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hollowman
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Joined: May 28 2009 - 12:59pm
16/44.1 digital recording (on vinyl): source of ultrasonics

Watch the following YouTube video (it's about spectral analysis of the 1985 digitally-recorded Beach Boys album, which was released on vinyl):

https://youtu.be/9MxJtMcRidw

The vlogger concluded that post-22khz content is "inaccuracies in vinyl" or "cartridge mis-tracking".
But I'm not sure I buy that. For one, he did not repeat the experiment with another turntable/cart. Or he didn't attempt to re-align the cart. Etc. ,etc.

What could be some reasons for the post-22k ultrasonic content shown in the video?

If anyone has ripped a digitally-recorded LP (e.g., 1980s vintage Telarc, etc) to at least 24/96k, and has Adobe Audition (or similar) music-analysis software on their PC, you can repeat YouTube vlogger's experiment. ( I would do the experiment myself, but my analog rig is in storage on the other side of the country!)

Notes:

JA, in his RMAF 2018 talk ( https://www.youtube.com/watch?v=NdjO9ZIx8ag ) reported ripping LPs with an Ayre QA-9 and Pure Vinyl. Hint, hint, wink, wink, JA!!

It's possible that beyond-22k energy (noted by vlogger) is generated by cart./stylus.
Perhaps as Peter Lederman (Soundsmith) discussed in his 2018 RMAF seminar:
https://www.youtube.com/watch?v=F65mODzn4Gk
(i.e., mass of stylus, moving magnet (or MC), dumps energy back to diamond tip/groove interface). And the above-22khz energy content is (are) harmonics of the music signal.

JA noted ultrasonic content of ripped LPs (e.g, Obie Clayton) in his Oct. 2000 article "What's Going on Up There?"
Similarly, Dr. Rob Robinson (Channel D) noted ultrasonics beyond 90k in LPs he ripped:
http://www.channld.com/vinylanalysis1.html

Also see Robinson's myriad RMAF "Vinyl Ripping" seminars for "live" demo of spectrogram. E.g.,:
https://www.youtube.com/watch?v=Hi6WGA59iSs&feature=youtu.be&t=1055

In Dr. Robinson's 2015 RMAF seminar ...
https://youtu.be/AlYZssmX5Bw
(at time 16:30), he does note that cutter head maxes out at ~50khz. But ... he further explains that that is only a mechanical limitation. But LP still shows content out to beyond 90k!!

hollowman
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Joined: May 28 2009 - 12:59pm
Any takers on this experiment ... JA???

Unfortunately, my analog rig is over 2k miles away, boxed up.
Otherwise, I'd repeat the experiment in the OP.

What you need:

** A lossless ripped file (wav, flac, etc.) of an LP album that was recorded digitally (e.g., Telarc, etc.). The rip should've been at least 24-bit/96k. Preferably, 24/192.

** A computer with installed software like CoolEdit or Adobe Audition.

Then:

Analyze the file in software. You can use a smartphone to capture a video of your results. It's important that results be captured on video to get a "dynamic assessment".

Since I know JA has conducted experiments like this a few times in the past (see OP), I am suggesting he do the experiment and post it on the Stereophile site (and YT channel)
;-) !!!!

If we get that far ... perhaps we can analyze the output of open-reel decks. But that's a project for the future.

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