Opening a can of worms; Why do early digital recordings have musical info well above 22K on LPs? Where has this been discussed in Pro Audio?

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kap'n krunch

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ooooo, I LOOOOVE opening a can of worms!!! Maybe I was a fish in my previous life , LOL
OK, guys, so I was IZOing my Andreas Vollenweider "White Winds" LP, side B to be exact, and I found the usual; musical info (let's call them harmonics) WELL above 20-22K which was the topppermost frequency on that early digital recording.
Screen Shot 2022-08-18 at 3.18.02 PM.png

(there is also an "aliasing"[??] frequency tone at 20K and 16K but we'll ignore those because that is not "MUSIC" nor harmonics)

The info above 20K IS part of the music as you can see in this Spectrogram view, so why does the LP not STOP cleanly at 20K???

Why are there PLENTY of harmonics, especially on the highly percussive sounds?
I know that the stylus/cartridge will add those, but these are REALLY pronounced and go BEYOND 48K which is the top at 96K, and , if it's just the stylus /cart, then I'd say that it does that to ALL of the LPs, rendering it NOT very accurate, I mean, if I wanted to have all kinds of extra harmonics, I'd get a "harmonic exciter"!!!!

Where has this been discussed in Pro Audio? Please guide me...I am sure I missed that day in class...
;)
Thank you!:hi
 
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well, my "logic" is that if it were noise it would be random or general , just like the SACD ultrasonic noise which is everywhere, but this is part of the frequency spectrum of the original signal, you can see that is looks just like an analog or hi-res digital recording....
 
I would say the analogue signal path (equaliser, compressor, enhancer) in the cutting room is adding harmonics...
Interesting...but since I was not using none of the above and to my knowledge, when they cut an LP they actually use a HF cutoff filter (correct me if I am wrong!) this would lead to the probability of the main culprit being the RIAA EQ curve which cuts off bass and enhances the Hi Frequencies...hmmmm..thanks Stephen, I think we MAY have solved the enigma!
 
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