ksoholm wrote:Analogue record playback is a very high-distortion affair, brought about mostly by the needle-record interface. The very best cartridges add about 3-5% distortion to the signal; this cannot be helped.
According to my own measurements, you can divide your figures by 5 at least to be in the right ballpark
Then pivot arms do add distortion, but its amount depends on many factors (length of the arm, shape of the stylus) and linear tracking virtually eliminates it. Still more distortion than CD, but definitely not 3%, at least not with decent, properly adjusted equipment.
ksoholm wrote:The question is, rather, why some vinyl still sounds good in spite of the high distortion. And much of it does. But, digital music formats have orders of magnitude lower playback distortion.
There is not only THD, there are also the mastering issues. Looking at how some (well, many) CD's are abused to sound louder is very informative on why they can sound worse than properly mastered vinyl. Someone said somewhere (it might even be here) that while comparing several generations of the same album he had discovered that the multiband compression had been progressively made more and more aggressive, in the obvious purpose of winning the loudness war. Strangely, now that vinyl is regarded as an "audiophile" format it seems to receive more care than when it was a mass-market industry, whereas CD is following the opposite road. It is not very difficult to eventually be better in these conditions