[With grateful acknowledgments to Wikipedia.]1877: Edison invents the phonograph.
1889: Berliner invents the gramophone disc.
1906: Lee De Forest invents the vacuum-tube amplifier.
1920s: Electrical recording begins to surpass mechanical recording in terms of sound fidelity.
1930s: Magnetic tape invented.
1940s: Vinyl records offer improved performance.
1947: Shockley, Bardeen and Brattain invent the transistor, which gradually replaces the vacuum tube and allows miniaturization of audio equipment.
1966: Dolby's noise reduction system brings a key advance in audio fidelity.
1983: Digital sound recording and compact discs initiate a massive wave of change in the consumer music industry. Typical consumer equipment today (2007) provides 24-bit audio (meaning that quantization noise is negligible, at -144dB), a signal-to-noise ratio of at least 93dB, and a total harmonic distortion of only 0.01% over 1kHz. This means that digital media can capture sound perfectly over a dynamic range of 90dB, from a soft whisper (20dB) up to the sound intensity at the front rows of a rock concert (110dB).
1990s: Audiences and music consumers demand higher and higher loudness. Recording engineers and broadcasters turn up the knobs in a loudness war, resulting in sound waveforms hitting the digital ceiling and causing distortion and a reduction of dynamic range. Today (2007) it is common for CDs to have RMS levels of -10dB to -5dB; the dynamic range is probably only 10-20dB, out of the possible 90dB. I don't know how to estimate how much "total harmonic distortion" is caused by the clipping; my guess is at least 1%, much greater than the intrinsic 0.01% specification of the equipment. The days of hi-fi are gone.
Please watch this two-minute video: http://www.youtube.com/watch?v=3Gmex_4hreQ, and have a look at the section called "Dynamic Range: Then and Now" near the bottom of this page: http://mixonline.com/mag/audio_big_squeeze/.
The video gives a good explanation, but it understates the severity of the issue. It suggests that signal clipping causes just the loss of drum transients and dynamic range. It has much worse effects than that. It causes utter destruction of tone quality for non-percussion instruments. Please compare the following recordings of the opening of Beethoven's Pathétique Sonata. The second one is boosted by 14dB relative to the first. (The files are 34 seconds long. They do not play properly in some players---sorry about that.)
PathetiqueOpeningOriginal.mp3
PathetiqueOpeningClipped.mp3
3 comments:
Nigel Tufnel: The numbers all go to eleven. Look, right across the board, eleven, eleven, eleven and...
Marty DiBergi: Oh, I see. And most amps go up to ten?
Nigel Tufnel: Exactly.
Marty DiBergi: Does that mean it's louder? Is it any louder?
Nigel Tufnel: Well, it's one louder, isn't it? It's not ten. You see, most blokes, you know, will be playing at ten. You're on ten here, all the way up, all the way up, all the way up, you're on ten on your guitar. Where can you go from there? Where?
Marty DiBergi: I don't know.
Nigel Tufnel: Nowhere. Exactly. What we do is, if we need that extra push over the cliff, you know what we do?
Marty DiBergi: Put it up to eleven.
Nigel Tufnel: Eleven. Exactly. One louder.
Marty DiBergi: Why don't you just make ten louder and make ten be the top number and make that a little louder?
Nigel Tufnel: [pause] These go to eleven.
[Catherine lols] Wahey, Princess, what an apt comment! Thank you very much! You just taught me about the "These go to eleven" idiom. Seems that librarians know everything.
[rl] Actually, this post applies to pianists as well. On an acoustic piano, it is always possible to hit a note a little harder than you already did, up to the point where you break the key mechanism (or your finger bones). Digital instruments, however, max out at 127. I don't know whether I hit that limit much while playing. If so, the solution, of course, is to play everything else a little bit softer. I wonder if the range of MIDI velocities, 1-127, corresponds to a 90dB window of loudness.
You have GOT to watch This Is Spinal Tap. That is what this passage is from. It is a fictional documentary of an imaginary 1980s band on tour. And then check out IMDB.com to find out all the inside jokes!
Gosh it's been years since I saw that. Time to watch it again. Any way we can stream it into Faeria for a group experience?! THAT would be a blast.
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