The Necro Files: Fidelity on High: Say goodbye to dynamic range on CD

04 January 2008

Fidelity on High: Say goodbye to dynamic range on CD

"The recording industry has decided that since you like a bit of salt, they're going to screw off the cap and tip the entire fucking cruet on your meal." - The Ladyfingers Blog

Format wars
Hi fidelity sound. There are few things more glorious than relishing the full sized cover of vinyl, seeing the heart of the record player fed by the veins of the groove and being soaked in the full dynamic range of a high quality recording.

My father is a fan of classical music. He used to buy Herbert von Karajan conducted Beethoven excursions on vinyl, then transfer it to cassette deck for his car and personal use. We did not have a grand hi-fi setup, but it was sufficient to enjoy good music. My father was not alone, it was the norm to record your vinyl onto cassette deck. Even so, it would be ludicrous to suggest vinyl should be produced to cater for cassette quality sound. Most blindfold tests find that the sound of vinyl is superior to that of a CD, with cassettes wiped under the carpet as an embarrassing gadget of the 80s.

The justification of the industry to produce CD recordings of lacklustre quality is the way music is consumed. Most people are likely to never own a copy of their favourite song, since they can listen to it on-line or get it free on their iPods if they visit certain kiosks. If they do own a copy, it is likely to end up in mp3 format. I see certain parallels with the cassette tape of the 80s.

CD quality sound
CD quality sound is technically defined as digitised sound at 44,1 kHz and 16 bits. This is the ISO definition, the so-called Red Book ideal of what CD quality sound should be. These numbers are not arbitrary (see the Nyquist-Shannon sampling theorem), as a sampling rate of double the maximum frequency to be recorded is needed. This dictates that you need at least 44 kHz to represent an audio spectrum between 20 Hz and 22 kHz, which is approximately the range of human hearing.

The 44,1 kHz number refers to the frequency of samples taken. 16 bit refers to the size of the samples taken. For a stereo recording, 16 bits are used for each channel.

MP3 quality sound
MP3 is a compressed audio format. It works by stripping unnecessary (supposedly inaudible) aspects from sound. Since the sound is stripped, it does have lower sound quality than CD. Apple's AAC and Microsoft's WMA are currently competing with MP3 as downloaded formats, although most companies offer high quality MP3 as consumers tend to demand MP3.

Since most consumers tend to rip their CDs to MP3, or merely consume music on radio or in MP3 format to begin with, the industry insists to level the dynamic range of CD recordings. In other words, all the brights are as bright as the dull parts. Dynamic range needs the disparity between quiet and loud - something Black Sabbath calls 'heaven and hell.' CD recordings now have MP3 quality. Instead of ripping CD quality MP3s, you can only rip MP3 quality MP3. Instead of listening to CD quality CDs, you can only listen to MP3 quality CD.

Your dynamic range or mine?
I am a convert to the CD format. While I do appreciate the rich tones of vinyl, it is a matter of convenience for me to own a CD. Optical formats tend to last longer, and I can choose my own sampling rates when I rip my CDs onto my hard drive. Since I treat my CDs as master copies, I do not feel the need to buy MP3 quality CD.

Why do people still buy CDs when the odds are stacked against them? The RIAA is suing women and children - in some cases even people who rip their own CDs onto their computers. The major players are slowly realising that DRM enabled formats are deterring the already dwindling consumer market, but not fast enough. All these factors merely make it more convenient, more logical and more reliable to download unsolicited content. It removes the risk for the consumer of sitting with MP3s that can't be transferred between devices and now, thanks to the industry catering for the demands of MP3 listeners, doesn't even capitalise on the benefits of CD quality sound.

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