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In Reply to: The room we are in is the "Vinyl Asylum" and Vinyl is an analog format. posted by Teresa on September 14, 2006 at 12:54:33:
with posting information that is completely untrue. Vinyleer may know what he's talking about, but the creator of that plot does not. And neither do you. You may like perpetuating completey erroneous info regarding digital, but some of us do not. The same holds true if you were trying to pass off pseudo science with respect to vinyl. Bad info is bad info, regardless of the format.The plot posted by Vinyleer is laughably ludicrous. If you believe that a 10kHz sine wave looks anything like what that figure portrays at the ANALOG OUTPUT of a CD player, you are more than sadly mistaken. Stop spouting nonsense and go look at the output of a 10kHz sine wave using an oscilloscope if you need convincing that the plot posted by Vinyleer is WRONG.
Follow Ups:
the only way a CD player could ever possibly output anything approaching a smooth sine wave at 10 kHz, let alone 19kHz is if it had an internal algorithm that GUESSES that the signal should be sine rather than relying on the supplied data avaialble.I'd lay bets that they are set up to output smooth sine waves at the upper frequencies based upon repeating intervals of sampling that give clues to spot frequencies and that if you feed them with a triangular wave, a sawtooth wave or a pentagonal wave they'll still output a very beautiful sine that you can John Elison can display on your CRO screens to prove that there's full recovery of the high level signal.
Digital boys, try this on for size: You cannot recover data that has not been recorded. It's that simple. to argue otherwise is futile.
which is behind the whole concept. Mathematically, you CAN faithfully recover the entire signal. Implementing the 'math' with real world hardware is the challenge, but it does a darn good job of performing the 'ideal' mathematical function.
...it cannot be recovered. it can be guessed at but it can't be manufactured from nothing.Go back to wathing old episodes of Knight Rider where grainy pixel images are "enhanced" to perfect quality. It's just as easy to believe.
That's like having a theorem that identified oval shaped pale brown enclosures and outputs a signal for "eggs" to your cathode ray osillyscope.
http://www.lavryengineering.com/documents/Sampling_Theory.pdf
What you mathematically expect and reproduce MAY have been what was there but I'm afraid that's approximation and assumption, not reprodution.I accept the fact that if it look like a duck, quacks like a duck and shows up on the CRO as a duck then it's close enough for most people but frankly, showing your sample points for a given waveform, crunching the formula for that particular case and showing that you fairly much get what you put in back again is proof of clever maths giving a pretty good guess at the original (to the point where you'd agree that it's a duck).
Heck, for 95% of folks MP3 is good enough. Theresa wants a pure analogue reproduction chain, you're happy enough with CD. Whatever, I really don't care and frankly, I'd rather be listening to music than arguing net semantics or dredging through graphs and equations (yours or Theresa's).
We deserve the same respect. Pro-Digital propaganda belongs on Digital Drive. I have seen many plots of 10kHz sine wave and this looks very close. Didn't you notice the stairsteps are much smaller on the 192kHz DVD-A plot than on the 44.1kHz CD plot? It is common knowledge that CDs have a big problem reproducing 10kHz sine waves.This is correct. Take your propaganda where it belongs to Digital Drive.
"Analog is Music, Digital is mathematics"
Happy listening,
Teresa
alright.. in reading the original post-- i can surely see where you're coming from. bad science isn't necessarily science.the 10k sine wave would have to be magnified ridiculously to see the dithering at the same scale, no doubt. BUT- the theory isn't incorrect-- dithering is a digital fact. noise is an analog fact. choose your poison, i guess.
regardless of the format though-- i think you're right to stand up for accurate information, even if it ain't popular. there's a lotta kneejerkery and snake oil out there-- so even if it's unpopular, i'll stand by that.
that said.. mebbe the digital vs. analog argument aughta just.. umm.. remain like talking religion or politics at the christmas table..
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