在昨晚新發現的網站上，小弟又多閱讀了幾篇 paper，我發現我犯了一個很大的錯誤，需要向大家道歉並且更正。
由於有許多音樂界的工作人士，他們都有能夠感覺到不同 CD-R、不同燒錄機、不同燒錄倍數燒錄出來的音質有不一樣的經驗，例如 Digital Domain 網站上，Bob Katz 的這篇說明 jitter 的文章
http://www.digido.com/index/pmodule...der_page_id=28/
最下面 "Can Compact Discs contain jitter?" 的部分提到，他可以感覺出接 AES/EBU 的獨立燒錄器，音質比接電腦的 SCSI 燒錄器差（我想這是應該的，因為 AES/EBU 接線的關係），同時他覺得那台 SCSI 4x 燒錄，音質比 1x 燒錄差。
或者像這篇 Roger Nichols 在 EQ 雜誌上的文章
http://rogernichols.com/EQ/EQ_2000_02.html
或者像這篇
http://www.johnvestman.com/digital_myth.htm
因為有許多人都有類似的經驗，所以便有人開始研究原因，在 1996 年的 101st AES Convention，Ian Dennis 和 Julian Dunn 發表了一篇論文，名稱叫做 "An Investigation Of The Sonic Differences Between
Numerically Identical Compact Discs"
Abstract: It has been observed that CD media apparently containing identical data can have varying subjective sound qualities on replay. It is difficult to suggest a theoretical basis for this. This paper describes an analytical study of a variety of CD media and players in an attempt to identify the differences and to isolate their causes. The research is still in progress.
我在閱讀這篇 paper 的開頭看到這一段：
The most interesting question surely is: "How can the discs
sound different if the numbers on them are the same?". It is
indeed hard to offer a rational explanation, though many
explanations have been offered. It seems from a technical
standpoint that the fault must, by definition, lie in the
reproduction system.
A common theory is that physical imperfections in the 'pits' of
the CD cause timing variations in the recovery of the EFM data,
which are carried through to the player's digital-to-analogue
converter (DAC). This 'sampling jitter' could cause significant
audible degradation, as has been documented in [2], [3].
However, this theory misunderstands the basic architecture of
the player: the timing clock of the DAC does not commonly
depend on the recovered EFM data timing, but is derived from
a free-running and stable crystal oscillator. The data is buffered
in memory between the disc-reading electronics and the DAC.
This buffer is emptied at the crystal oscillator rate, and kept
half-full by varying the rotation speed of the disc; therefore
jitter in the recovered EFM data should not affect the clocking
of the DAC.
[2], [3] 那兩篇論文是
[2] Julian Dunn - `Jitter and Digital Audio Performance
of the AES UK Conference 16-17 May 1994, pp 148-166.
[3] Julian Dunn and Ian Dennis - `The Diagnosis and
Solution of Jitter-Related Problems in Digital Audio Systems'
Pre-print 3868, presented at the 96th AES Convention,
Measurements' in `Managing the Bit Budget', the proceedings
Amsterdam, February 1994.
（作者一樣是這兩位）
原來我過去認為的是錯的
這篇文章作了許多實驗，最後的結論有一段
The effects of disc-related or servo-related sampling jitter have
NOT been found in either two-box or one-box players.
Sampling jitter has been widely cited as a significant artifact in
CD players by writers in both the consumer and professional
audio fields. It seems possible that the sidebands produced by
amplitude modulation may have been mistaken for the
sidebands characteristic of sampling jitter modulation.
1997 年版的 pdf 可以在這裡下載
http://www.prismsound.com/downloads/cdinvest.pdf
slide 有圖
http://www.prismsound.com/downloads/cdinvest.pps
有興趣的人可以下載。
所以 adelies 兄的想法是對的，小弟必須要向您道歉，請您原諒小弟的自以為是 ^^;