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November 7, 2018 - 3:38am
#1
16/44.1 digital recording (on vinyl): source of ultrasonics
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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.
I'm completely agnostic on the proposition because since my 35th birthday or there-about I have absolutely 0 hearing above 17 KHz and very little at 15KHz. There is, in fact very little musical information past 7KHz anyway. Instruments just don't play that high. However there ARE harmonics in many analog recordings well into ultrasonics and I'm not convinced they don't affect the playback of LP's. Because of this, I'm inclined to believe (as in I don't KNOW these things) 2 things. At 33/45 RPM right up until the middle or so of a 33 RPM side and full through a 45 RPM side, an LP contains all the INFORMATION needed for superior playback well into ultrasonic harmonics, discounting for misaligned cartridges, excessive low frequency "bounce" (read suspended, over damped plinths), bearing chatter in the arm, etc, etc. The reason I say all this is that the implication of the OP is that digital is showing off a shortcoming of the analog format - when it's possibly showing off a shortcoming of digital recording artifacts OR as I suggest in my Subject a stylus being underdamped by too low a tracking force OR a worn rubber suspension grommet in the cartridge (gummy-muffin, if it's an Ortofon). It seems sort of a silly thing to worry about, IMO.
One common source of ultrasonic oscillation is a poor gound connection where an RCA cable does
not fit tight enough on the jack it is connected to.
Check for tight fit on the outer part of the connector and try switching cables in some places.