Path: Music

Music

Got no place to go
But there's a girl waiting for me down in Mexico
She got a bottle of tequila, a bottle of gin
And if I bring a little music I can fit right in

Adam Duritz / Counting Crows

I don't have many entries here as yet, but that's not because music is not important to me. Au contraire — I could not live without the stuff. Okay, okay, I exaggerate, as usual: I guess I could, but somehow it would not be a life worth living. In fact, if you would ask me nowadays whether I'd prefer to lose eyesight or my sense of hearing, I would hesitate for a second or two before answering. Twenty, thirty years ago I would have answered immediately, even without thinking. So, the trend is clear.

This page looks rather empty as it is, so I'll pep it up with a few words about compressed music in general. Compressing music (or, more generally, any stream of audio) works mostly by eliminating those things we (or rather most of us:-)) wouldn't hear anyway. Among the first to develop such a technology were the engineers and programmers at the Fraunhofer Institute in Erlangen, in Bavaria. They invented a compression method which is today used all over the world: MP3, which is short for MPEG1 Audio Layer3 (and which, in turn, is one standard among many from the MPEG, the Moving Picture Experts Group, a body that's concerned with compressing audio und video streams).

Why compress music (or video) in the first place? Because you get much more of the stuff onto a CD or a DVD or indeed any other storage medium: an MP3 player with a flash memory of one gigabyte can hold around 250 to 300 compressed MP3 songs whereas uncompressed it would only store about 25 tracks. The disadvantage of compression is that all compressed audio streams lose information: as I wrote, those things we wouldn't hear anyway. This wording opens up a debate that will continue until the end of time: many people (some with extremely good ears, others with extremely expensive audio equipment:-)) swear that MP3 files simply don't (and won't ever) sound like the original CD.

This observation is certainly true if the compression ratio is overdone, ie with a factor of let's say 1:20. But I think most people with “normal” ears and normal audio equipment would be hard-pressed to hear the difference between the original CD sound and an expertly compressed 192 kbit MP3 file (this amounts to a compression ratio of around 1:7). Many people would hear small differences with a 128 kbit MP3 (especially during an ABX test) and most would be able to differentiate between a 96 kbit MP3 file and the original. (By the way, “ABX testing” means that a person listens alternatively to two audio sources: one is the original sound, the other is the compressed file — but without knowing which is which. Under these controlled circumstances, which if done correctly amount to a double blind test, most people are not reliably and consistently able to distinguish between a MP3/192 kbit file and the corresponding CD track. Believe me: I've witnessed this more than once.)

I (being the perfectionist that I am) have done extensive ABX listening tests and frequency checks before starting to MP3ify even my first CD, not to talk about the whole collection. It quickly turned out that my ears can't for the life of them hear anything above 16 kHz. (That's to be expected: every decade costs a normal human being roundabout one kHz: and 20 kHz minus 4 kHz makes 16. Sad, but entirely normal.) In the end, after many trials and tests, I settled for a variable compression bit rate (VBR) in which some songs come out with just 110 kbit or less while others need 150 kbit or even more.

I have also configured my MP3 compression software in such a way as to cut off everything above 16 kHz. This sounds rather brutal, but I can't hear those frequencies even today… and increasing age means that this limit will continue to fall anyway. An audio purist will of course think of me as a barbarian but so far I have seen no adverse effects at all:-) More details about compression and MP3 will follow.


$updated from: Music.htxt Sat 18 Jan 2014 13:14:24 thomasl (By Thomas Lauer)$