|
Audio Asylum Thread Printer Get a view of an entire thread on one page |
For Sale Ads |
58.169.46.16
In Reply to: It has nothing to do with digital vs analog. It has EVERYTHING to do... posted by NewStevo on September 14, 2006 at 13:13:24:
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.
Follow Ups:
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).
This post is made possible by the generous support of people like you and our sponsors: