On Thu, Aug 14, 2008 at 9:58 PM, Goodsounds < [EMAIL PROTECTED]> wrote:
> > So, what is your take on the CD quality issue? I personally prefer > vinyl to plastic based on my listening experiences, but do you think > that to be unfounded? Wow. A vinyl fan who is actually open to the possibility that CDs might actually be better? I think you are the first I've ever seen. This has been a hotly debated topic ever since the CD came out in the early 80s. This is unfortunate because there's a perfectly good way to settle the issue scientifically, once and for all. My reasoning is as follows. The purpose of an audio reproduction system is to reproduce the original signal as faithfully as possible. It should not add or take away from that signal in any way. Making a recording sound "good" is the job of the recording engineer; it is not up to the reproduction system to modify the engineer's work product in any way. Ergo, if you can't tell the difference between the original and reproduced signal, then you can't complain about the quality of that reproduction system. So here's what you do. You start with your favorite test signal in analog form. It can be from any source you like, including a vinyl record; your choice. You produce a digital version of that signal by running it through a 44.1 kHz 16 bit/sample A/D and D/A, being careful to set the overall analog gain to exactly unity (0 dB). Now we have two analog signals, one direct from the input source and the other having been passed through the codec. Next you construct two audio switches. The first switch, the listener switch, has two positions labeled simply "A" and "B". The second switch, the control switch, has four positions and is physically placed so that the listener can't tell its setting. The control switch affects the behavior of the listener switch as follows: 1. Positions A and B both play the analog signal. 2. Position A gives the analog signal, position B gives the digital signal. 3. Position B gives the digital signal, position A gives the analog signal. 4. Positions A and B both give the digital signal. It's important to construct the circuits so the listener has absolutely no cues as to the setting of the control switch. For example, there must be no audible switching transients or changes in gain, latency, bandwidth or phase. This means ensuring there is no perceptible latency in the A/D - D/A chain. You can see what comes next. The experimenter randomly chooses a control switch position. The listener must then determine whether the listener switch does anything. Note: the listener is NOT asked to determine which position is analog or digital, or to evaluate which one "sounds" better. He only has to tell if the switch does anything or not. You do this a number of times, each time setting the control switch to a random position determined by a pair of coin tosses (the experimenter should NOT choose the switch position by himself). The bottom line is simple. If the listener can't tell with better than chance accuracy whether his switch actually selects between the original and digital signal sources, then it is clear that the digital path is not modifying the signal in any detectable way. And if he can't detect the difference, he can't claim that the digital system is somehow "worse". The listener may have other perfectly reasonable reasons to prefer a vinyl version of a recording over the CD. For example, the mixing and equalization on the LP might be subjectively better. But that is not something you can blame on the CD (or digital audio) per se; the fault is the recording engineer's who prepared the signal given to the CD mastering system. --Phil
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