invention and DVD-Audio are slowly doing to the CD, what the CD did to the vinyl. These newer technologies offer higher bit rates and frequencies, which, for an audiophile, is literally pleasure to the ears. We will talk about these formats later.

As mentioned earlier, the CD format was an exceptional format for both audio and data storage but with plummeting prices and more competition, mediocrity inevitably crept into the quality of the media. Also, with the penetration of the Internet in the ‘90s, another revolution was silently taking form in the digital era.

Nevertheless, before we talk about the digital revolution in its truest sense, there were other worthy adversaries. Prominent amongst these was the Digital Audio Tape or DAT for short. This technology was introduced in 1987 but was limited to the professional community and some consumers. The primary reason for this was the cost (again!). From the perspective of studios, DAT offered digital storage capabilities at relatively low costs, but these costs were too high for the masses. Another factor that made DAT recorders favourable for studios was the fact that it was regarded as a professional digital format used for original mastering and therefore bypasses the SCMS (Serial Copy Management System), allowing multi-generation, lossless digital recordings.

Sony introduced their proprietary MiniDisc (MD) format in 1998. This was supposed to be revolutionary since the size of the MiniDisc was much smaller than the regular CD but the quality of the recording was much superior and you could store up to twice the amount of content as compared to a standard CD (74 minutes). However, the MiniDisc never really gained mass acceptance despite its obvious advantages. But this was just the lull before the storm.