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The MP3 Audio revolution

Revolution! The term is defined in Webster's Ninth New Collegiate Dictionary as "a sudden, radical, or complete change", and as "activity or movement designed to effect fundamental changes in the socioeconomic situation".

Armed with this definition, it can be seen that a major revolution is afoot in the audio industry. Slow to be introduced at first, this revolution is rapidly gaining momentum and will soon change everything about audio as we now know it.
Most people don't even realize that it is happening now. The revolution will be both good news and bad news for audiophiles.

This revolution is called MP3. This technology is a COMPRESSION of audio files in computers to smaller file sizes (measured in kilobytes - kb). MP3 permits audio files to occupy less disc space on hard drives, and allows music files faster transmission times over the internet. MP3 is a spinoff of MPEG video compression, but now applied to audio.

MP3 may change the entire socioeconomic system of music distribution to the extent that bricks and mortar music stores may soon be history.
The new music format will be distributed in a way which displaces the traditional way of distributing music via music stores.

I interviewed an audio engineer and recording artist recently about MP3. He was very experienced in digital technology and had twenty years experience behind him.
He explained to me that audio compression is completely different than digital sampling as found in CDs. To understand audio compression technology, let's first review digital recording and playback.

A sound wave consists of a vibrating wave at a fixed frequency. It travels at the speed of sound. The sound wave has a fixed wavelength, and vibrates at a corresponding frequency. The higher the frequency, the shorter the wavelength (inverse relationship).
Music consists of many different sound waves at various frequencies, some of which are related to each other through multiples of a single fundamental frequency (multiples are called harmonics).

The best way to understand digital technology as it pertains to audio, is to think of sounds (musical notes) and then sample it at a particular time interval.
So, a particular sound may consist of many different frequencies, each at a particular amplitude (in a typical X-Y plot, frequency is on the X axis, and amplitude is on the Y axis. In digital sampling, the waveform is sampled at a particular rate (cycles/second - Hz), and so that NOT every frequency of the sound is represented in the audio sample.
Some frequencies will be absent. In terms of calculus, think of the audio waveform as a curve in the X-Y plot with a defined area under the curve. Then apply integration to calculate the area under the waveform, but do not consider every frequency in the sound. This is how a CD is generated. Upon playback in a CD player, the missing frequencies are reintroduced upon digital to analogue conversion, so as to regenerate the entire sound in its entirety.
One can think of it as filling in the frequency gaps under the sound curve. This explanation has been simplified somewhat to make it understandable in a short space, but the principle holds true.

In digital sampling some frequencies are NOT represented in the sound curve, and have an amplitude of zero. Upon playback, the frequencies are reintroduced so as to produce a smooth sound curve.
In a typical 16 bit CD player, the sound is 8 times oversampled at a rate of 352.8 kHz. Often 18 bit digital to analogue (D/A) converters are used.

Digital music recording and reproduction contrasts sharply with analog, where the analog signal is faithfully recorded and reproduced at ALL frequencies (NO sampling).

Enter AUDIO COMPRESSION. This format uses computer power measured in bytes (example - 1 byte=8 bits, each bit being a 0 or a 1). A sound signal composed of many different frequencies is divided into the different frequencies with each frequency assigned a specific number of bits. In this fashion some frequencies will be assigned many bits of computer power, while other frequencies will be assigned less number of bits.
Unlike digital sampling where some frequencies of a sound signal have NO representation, only to be filled in later upon reproduction, in audio compression some frequencies will simply have little representation in terms of bits, but not necessarily no bits.
In this fashion, an audio signal can be compressed in terms of total bits used (and thus total bytes of computer power) resulting in a much smaller file size. This results in less space utilization on the hard drive for storage, and much faster transit time during file transfer over the internet. Again, some simplification has been introduced to make the topic easily understandable in a short space.

MP3 music files can be listened to via an MP3 player (fixed software in your computer, or a portable MP3 player). MP3 files can be downloaded for free from various internet sites, loaded onto your computer hard drive for storage, and played back through your sound card, and through any one of many portable MP3 players (the MP3 files are transfered from the hard drive to the portable player). All this without use of a CD!

What do MP3 audio files actually sound like? Proponents of MP3 claim this format to have CD like quality. The sound of MP3 is quite good for the average listener. It is NOT audiophile quality however. It is not quite as good as CD, but it is close to CD on casual listening. There are many variables involved in evaluating MP3 sound quality.
They are 1)file size, 2)sound card quality, 3)speaker quality, 4)portable MP3 player quality, and 5)sound source quality. So in evaluating MP3 sound quality, several variables have to be considered.

The recording industry feels threatened by MP3, and just very recently won a lawsuit against MP3 for violation of music copyright. Songs could be downloaded from various web sites without payment to the recording artist and the recording company - in other words no royalty payment was exchanged.
This could threaten the very heart of the music industry because if users could download songs for free, CDs would no longer have to be purchased thereby eliminating the music stores, and bypassing recording companies and artists.

Lawsuits not withstanding, MP3 is here to stay. What will most likely happen in the not too distant future is that music stores may completely vanish. Users will download music selections (some for free AND some for a royalty fee), and store the selection in their computer. The music selection will be able to be played either on a MP3 portable player (as is available now), and on a CD which will be immediately generated in the user's computer on a CD-Write unit.
This CD could then be played on a home stereo system. In effect, end users will be burning in their very own CDs on their computer. This will eliminate the manufacture and distribution of CDs to music stores.

Instead music web sites will provide huge number of selections of songs, either as complete downloadable MP3 music to fill an entire 650 MB CD. Or alternately, users may be able to mix and match music selections to create their own unique CDs.

Where does all this leave the dedicated audiophile? If the demise of the mass distributed pre-recorded CD comes true, then it is very likely that the recording industry will produce in very limited quantities true 16 bit (or to come, 20 bit) CDs just like are now present, but only marketed to the audiophile - and at inflated audiophile prices (due to the low quantity produced). Ah, the wheel is reinvented!

To summarize, brick and mortar music stores, as we know them today, may vanish. In their place, virtual web based music stores and recording companies themselves will provide MP3 downloadable music for the average listener (some songs for free, and some for a set charge).
Most people will listen to music on their computer, or on a portable MP3 player, or on a CD-Write generated in their own home computer and played in their stereo system. For the audiophile, 16 bit (as currently available) or 20 bit prerecorded CDs will still be available through the web based music stores and directly from the recording companies themselves, but at an audiophile price (read : higher price).

In effect, their will be two classes of music listeners. The average person will use MP3 generated music (player or CD-Write generated).
The audiophile will have still access to the same CDs as currently available, but in much smaller quantity. This will drive the price of current CDs up because they will have the superior sound quality.

Fact or fiction? Only time will tell, but all the signs point towards the revolution described here. CDs make way for MP3!

Copyright © 2000 Harvey A. Kader - https://www.tnt-audio.com

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