The sound of digital music

Is the sound of music you play on Youtube good enough? Do audio streaming services provide a better quality sound? Is it still worth buying original CDs? Does it matter at all to listen to pristine, high-definition sound, or should we be satisfied with average MP3 music? What is “high-tech” when it comes to sound?اضافة اعلان

It is a long debate that started with the advent of digital sound in the late 1980s, and it has been on ever since. The title of this story is “The sound of digital music” but it could simply be “The sound of music” (no reference to the feature movie of the same name), given that digital is virtually the only format used today and the only one we have known for the past 30 years or so.

The fact is that you almost never listen to recorded music the same way. You could be driving in your car, sitting and chatting with your friends, or working at your computer while music is playing in the background. If you are listening to music with video content, like on Youtube or in a movie, your brain will be more tolerant towards average sound, because the images will partially distract you from the sound part of the content.

At the other extreme, you may be doing nothing other than listening and giving the music all your attention, sitting in your quiet living room. Or you may be listening through quality headphones, with your eyes closed. These are cases when you need the best sound digital technology can produce

Therefore, in each of the above cases your demand of quality will be different. How enjoyable the sound may be is a rather subjective matter in the end.

Still, there are solid facts, scientific physical considerations, and numbers.

Just like our eyes have capabilities and limitations, so do our ears. In terms of frequency, a human being can hear sounds between 30 and 15,000Hz, typically. This varies a little from one person to another, and of course a lot with age. Also, being able to distinguish one given instrument among the many performing simultaneously in a symphony orchestra, for example, varies from one recording to another and from one person to another.

It is generally accepted and agreed that the technical specifications of the standard audio CD are the best that a person can perceive. These are a frequency spectrum of 20 to 20,000Hz, and digitization done at a rate of 44,100kHz (called sampling rate) in 16-bit computer format. This was the norm adopted by the industry circa 1985, and it is still the main one used today. It is often referred to as uncompressed sound.

Whereas the frequency spectrum covered has hardly changed since, later technology allowed for higher sampling rates of 96,000kHz for example, and 24-bit format. It was also agreed to that very few ears — if any — could tell the difference between the original standard and these high rates. Today these ultra-high resolution recordings remain available in rare cases and are only bought by demanding purists.

Because uncompressed sound takes up space, about 10MB per minute, to save storage capacity and network bandwidth technology came up with compressed sound, the most popular being the ubiquitous MP3, the brainchild of German mathematicians. Without going through too many details, compressed music saves space and internet bandwidth, but at the expense of quality. How much space is actually saved and to what extent quality is reduced varies a lot and it alone could be the subject of a separate article.

 The fact is that today, many years after it all started, data storage and network bandwidth have increased tremendously, becoming not only widely available, (even wirelessly), but also inexpensive. One wonders if compressing music still makes sense and why they are still doing it this way.

Youtube provides reasonably compressed sound with its videos, making it acceptable if you are watching the images at the same time, but less acceptable if you are not. Dedicated audio streaming services like Spotify for example, let you set the quality to your liking — a smart approach.

Sale of audio CDs (uncompressed audio) have started to decline regularly since 2000. Today they account for less than five percent of music industry revenue. In the US, the numbers have dropped from 870 million units sold in 2000 to a mere 32 million last year.

Specialists agree that even if you are willing to put up with compressed, average quality sound, your ears (i.e. your brain) in the end get accustomed to whatever you feed it. The rest is a matter of personal choice.


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